Experiences and perceptions of people with a severe mental illness and health care professionals of a one-year group-based lifestyle programme (SMILE).

OBJECTIVE: This was to elucidate the experiences and perceptions of people with severe mental illness (SMI) and their health care professionals with the SMILE (Severe Mental Illness Lifestyle Evaluation) group-based lifestyle intervention. SMILE focuses primarily on promoting healthy diet, physical activity and weight loss.
METHOD: A qualitative study with semi-structured interviews was conducted using purposive sampling. Interviews were conducted with 15 clients and 13 health care professionals (HCPs). Data were analysed according to a thematic analysis.
RESULTS: Four overall themes were identified: interest in a lifestyle programme; group-based setting; changes in lifestyle behaviour; and preconditions for changing health behaviour. The results showed that clients valued the programme and were interested in the subject of lifestyle. The group-based setting was seen as a positive and important aspect of the intervention. Making lifestyle changes was acknowledged as difficult, especially in combination with the presence of psychiatric symptoms. Clients acquired an improved awareness of different aspects related to lifestyle behaviour. Irrespective of weight loss achieved, clients found their efforts successful with relatively 'small' changes. Some needed more support during the intervention than others. The practical activities in group sessions were regarded as most useful. HCPs were enthusiastic about the programme and their interactions with lifestyle improvements.
CONCLUSIONS: The results of this study shed light on different aspects that were considered important when delivering a lifestyle intervention to people with SMI. We recommend considering these aspects when implementing a lifestyle intervention in a mental health care setting for clients with SMI.

Introduction

People with a severe mental illness (SMI) have an increased risk of premature mortality, with cardiovascular disease being one of its primary causes [1, 2]. Factors associated with this increased risk include, amongst others, unhealthy lifestyle behaviours and adverse effects of treatment, in particular use of antipsychotic medications which cause weight gain and metabolic abnormalities [3-5]. People with SMI tend to be less physically active than the general population, be more sedentary, have a lower consumption of fruit and fibre and a higher consumption of sugars and saturated fat [3, 5–7].

Improvements in nutrition and physical activity may have significant benefits for the physical and mental health of people with SMI [8]. Furthermore, a healthy lifestyle can contribute to feelings of empowerment, health-related self-efficacy, feelings of greater autonomy, and improved social integration and quality of life [3, 8–10].

Sustainable changes in lifestyle behaviour are difficult to achieve for most people. People with SMI face additional challenges in achieving these due to the symptoms of the psychiatric disorder, and their consequences for personal and social functioning [8, 11]. Sufficient time and support, with a focus on incremental changes in lifestyle behaviour, are needed for achieving long-term effects [11-13].

Many lifestyle interventions for people with SMI focus on weight loss and cardiovascular risk reduction. These interventions are mostly delivered in highly controlled study settings [14]. Consequently, aspects related to real-world settings in which clients function, as well as the experiences of clients of their participation in such lifestyle improvement programmes, have been little researched. For an effective lifestyle programme, the principle of tailoring the delivery of the intervention to the specific needs and preferences of individuals is essential, including consideration of influential factors from the real-world settings of clients.

Further research is needed to better understand what is important for people with SMI when engaging in lifestyle intervention programmes, in order to identify important factors to consider when tailoring lifestyle interventions to their specific needs.

We studied an extensive lifestyle programme, with a focus on a healthy diet, physical activity and weight loss, called the Severe Mental Illness Lifestyle Evaluation (SMILE) intervention. The intervention was performed during ambulatory care for people with SMI, the (cost-)effectiveness of the programme also being studied [15]. In parallel, a process evaluation was performed [16], describing the implementation process of the intervention, with an elaboration of barriers and facilitators for its effective implementation. The current study is a sub-study of the process evaluation performed with the aim of elucidating the experiences and perceptions of people with SMI and of their health care professionals (HCPs) with the SMILE intervention. Though clients’ perspectives are central in this study, we also interviewed the HCPs delivering the SMILE intervention in order to explore their experiences in parallel with those of their clients. The findings may shed more light on how to improve tailoring of lifestyle interventions to people with SMI.

Method

Study design

A qualitative research design with semi-structured interviews was used to study the experiences and perceptions of patients with SMI and of their health care providers with the SMILE intervention. This study was performed alongside a pragmatic cluster randomized controlled trial (RCT) evaluating the cost-effectiveness of the SMILE intervention in Dutch ambulatory mental health care, in combination with a process evaluation studying the implementation process of the intervention [16]. Eleven ambulatory FACT (Flexible Assertive Community Treatment) teams participated in the intervention arm of the SMILE trial which was based on the STRIDE study [17, 18]. For a detailed description of the SMILE study design, see Walburg et al., 2019 [15].

SMILE intervention

The SMILE intervention is a one-year intervention, with weekly two-hour group sessions during the first six months (initial phase) and subsequent monthly group sessions, combined with individual telephone support during the last six months (maintenance phase). It mainly focused on establishing a healthy diet, promoting moderate physical activity, and losing weight, but additionally targeted other aspects of lifestyle, such as sleep, stress, negative thinking and social support. An overview of the content of the SMILE intervention group sessions is presented in the S1 File. Group sessions, varying in size from 7 to 16 clients, were delivered by two trained mental HCPs. Their format was as follows: sessions started with a check-in, where successes and challenges experienced during the period between the sessions were discussed; this was followed by discussing one or two topics scheduled for that week; finally, participants formulated and discussed their personal goals for the upcoming week or month; there was also a 20–30 minute workout, including walking with the group or performing indoor exercises. All FACT team clients were eligible to participate in the intervention if they had a BMI of 27 or higher and were 18 years or older.

Procedures

We interviewed clients with SMI who participated in the SMILE intervention and HCPs who delivered the intervention. We included the HCPs’ perspective to improve the credibility of the findings, though the clients’ perspectives were our primary focus. We included at least one client and one HCP from each of the 11 FACT teams.

To achieve sufficient variation in the sample of clients, with a wide range of different perspectives, we used a purposive sampling strategy with the following criteria: variation in (1) attendance at group sessions, (2) challenges experienced by the client during the SMILE intervention, (3) weight change after six months, (4) gender and (5) diagnosis. All but one of the clients interviewed completed the full SMILE intervention. We included both women and men with high or low attendance, high and low weight change, and different mental health diagnoses. We also included a client who had dropped out of the study. We included HCPs based on their active involvement in the implementation of the SMILE intervention, creating a sample of all disciplines involved in the trial: mental health nurse, expert-by-experience, social worker, activity worker, and psychologist.

We used different interview guides to conduct semi-structured interviews with clients and HCPs (see S1 File). These guides were based on topic lists, the topics being based on the RE-AIM framework as this study was performed alongside the process evaluation which focuses on the process of implementation of the intervention. The RE-AIM framework assesses five dimensions to enhance the quality, speed, and public health impact of efforts to translate research into practice [19]. These are Reach, Efficacy, Adoption, Implementation, and Maintenance (hence RE-AIM). We sought to elucidate the perceptions and experiences of interviewees with the SMILE intervention along these dimensions to gain insight into the different elements of the delivery of an intervention. These RE-AIM dimensions were incorporated throughout the interviews but were not explicitly used for the analysis of the data in the present study, given our focus on the experiences of clients and professionals. Data were collected and analysed using an iterative process, in which topics were adapted throughout the interview period, and new topics added in subsequent interviews, based on information collected in previous interviews. All interviews took place near the end of the SMILE intervention period. Data collection stopped when no new information was derived from interviews (data saturation) [20]. Interviews were audiotaped, transcribed verbatim and anonymized. A member check was performed to check the credibility of the data: participants were sent a summary of their interview and asked if they recognized the main themes described.

Data analysis

Data were analysed using thematic analysis [21, 22]. All transcripts of the interviews were coded separately by two researchers (FW and JWdJ). MAXQDA 2018 software was used to facilitate data analysis. The analysis comprised six phases: (1) familiarization with the data by reading and summarizing all transcripts; (2) the generation of initial codes; (3) searching for themes; (4) reviewing whether themes credibly represented the data; (5) defining and naming the themes; and (6) producing the report. Themes derived from the analysis were compared and discussed by both researchers until consensus about the central themes was reached. Overall, there was a strong consistency between both researchers. A third researcher (HB) with extensive experience in the field of qualitative research contributed to the analyses in case of lack of consensus between the two initial researchers.

Ethics

All participants gave written informed consent in accordance with the Declaration of Helsinki. The study received ethical approval from the Medical Ethical Committee of the VU University Medical Centre in Amsterdam, the Netherlands (NL60315.029.17, registration number 2017.418).

Results

Participants

A total of 28 interviews were conducted, 15 with clients and 13 with HCPs. Clients interviewed were between 30 and 61 years old; nine were female and six male. Ages of the HCPs interviewed ranged from 30 to 62 years; ten were female and three male. Details of the characteristics of the HCPs and clients are presented in Tables 1 and 2, respectively. Interviewees could choose whether the interview took place in the mental health care institute or at home. Interview durations ranged from 22 to 53 minutes with clients and 38 to 75 minutes with HCPs. Seven (48%) of the client interviewees and all but one (92%) HCP interviewees responded to the member check, and agreed with the summaries. From the interviews, we identified four main themes and eight subthemes.

Table 1

Characteristics of interviewed health care workers.

No.	Gender	Age	Discipline	Total sessions given
HCP1	Male	60–69	Nurse	15
HCP2	Female	40–49	Activity coordinator	20
HCP3	Female	50–59	Nurse	23
HCP4	Female	30–39	Nurse	24
HCP5	Female	50–59	Nurse	30
HCP6	Female	50–59	Nurse	28
HCP7	Female	30–39	Social worker	27
HCP8	Female	30–39	Psychologist	25
HCP9	Female	30–39	Expert-by-experience	29
HCP10	Female	30–39	Nurse	28
HCP11	Male	50–59	Nurse	27
HCP12	Female	50–59	Nurse	27
HCP13	Male	40–49	Nurse	24

Table 2

Characteristics of interviewed clients.

No.	Gender	Age	Diagnosis	Weight change after 6 months	Total attendance
C1	Male	50–59	Schizophrenia or other psychotic disorder	Gain	18
C2	Female	40–49	Borderline or other personality disorder	Loss	23
C3	Female	30–39	Borderline or other personality disorder	Loss	23
C4	Male	50–59	Schizophrenia or other psychotic disorder	Loss	14
C5	Male	40–49	Schizophrenia or other psychotic disorder	Gain	18
C6	Female	40–49	Depressive or bipolar disorder	Gain	3
C7	Female	50–59	Depressive or bipolar disorder	Loss	28
C8	Female	30–39	Schizophrenia or other psychotic disorder	Gain	11
C9	Male	40–49	Schizophrenia or other psychotic disorder	Loss	29
C10	Female	40–49	Depressive or bipolar disorder	Equal	23
C11	Female	50–59	Schizophrenia or other psychotic disorder	Loss	20
C12	Female	50–59	Post-traumatic stress disorder	Loss	21
C13	Female	30–39	Post-traumatic stress disorder	Loss	21
C14	Male	50–59	Schizophrenia or other psychotic disorder	Loss	30
C15	Male	60–69	Obsessive compulsive disorder	Loss	29

Theme 1: Interest in a lifestyle programme

Clients valued the programme

Changing lifestyle behaviour and losing weight were subjects of interest for clients. Many had (repeatedly) attempted to improve their lifestyle behaviour and lose weight before joining the SMILE intervention. Generally, clients linked their overweight and their struggles with lifestyle behaviour to aspects of their mental illness, such as symptoms of their disorder and their medication use. For example: one client stated that a healthy lifestyle was important for him because his obsessive-compulsive disorder had a negative impact on his lifestyle behaviour.

"I think it’s good anyway to live a healthy life, to exercise a lot and work on my diet, because my lifestyle is dictated quite a lot by my compulsions" (C15).

The consensus was that clients enjoyed participating in the sessions and actively worked on their lifestyle during the SMILE intervention. The sessions were experienced as stimulating and regarded as a positive way to encourage behavioural lifestyle changes. The main motivation for clients to join the intervention was to lose weight and improve their physical health in general. In addition, some clients specifically mentioned the need to gain more knowledge about lifestyle-related issues, such as healthy foods and physical activity. They wanted to feel better and to increase their awareness of how to achieve this. Motivational factors mentioned by a minority of clients were more practical in nature, such as having the time available and the opportunity to join in.

Theme 2: Group-based setting

The group-based setting had many benefits

The group-based setting of the intervention was attractive for clients. Some mentioned it as one of the main motivators for joining the intervention. The group sessions were perceived as pleasant and safe to exchange their experiences and challenges in their efforts for lifestyle changes and to discuss related aspects of their mental health. Clients indicated the importance of peer support from their fellow group members which contributed to the experience of a collective effort to change lifestyle behaviour. This motivated them to attend the sessions.

"And you really do it together, you know. It is a long process that you go through. You share experiences with each other. And I think that’s what is so nice" (C13).

Clients recognized themselves in the shared struggles of the other group members with lifestyle changes. The sense of community was enhanced by the fact that they shared common characteristics, such as being overweight and experiencing mental health problems, both central topics of discussion during the sessions. The exemplary behaviour of one client could contribute to the behaviour change of another.

"I felt like I belonged in the group, because we have all common experiences, and I thought it was nice to have people around me with the same experiences" (C8).

"Recognition. And you could also see that someone who, for example, experienced binge eating, then went for a walk instead. And then I said to myself: I’ll do that as well next time" (C13).

In addition, clients said that the group setting brought them into contact with other people, which was seen as a positive experience. Some clients stated they started seeing other group members outside the group sessions, which led to new friendships.

The positive aspects of the group setting were also recognized by HCPs. They underlined the ‘power of the group’ with its supportive and helping effects on the clients.

"And I think that is really the strength of a group, that they feel very, very supported by everyone there. Because everyone understands exactly what they are talking about, because they’re all willing to show their vulnerable side. Everyone has the same problem. So it feels quite powerful, leading to change, being with people who are in the same boat" (HCP12).

Clients felt safe with the HCPs and felt they were part of the group

Clients felt positive about the HCPs who delivered the intervention. They noted that HCPs were emotionally and practically involved with their challenging efforts for lifestyle changes and the struggles they went through as clients.

"The climate during the sessions was very supportive, they really paid attention to you. Yes, a lot of attention for every person, you never felt excluded from the group" (C8).

Clients appreciated the coaching and the concrete advice HCPs gave them. They also valued the personal stories HCPs shared about their own struggles with lifestyle changes. This stimulated group cohesion: common experiences of both clients and HCPs could be shared, which led to normalization of these experiences and open discussions about possible solutions to manage lifestyle challenges. It was felt that it was important that the gap between the lifestyle behaviour of clients and HCPs not be too great, i.e., HCPs as prototypes of healthy persons versus the clients with overweight and poor lifestyle habits:

"If there had been two group leaders who were very fanatical about sports and already very health-conscious in terms of nutrition, it would have been very counterproductive" (C12).

For HCPs, group cohesion was also a recurring subject during the interviews. They were enthusiastic about their interaction with the clients and felt as if they were a part of the group, rather than being ‘group leaders’.

"I thought it was important that we, the group leaders, also shared our experiences, that we also were confronted with poor lifestyle behaviours that were difficult for us to change. People appreciate it when you say: I can’t stay away from that candy jar or something. So, I thought that was also a strength. That you are part of the group" (HCP12).

Theme 3: Changes in lifestyle behaviour

Making changes was difficult

Changing lifestyle behaviour and losing weight was acknowledged as difficult by clients, especially in combination with the presence of psychiatric symptoms.

"For me, it is a little more difficult to lose weight, in particular in periods of depression. Then, exercising is a major challenge. And that was also the big stick, that you are with the group and that you can drag each other through. So yes, I found that very pleasant" (C3).

During the intervention, clients learned to formulate their personal goals. They observed that it was difficult to formulate attainable goals and stick to them. One said:

"I found it very difficult at first, but that’s because I wanted a faster pace to make greater headway" (C12).

HCPs affirmed the complexity for clients of making changes, mentioning as one reason the diversity in levels of cognitive functioning within groups, with some clients having trouble concentrating during sessions. In their view, there needed to be sufficient time for all clients to understand the central topics discussed in each session, and to stimulate them to formulate small concrete attainable goals, leading to experience of success.

“But, in that case, it is important to realize that you have to set the goals quite low. Small goals and not too elaborate. And it is useful, especially with the SMI target group, to specify those very clearly, because they often have a lot of difficulty formulating clear and achievable goals" (HCP7).

Furthermore, HCPs noted that when clients’ goals were achieved, even though modest, it was seen as a great success by the clients.

"And I have to say that it was quite nice, because people are also very happy when they have reached that small goal" (HCP13).

Improved awareness of own lifestyle behaviour and how to change it

The most common change clients experienced was a greater awareness of several aspects related to lifestyle behaviour, such as enhanced understanding and awareness of current food intake, unhealthy foods, the function of emotional eating and other barriers for lifestyle behaviour change. This change that was regarded as an important and helpful development. One client said:

"And all those things regarding increasing awareness about lifestyle issues, that was most beneficial for me" (C12).

This increased awareness applied, among other things, to emotional eating, a frequently recurring issue for clients throughout the sessions. Clients commented that they had learned about the triggers and functions of emotional eating, and how to prevent this form of unstructured and excessive food intake. This was seen as a struggle for both clients and HCPs.

"She explained how it works if you are an occasional ‘emotional eater’. You are angry about something and you snack a little bit and then you feel guilty. And they have explained so well how it works. You can get a setback" (C11).

For clients, weight loss was not the most important outcome

Clients were happy when losing weight but the interviews revealed that clients did not experience this as the most important outcome of the lifestyle intervention. Irrespective of weight loss achieved, clients felt their efforts to be successful even with ‘small’ lifestyle changes in different areas of functioning. One said:

"I have lost some weight, of course, which is great but that is not the most important thing for me, but rather the balanced meals and the small steps with exercise, and that you just become more aware of that" (C3).

Clients experienced a wide range of changes throughout the intervention, which they appreciated. Changes related to physical activity and nutrition were: more exercise, less snacking, higher fruit consumption, smaller portion sizes, and consciously choosing healthier food alternatives. Interestingly, clients also mentioned changes that had a positive effect on their daily lives in general. For example, one mentioned a positive effect on her daily routine:

"I still used to sleep in every day but since the SMILE intervention I am often up in the morning at seven, half past seven. And then I’ll have my breakfast earlier. Because before, it was as late as 11 o’clock. And I do that earlier in the morning now. So I did change that. My daily routine has improved, let me put it that way" (C7).

Another common topic amongst clients was the improvement in general wellbeing. For example:

"Through the SMILE-intervention, I just feel better about myself. Now I actually cleaned up and organized my entire house last year" (C7).

Another client stated:

"And yes, I just dare to show myself more in society" (C9).

HCPs confirmed the positive effects on the clients’ mental wellbeing:

"And then you also see the effects of that, that they feel much better about themselves. And as a result, they’re stimulated to continue working on a healthy lifestyle" (HCP7).

Theme 4: Preconditions for clients in changing health behaviour

Clients needed time and intensive guidance for behaviour change

Most clients were capable of following the extensive one-year intervention and participating in the SMILE group sessions but some needed more support than others. For example, the change from weekly to monthly meetings after six months was mentioned as a noticeable reduction of support and structure, which was experienced as undesirable by some clients. After the one-year intervention period ended, some clients asked about the possibility of continuing the intervention with booster sessions because they needed additional support.

"Yes, well, I think just getting together once in a while for the finishing touches. That you just go through the important things again. You have the binder for guidance, but in daily life you are distracted by a lot of things, so you can lose focus a bit. Just to discuss things again and sit down together again and get that focus back" (C3).

HCPs stressed the importance of continued support over time for people with SMI to preserve and possibly further increase lifestyle changes. They recommended more guidance and additional individual face-to-face support for some clients during the SMILE intervention and the possibility of continuing group sessions after one year.

"It really is a long process. And especially for this group of patients. Most important is to stick with it for a long time, to continue to support them" (HCP12).

Learning in practice was most beneficial

The practical activities in the SMILE intervention were regarded as most useful by clients. Sessions with a very practical approach were mentioned as the most appealing. These sessions contributed most towards improved awareness and actual lifestyle changes, as opposed to more information-driven sessions. These practical approaches were supported with visual aids, also appreciated by clients. One said:

"We also received cards with foods, we had to put them in order from containing the most fats or sugar to the least fats or sugar. And that shocked people, how much sugar ice cream or an almond round contains" (C11).

In addition, another client mentioned that practical activities were preferred because otherwise it was difficult to concentrate for a longer period of time:

"Yes, they were very good at that. And yes, we could not always concentrate for a long time, you cannot listen for an hour, you know, because then the concentration is gone and so this practical approach is just very nice" (C13).

HCPs confirmed the preference of clients for practical approaches:

"People are very often visually oriented such as with those cards, then people become more enthusiastic" (HCP11).

Discussion

The results of this study shed light on different aspects considered important when delivering a lifestyle intervention to people with SMI. These clients’ experiences and perceptions were complemented with the perspectives of their HCPs. The findings have led to suggestions for tailoring lifestyle interventions in the best possible way for individuals with SMI. Four overarching themes emerged from our analysis. We found that clients valued the SMILE intervention and experienced benefits from this intervention in a group-based setting. These benefits were not limited to weight loss or behaviour changes, but extended to the appreciation of peer support, improved awareness of health issues, improvements in psychosocial functioning and mental wellbeing. It was striking that for most clients, weight loss, which was the primary outcome in the RCT we conducted, was not the most important outcome; they felt positive about all improvements in the above-mentioned areas. For many clients, changing behaviour was complex and difficult to sustain, to a large extent due to the consequences of the mental illness, for example (residual) psychotic symptoms, depressive symptoms or impairments in cognitive functioning (in particular impaired concentration). It should be noted that achieving sustainable lifestyle changes and effects is difficult for almost all people who try to realize this. However, clients with SMI are confronted with a number of additional challenges, not only the previously mentioned consequences of the mental illness, but also the confrontation with stigma and self-stigma, reduced self-esteem, less social support, fewer financial resources, and reduced access to regular sports facilities [13, 23–25]. Additional support and a practical approach are needed to help clients find solutions for the challenges they encounter.

An interesting result was the great appreciation of both clients and HCPs for the group setting of the intervention. Before starting the study, many HCPs and management staff were sceptical about its group-based design. They predicted that people with SMI would not be interested in following a group-based lifestyle intervention for one year, due to lack of motivation and inability to function in a group. According to them, low adherence to the group sessions could jeopardize the success and effectiveness of the intervention programme. While we recognize that a group setting will not be ideal for all people with SMI, this turned out to be one of the most successful aspects of the SMILE intervention. Published research also suggests that people with SMI who follow a group-based lifestyle intervention experience the peer support essential for lifestyle behaviour change, in which being together with people who are ‘in the same boat’ is considered a key feature [26]. Therefore, we would advise always to consider group-based settings when delivering lifestyle interventions for people with SMI, though with constant vigilance for possible signs of drop-out of clients who are not capable of effectively participating in these. Such clients may benefit better from an individual approach. However, when tailoring the activities in group-based lifestyle interventions to the specific competencies, needs and preferences of clients, this individual approach may also be suitable, on condition that the group size is limited. In our opinion, people who could benefit most from a group-based intervention are those who are looking for (new) social contacts, enjoy social activities or are interested in learning from peers. Group sizes from seven to ten clients turned out to be workable in the delivery of the SMILE intervention.

Many clients in this study had cognitive impairments which may be important barriers to successful behaviour change for people with SMI. Cognitive impairments were also common in the STRIDE study [11], where participants often mentioned these as a barrier to effective participation in the intervention programme and, in the end, to behaviour change. In our study, HCPs mentioned the need for using practical approaches, setting small goals and delivering additional individual support to better meet the needs, strengths and limitations of the clients. In the STRIDE study [11], participants also cited depressive symptoms as having a significant negative influence throughout the intervention. Depressed mood influenced their eating behaviour, in many cases leading to overeating. In our study, clients also mentioned this and emphasized the importance of learning how to cope with emotional eating episodes. There is a known association between depression, emotional eating and obesity [27] and we therefore recommend more focus on emotional eating, preferably with the help of psychological interventions.

Notably, clients mentioned a variety of successful lifestyle changes throughout the intervention. For clients, even ‘small’ changes were highly important and perceived as great successes. As noted earlier, for many patients, weight loss was not the most important outcome. HCPs should be aware of the possible differences between their expectations and clients’ goals when it comes to weight loss versus other forms of lifestyle change. If weight loss is not the primary goal for all clients, it cannot be the primary criterion of success.

Other beneficial effects of the intervention mentioned by clients included improved daily rhythm and mental wellbeing. Focusing on a variety of healthy behaviours such as those concerning eating, physical activity, stress, sleep, and social participation, and how to integrate these in daily life can therefore be of great interest for many people with SMI.

Overall, the interest of clients in the lifestyle intervention was greater than expected. During the recruitment process, HCPs noted that clients were interested in joining the SMILE intervention, including some who did not meet our inclusion criterion of overweight. The assumption of some HCPs that clients have limited or no interest in lifestyle improvement does not seem to be justified. Therefore, possible participation in lifestyle interventions should always be discussed with clients.

Strengths

We performed a process evaluation as part of a pragmatic RCT [16]. Our current study and the process evaluation were performed alongside each other, drawing on the same data [16]. Together they provide a comprehensive insight into process of implementation, related barriers to and facilitators of effective implementation, and the experiences of clients and HCPs with the lifestyle intervention. We added valuable scientific information to the quantitative analyses of the cost-effectiveness trial. In this way, we surpassed the ‘black box limitation’ of the RCT and provided explanatory data for the results of the trial.

Limitations

Our results shed light on the experiences and perceptions of people with SMI who decided to enter the intervention but it does not say anything on how to encourage the engagement of those not interested in adopting healthy behaviours or not willing to participate in a structured, group-based lifestyle programme. Therefore, it is plausible that selection bias has occurred as people not interested in following a lifestyle intervention were not included in the study. It is important to view our findings with this in mind. A potential limitation might be the fact that only 48% of the client interviewees responded to the member check and agreed with the summary. However, we were satisfied with this response rate of 48%, because we didn’t expect a high response rate in this population of clients with SMI.

Conclusions and implications for practice

The results of this qualitative study shed light on aspects that need to be considered when delivering a lifestyle intervention to people with SMI. To better accommodate people with SMI, we recommend incorporating the following aspects when delivering a lifestyle intervention:

Integrate group-based elements in lifestyle interventions, but recognize that additional individual attention may be needed for some clients;

Be aware of the time investment that will be needed for people with SMI to achieve stable lifestyle changes;

Recognize the complexity of changing lifestyle behaviour for people with SMI and use practical and easy-to-understand activities during the intervention, e.g. supporting the intervention with visual aids and practical activities;

Broaden the set of outcomes of lifestyle interventions beyond solely weight loss and metabolic parameters to include, for example, improved mental wellbeing, quality of life and social participation.

(DOCX)

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: N/A

Reviewer #2: I Don't Know

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3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: No

Reviewer #2: No

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: 1. Is the manuscript technically sound, and do the data support the conclusions?

This manuscript describes a qualitative research study designed to evaluate the experiences and perceptions of individuals who participated in a long-term (one year) ambulatory care (outpatient), group-based lifestyle program. All participants had a severe mental illness (SMI) (and, according to line 108, were overweight). The perceptions of health care providers (HCP) who led the group sessions were also evaluated. As acknowledged by the authors, the inclusion of the HCPs is a strength of the research as their experiences serve to complement the findings from the clients.

This research used semi-structured interviews to evaluate the perceptions of participants. Separate interview guides (described in the supplementary materials) were used for the two groups of participants. Four themes (and eight sub-themes) were identified and described. Together, these themes captured the perceived value and benefits of the program, the impact of the program on participants’ wellbeing, and factors that contributed to the effectiveness of the program. The perceptions of the HCPs complemented and extended the findings obtained from the clients. As described in the Discussion, the findings set the stage for evidence-based recommendations regarding the development and implementation of lifestyle-focused programs.

The focus of the research is important. It is well-established that wellbeing is adversely impacted by SMI. As the authors acknowledged, people with a SMI have poorer physical health and are at greater risk for premature mortality. They are generally less physically active and have a poorer diet. Other research has demonstrated that individuals with a SMI are often more isolated, experience greater loneliness, and have a lower quality of life and perceived wellbeing. While treatment of the SMI specifically is important, interventions that target lifestyle issues more generally can make a substantive difference to the wellbeing of these individuals. The described intervention is distinct from other programs that have been described in the research literature. First, it is a year-long program (weekly sessions for the first six months, followed by monthly sessions). It is offered as an outpatient group program. However, attention is paid to the needs and styles of individual clients. As described by the authors, the group nature of the intervention seemed to be a strong contributor to the effectiveness of the program.

The research is also timely. We continue to be in the midst of the COVID-19 pandemic, which has stretched health care systems to their limits. In addition, the mental health of people (with and without premorbid mental health concerns) has been adversely and substantively effected. Thus, intervention programs that focus upon lifestyle issues and that promote social connections may be especially important in the current context. In this regard, it was interesting that the researchers noted that response to recruitment attempts was more positive than expected. In particular, even individuals who did not meet the inclusion criteria wanted to participate. This was in contrast to the expectations of various stakeholders who anticipated that the group-nature of the program would limit participant’ interest. Furthermore, as indicated above, the group-nature of the intervention was found to be one of the critical strengths of the intervention.

Overall, I thought the research was well done and meaningful. I found the Introduction and Methods to be the weaker sections in that key aspects of the research were not always described clearly. The recommended revisions are relatively minor (that is, they should be easily achieved); however, they will substantively improve the quality of the manuscript.

Concerns:

1. Focus of the intervention: It would be helpful to acknowledge the primary focus of the lifestyle intervention (i.e., weight loss, physical activity) in the Abstract (Objective; lines 23-25) and Introduction. This was not clear until S1 Appendix was examined. Although there were hints of the focus (e.g., line 37, “Irrespective of weight loss …; description of the inclusion criteria (i.e., line 108), for the most part, the description of the program within the body of the manuscript was quite vague. This is problematic in that the descriptor “lifestyle intervention” is vague. Such programs can be narrow or broad. In the case of more narrow foci, programs can vary tremendously. It is recommended that the final paragraph of the introduction (lines 78-86) be revised to include a brief description of the program’s main focus.

2. The described research is part of a process evaluation of the intervention that was conducted in parallel with a pragmatic cluster-randomized control trial of the SMILE lifestyle intervention. While the main study was cited, it is not clear if the process evaluation of the intervention has been published. Moreover, it was not clear why the authors decided to present the qualitative data in a separate manuscript. While this decision may well be appropriate, it would be helpful if additional information was included about the primary process evaluation in the Study Design section of the Methods (lines 88 – 95). For example, was this evaluation quantitative in nature? If it has been published, a reference for that article should be provided (see lines 81 and 91-92). In revising this section, please ensure that the various components of the study as a whole are clearly described. Also, it may be pertinent, in the Discussion, for the authors to address the inter-relationships between the results of the two parts of the process evaluation. Are the two sets of results complementary? Are there any discrepancies?

3. SMILE Intervention (lines 96-108): Please provide more information about the structure of the program. How long was each session? What was the size of the groups (i.e., clients and HCPs; this information was finally provided in the Discussion section (lines 380-381))? Describe the SMI inclusion criterion. Were individuals with co-morbid mental health disorders eligible to participate? While a list of topics covered in the program is available in S1 Appendix, it would be helpful to describe briefly the kinds of topics addressed in the body of the manuscript.

4. Use of RE-AIM framework: It was stated that the interview guides were based on the RE-AIM framework (Glasgow et al., 2019). While this framework is very pertinent, it was not clear how it was used, even after reviewing the two interview guides (S2 Appendix). First, it may be helpful to describe more fully the nature of this framework and how it was used. That is, describe the fit between the framework and the interview guides. Presumably, RE-AIM was also considered when deciding who the participants would be in the current study. Some of the dimensions (e.g., implementation and maintenance; perhaps, adoption) are also pertinent to the implications of the research. Accordingly, it may be helpful to consider this framework in the Discussion section.

5. Participants (Results): Please include a brief description of the kinds of SMI experienced by the participants. Please note that the tables are incorrectly referred to on lines 154-155. That is, Table IA concerns the HCPs while Table 1B is client-focused.

It was also noted in the Methods that during the second half of the intervention, individual phone support was available as an adjunct to the monthly group sessions (line 99-100). It is recommended that information about the frequency of these contacts be described in this section or in Table IB. Was this type of support addressed by clients in the interviews? This is especially important given that HCPS recommended offering increased individual face-to-face support for some clients (see lines 318-321; see also lines 431-432). Again, was this recommendation fairly general or are there sub-groups of clients that would benefit from this support?

6. Results (Themes 1 and 2): The description of these themes seem to focus upon the experiences and perceptions of the majority of clients. The experiences of the minority, however, can be very pertinent – especially in considering the effectiveness of a program and steps to enhance the program. Accordingly, it may be helpful to describe some of the dissenting views. For example, it was stated that some participants wanted to gain more knowledge about lifestyle related issues (lines 174-175). What were the primary interests of the other clients? Did the interests seem to vary as a function of participant characteristics (e.g., gender, age, etc.)? The answers have help to refine and extend some of the recommendations made in the Discussion.

7. Discussion (appropriateness of a group-based intervention): On line 369, the authors state that “a group setting will not be ideal for all people with SMI …” Any thoughts as to who will benefit most from a group-based intervention?

8. Discussion (cognitive impairments): On line 382, it was acknowledged that many of the clients had cognitive impairments and that these impairments may be a barrier for successful change. What kinds of cognitive impairments? The nature of these impairments may lead to specific recommendations/procedures for addressing this potential barrier.

Comments related to the other specific Review Questions:

*2. Has the statistical analysis been performed appropriately and rigorously?

The described study uses qualitative methods and, as such, the issue of statistical analysis per se is not relevant. Having said that, it is important to consider the thematic analysis methods used. Overall, the methods used to analyze the transcripts and identify emerging themes were appropriate. In addition, member checking was conducted (lines 133-134) to help demonstrate credibility of the data and identified themes. Importantly, they had a strong response rate.

It was indicated that two members of the study team reviewed and coded each transcript (line 138). However, no information was provided about the consistency (or congruence) of the two sets of codes and how differences were resolved. It is recommended that a brief description of this process be included.

The statement on Line 141 regarding the validity of the themes was unclear. It is unusual to talk about the validity of qualitative data or themes, more generally.

*3. Have the authors made all data underlying the findings in their manuscript fully available?

No, some restrictions were identified. Specifically, the authors indicated that in response to “reasonable request[s],” the data will be made available from the corresponding author and with permission of the Vrije Universiteit Amerstdam.

Limited access to qualitative data is not unusual.

*4. Is the manuscript presented in an intelligible fashion and written in standard English?

Overall, the manuscript was clearly written in standard English. There were sections that were awkward such that it was hard to understand some of the points being made (e.g., lines 70-71, 137, 164, 171-172, 408-409). Careful proof-reading and editing will be sufficient to address this comment.

Reviewer #2: While I have expertise in severe mental illness and knowledge of qualitative methods, I do not use such methods in my work. Rather, I appreciate the approach in terms of its yield of underlying processes that are invisible in RCTs and quantitative approaches. This study did not disappoint as I found it very useful and informative. Note that I cannot judge the statistics other than recognizing that those described are used in qualitative studies. The lack of fully publically available data does not surprise me given confidentiality matters for clinical samples. The authors make it available under appropriate conditions, in my view.

In terms of suggestions to the authors, here is my list:

1) Abstract should be clear about the objectives so persons unfamiliar with SMILE will know what the study is about.

2) Extensive use of acronyms that are unexplained is problematic for clarity, e.g., what is FACT?

3) Explain more of the technical jargon, e.g., what is "process evaluation" exactly? Look for jargon and clarify meaning so the work is consumable by persons not steeped in qualitative methods.

4) The authors state that selection bias possibly occurred. Of course it occured, be clear that it did.

5) When describing themes, terms like most participants and some participants are frequent. I would suggest giving percentage to make things more concrete.

6) Address as a potential limitation that some participants attended a very small percentage of the 30 available sessions. What might be the impact or such.

7) Likewise, as a limitation concern, what are the potential implications that only 48% of the client interviewees "responded to the member check, and agreed with the summary". Why were they unresponsive at such a higher rate and does it degrade the contribution?

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Reviewer #1: Yes: Carolyn Szostak

Reviewer #2: No

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15 Jun 2022

We thank the reviewers for their positive comments and for the feedback on our manuscript. Please note that all lines mentioned in the responses are based on the 'Revised Manuscript with Track Changes' document when ''all markup'' under display tracking is enabled.

Review Comments to the Author

Reviewer #1:

Overall, I thought the research was well done and meaningful. I found the Introduction and Methods to be the weaker sections in that key aspects of the research were not always described clearly. The recommended revisions are relatively minor (that is, they should be easily achieved); however, they will substantively improve the quality of the manuscript.

RESPONSE: We thank the reviewer for these positive comments and for the feedback on our manuscript.

Concerns:

1. Focus of the intervention: It would be helpful to acknowledge the primary focus of the lifestyle intervention (i.e., weight loss, physical activity) in the Abstract (Objective; lines 23-26) and Introduction. This was not clear until S1 Appendix was examined. Although there were hints of the focus (e.g., line 38, “Irrespective of weight loss …; description of the inclusion criteria (i.e., line 122-23), for the most part, the description of the program within the body of the manuscript was quite vague. This is problematic in that the descriptor “lifestyle intervention” is vague. Such programs can be narrow or broad. In the case of more narrow foci, programs can vary tremendously. It is recommended that the final paragraph of the introduction (lines 80-93) be revised to include a brief description of the program’s main focus.

RESPONSE: Thank you for your comment. We agree that the current description is vague at certain places in the manuscript.

CHANGE: We added more information regarding the focus of the lifestyle intervention: in the abstract (lines 25-26), the introduction (lines 80-82) and the methods section (lines 110-113).

2. The described research is part of a process evaluation of the intervention that was conducted in parallel with a pragmatic cluster-randomized control trial of the SMILE lifestyle intervention. While the main study was cited, it is not clear if the process evaluation of the intervention has been published. Moreover, it was not clear why the authors decided to present the qualitative data in a separate manuscript. While this decision may well be appropriate, it would be helpful if additional information was included about the primary process evaluation in the Study Design section of the Methods (lines 96-105). For example, was this evaluation quantitative in nature? If it has been published, a reference for that article should be provided (see lines 84 and 86). In revising this section, please ensure that the various components of the study as a whole are clearly described. Also, it may be pertinent, in the Discussion, for the authors to address the inter-relationships between the results of the two parts of the process evaluation. Are the two sets of results complementary? Are there any discrepancies?

RESPONSE: The process evaluation was also qualitative in nature, however with a specific focus on the implementation process of the intervention, including a description of barriers and facilitators for effective implementation. As the present study and the process evaluation each have a different but complementary focus, and because it was impossible to summarize the wealth of information in one manuscript, we have prepared two different manuscripts.

CHANGE: The process evaluation of the study has recently been published, therefore we have added the reference of this publication when the process evaluation is mentioned in the manuscript. In addition, we explained the aim of the process evaluation (see also comment 3 from reviewer 2) in the introduction section (lines 84-86), in order to understand how the present study on the experiences of patients and health-care providers is related to the process evaluation. Finally, in the discussion (lines 459-462) we described the complementary relation of the process evaluation and the current article.

3. SMILE Intervention (lines 107-123): Please provide more information about the structure of the program. How long was each session? What was the size of the groups (i.e., clients and HCPs; this information was finally provided in the Discussion section (lines 422-423))? Describe the SMI inclusion criterion. Were individuals with co-morbid mental health disorders eligible to participate? While a list of topics covered in the program is available in S1 Appendix, it would be helpful to describe briefly the kinds of topics addressed in the body of the manuscript.

RESPONSE: For the inclusion of participants there was no distinction made between (co-morbid) mental health disorders in clients. All clients from participating FACT-teams were eligible to participate.

CHANGE: We added additional information regarding the SMILE intervention (lines 108 - 122), such as the timing of the sessions, group sizes, intervention topics and how many HCP’s were involved per session.

4. Use of RE-AIM framework: It was stated that the interview guides were based on the RE-AIM framework (Glasgow et al., 2019). While this framework is very pertinent, it was not clear how it was used, even after reviewing the two interview guides (S2 Appendix). First, it may be helpful to describe more fully the nature of this framework and how it was used. That is, describe the fit between the framework and the interview guides. Presumably, RE-AIM was also considered when deciding who the participants would be in the current study. Some of the dimensions (e.g., implementation and maintenance; perhaps, adoption) are also pertinent to the implications of the research. Accordingly, it may be helpful to consider this framework in the Discussion section.

RESPONSE: For the process evaluation and the current study on experiences of patients and professionals, the qualitative results were derived from the same data source (semi-structured interviews). Both articles are complementary to each other. We based the topics and interview guide on the RE-AIM framework which was explicitly used for the process evaluation to describe the process of implementation, including barriers and facilitators. In the analysis and writing of the current manuscript, the RE-AIM framework was no longer explicitly used, given its focus on experiences of clients and professionals with the lifestyle intervention. Therefore, we have not provided an extensive explanation of the RE-AIM framework and have not used it for data analysis and reporting for the current manuscript.

CHANGE: We have made some adjustments in the section Procedures to clarify the use of the RE-AIM framework in the two studies: the process evaluation and the current study on the experiences of clients and professionals.

The following sentences were added:

- The topics were based on the RE-AIM framework as this study was performed alongside the process evaluation which focused on the process of implementation of the intervention (Lines 143-145).

- These RE-AIM dimensions were incorporated throughout the interviews but were not explicitly used for the analysis of the data in the present study, given our focus on the experiences of clients and professionals (Lines 150-152).

5. Participants (Results): Please include a brief description of the kinds of SMI experienced by the participants. Please note that the tables are incorrectly referred to on lines 183-184. That is, Table IA concerns the HCPs while Table 1B is client-focused.

RESPONSE: We thank the reviewer for this comment. The global description of the psychiatric diagnoses can be found in Table 1B. We purposely did not further specify these diagnoses in order to ensure privacy of the clients, as HCPs know which of their clients was interviewed for the study.

CHANGE: We corrected the references for Tables 1A and 1B.

It was also noted in the Methods that during the second half of the intervention, individual phone support was available as an adjunct to the monthly group sessions (line 109-110). It is recommended that information about the frequency of these contacts be described in this section or in Table IB. Was this type of support addressed by clients in the interviews? This is especially important given that HCPS recommended offering increased individual face-to-face support for some clients (see lines 348-249; see also lines 418-419). Again, was this recommendation fairly general or are there sub-groups of clients that would benefit from this support?

RESPONSE: This is an interesting question. We agree that better insight into the telephone contacts could provide valuable information. Unfortunately, we were not able to collect reliable data on the use of those contacts, despite our efforts in this regard. In the interviews, the telephone contacts were not explicitly put forward as being valuable or not. Therefore, we cannot provide more information about this.

6. Results (Themes 1 and 2): The description of these themes seem to focus upon the experiences and perceptions of the majority of clients. The experiences of the minority, however, can be very pertinent – especially in considering the effectiveness of a program and steps to enhance the program. Accordingly, it may be helpful to describe some of the dissenting views. For example, it was stated that some participants wanted to gain more knowledge about lifestyle related issues (lines 206-207). What were the primary interests of the other clients? Did the interests seem to vary as a function of participant characteristics (e.g., gender, age, etc.)? The answers have help to refine and extend some of the recommendations made in the Discussion.

RESPONSE: We agree that when addressing ‘the majority’ on some views it seems we leave out views of the minority. We agree that this seems to make the information in the results section incomplete, as views from minorities of the participants are also of interest. When looking into our data again and when considering how we elaborated themes 1 and 2, we may conclude that no specific views of a minority of patients emerged from the data. The way we phrased some of the perspectives of respondents with respect to themes 1 and 2 were complete, given the available data. The fact that with respect to some (sub)themes a majority of respondents articulated their perspectives explicitly, this often means that other respondents did not verbalize their perspective in an explicit way. This is inherent to the qualitative method followed, using a semi-structured interview protocol and an iterative process of data-collection and data-analysis (see also our response to Reviewer 2).

That said, we were able to make some adjustments. We modified some sentences to clarify the above-mentioned aspects. Further, we added additional reasons participants mentioned to join the sessions, in addition to the most common reasons we already mentioned under theme 1. In the end, no clear dissenting views emerged from our data to report in the results section. Also, the analysis showed no clear relationship between participant characteristics and articulated perspectives for both theme 1 and 2.

CHANGE: We changed some phrasing of themes 1 and 2 in line with the above-mentioned clarification. In addition, we added some extra views for theme 1 regarding primary interests for joining the sessions (lines 208-210).

7. Discussion (appropriateness of a group-based intervention): On line 408, the authors state that “a group setting will not be ideal for all people with SMI …” Any thoughts as to who will benefit most from a group-based intervention?

RESPONSE: People who could benefit most from a group-based intervention are those who are looking for (new) social contacts, enjoy social activities or want to learn from peers.

CHANGE: We added the following sentence to the discussion section: In our opinion, people who could benefit most from a group-based intervention are those who are looking for (new) social contacts, enjoy social activities or are interested in learning from peers. (Lines 420-422).

8. Discussion (cognitive impairments): On line 395, it was acknowledged that many of the clients had cognitive impairments and that these impairments may be a barrier for successful change. What kinds of cognitive impairments? The nature of these impairments may lead to specific recommendations/procedures for addressing this potential barrier.

RESPONSE: We agree that it is important to specify the clients’ cognitive impairments in order to better apply procedures or recommendations to address this potential barrier. The data revealed that impairments in concentration were particularly mentioned.

CHANGE: We added this information in line 284(results) and line 395 (discussion).

Comments related to the other specific Review Questions:

*2. Has the statistical analysis been performed appropriately and rigorously?

The described study uses qualitative methods and, as such, the issue of statistical analysis per se is not relevant. Having said that, it is important to consider the thematic analysis methods used. Overall, the methods used to analyze the transcripts and identify emerging themes were appropriate. In addition, member checking was conducted (lines 158-160) to help demonstrate credibility of the data and identified themes. Importantly, they had a strong response rate.

It was indicated that two members of the study team reviewed and coded each transcript (line 163). However, no information was provided about the consistency (or congruence) of the two sets of codes and how differences were resolved. It is recommended that a brief description of this process be included.

CHANGE: We added additional information regarding this process in line 169-172.

The statement on Line 166 regarding the validity of the themes was unclear. It is unusual to talk about the validity of qualitative data or themes, more generally.

RESPONSE: We agree this is unusual. Instead of valid/validity we now used the words ‘credible/credibility’ as these terms are more common in qualitative research.

CHANGE: We adapted this sentence to: (4) reviewing whether themes credibly represent the data (lines 166-167).

*4. Is the manuscript presented in an intelligible fashion and written in standard English?

Overall, the manuscript was clearly written in standard English. There were sections that were awkward such that it was hard to understand some of the points being made. Careful proof-reading and editing will be sufficient to address this comment.

CHANGE: We have asked an English native speaker with experience with academic writing to edit the manuscript to make the article more clearly written in English. Several changes have been made throughout the manuscript.

Reviewer #2:

While I have expertise in severe mental illness and knowledge of qualitative methods, I do not use such methods in my work. Rather, I appreciate the approach in terms of its yield of underlying processes that are invisible in RCTs and quantitative approaches. This study did not disappoint as I found it very useful and informative. Note that I cannot judge the statistics other than recognizing that those described are used in qualitative studies. The lack of fully publically available data does not surprise me given confidentiality matters for clinical samples. The authors make it available under appropriate conditions, in my view.

RESPONSE: We thank the reviewer for these positive comments and for the feedback on our manuscript.

In terms of suggestions to the authors, here is my list:

1) Abstract should be clear about the objectives so persons unfamiliar with SMILE will know what the study is about.

RESPONSE: We agree this was unclear, therefore we adapted the aim description in the abstract.

CHANGE: We changed the objectives to make it more clear for people unfamiliar with SMILE (Lines 23-26).

2) Extensive use of acronyms that are unexplained is problematic for clarity, e.g., what is FACT?

CHANGE: We added the explanations for the acronyms FACT and SMILE to the manuscript.

FACT: Flexible Assertive Community Treatment

SMILE: Severe Mental Illness Lifestyle Evaluation

3) Explain more of the technical jargon, e.g., what is "process evaluation" exactly? Look for jargon and clarify meaning so the work is consumable by persons not steeped in qualitative methods.

RESPONSE: Thank you for your comment, we agree it is important to explain more technical jargon in the manuscript to make the work more accessible for people who are not steeped in qualitative methods.

CHANGE: We added explanations of the following technical jargon to the manuscript:

(1): Process evaluation (Lines 84-86, 101-102 and 458-463)

(2): Purposive sampling (Lines 129-137)

(3): Data saturation: (Lines 156-157)

4) The authors state that selection bias possibly occurred. Of course it occured, be clear that it did.

RESPONSE: We agree and changed this sentence in the discussion section.

CHANGE: We changed the sentence to: Therefore, it is plausible that selection bias has occurred. (line 471).

5) When describing themes, terms like most participants and some participants are frequent. I would suggest giving percentage to make things more concrete.

RESPONSE: Giving percentages or numbers is uncommon in qualitative research. As an iterative process is used, topics were adapted throughout the interview period, and new topics were added in subsequent interviews, based on information collected in previous interviews. It is possible that some (new) topics were not discussed in previous interviews as these topics were not addressed in those interviews but were in later interviews. In this qualitative research the exact quantity is not of primary concern, but we do give an indication to give an impression of bigger or smaller importance.

CHANGE: We believe it is opportune to provide exact quantitative figures in terms of percentages as this is uncommon for qualitative studies.

6) Address as a potential limitation that some participants attended a very small percentage of the 30 available sessions. What might be the impact or such.

RESPONSE: We purposely invited clients with a low attendance rate in the intervention to participate in the interviews to learn about their perspectives as well (this was done as part of the purposive sampling strategy, of which we have now added an explanation on lines 129-137). Learning the perspectives of participants with a low attendance is of interest as only interviewing people with a high attendance (who we assumed would be more satisfied with the intervention) will give one-sided views. Therefore, we do not believe this is a limitation of the study.

CHANGE: We believe it is not necessary to address this as a potential limitation as these participants were purposively added to the sample, as part of our purposive sampling strategy.

7) Likewise, as a limitation concern, what are the potential implications that only 48% of the client interviewees "responded to the member check and agreed with the summary". Why were they unresponsive at such a higher rate and does it degrade the contribution?

RESPONSE: Beforehand, for this population of clients with severe mental illness we did not expect a high response for the member checks. We were satisfied with the response rate of 48%. All member checks we received from clients mentioned that no changes were needed to the provided summary. However we do agree this might be a potential limitation.

CHANGE: We have added this as a limitation in the limitations section in the discussion (lines 474-476).

Submitted filename: 20220526 Response to Reviewers.docx

Click here for additional data file.

12 Jul 2022

Experiences and perceptions of people with a severe mental illness and health care professionals of a one-year group-based lifestyle programme (SMILE)

PONE-D-21-24557R1

Dear Dr. Walburg,

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: (No Response)

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

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3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: N/A

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4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: No

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

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6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: All major concerns have been addressed. I enjoyed reading the revised manuscript. It was very informative. However, there are a few minor revisions concerning writing that should be addressed.

1. On a number of occasions a word is preceded by a single quotation mark (i.e., '). There should be a closing quotation mark. See lines: 224, 392, 416, and 437.

2. Lines 81-82: the second clause of the sentence that starts, "The intervention was ..." is awkward and hard to follow. Please re-phrase.

3. Lines 119 and 121: HCPs and clients should be the possessive (i.e., HCPs' and clients'), respectively. Similarly, on line 362, "clients" should be the possessive and read, clients'.

4. Line 284: The sentence, "This change that was ..." is incomplete. Alternatively, omit "that" from the sentence.

5. The first sentence of the Strengths section is confusing (line 432). Given what follows, it seems that the first sentence should be descriptive of the current study.

6. Line 434: There should be a comma after "together".

With regards to the requirement to make all data full available (see Point 4), the authors provide an appropriate explanation for restricting access. Moreover, they have indicated that they will make it available under appropriate conditions.

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Reviewer #1: Yes: Carolyn Szostak, Ph.D.

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27 Jul 2022

PONE-D-21-24557R1

Experiences and perceptions of people with a severe mental illness and health care professionals of a one-year group-based lifestyle programme (SMILE)

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