Predictors of dream enactment behavior among medical students: The case of the University of Gondar, Ethiopia.

INTRODUCTION: Dream enactment behavior is one of the features of rapid eye movement sleep behavior disorder. It might be a manifestation of neurodegenerative diseases and can lead to fall associated injuries. There is no evidence of dream enactment behavior and its associated factors in Ethiopia. Hence, this study targeted to pinpoint the predictors of dream enactment behavior among Medical students at the University of Gondar.
METHODS: The cross-sectional survey was carried out at the University of Gondar among Medical students selected by simple random sampling technique from Dec 2020 to Feb 2021. We used a structured pretested questionnaire to collect the data and dream enactment behavior was evaluated using rapid eye movement sleep behavior disorder single question. Descriptive statistics were computed, and determinant factors were identified using binary logistic regression model. In the final model, explanatory variables with a p<0.05 were considered as predictors (statistically significant) of the dream enactment behavior. The strength of association was determined using adjusted odds ratio (AOR) with its 95% CI.
RESULTS: Four-hundred and twelve students took part in the study with 97.4% response rate. The mean age of participants was 20.82(±1.88) years and 291(70.63%) were males. The prevalence of dream enactment was 34.47% (95% CI: 30.02-39.20). Daytime sleepiness score (AOR = 1.104; 95% CI: 1.053-1.160), age (AOR = 1.15; 95% CI: 1.019-1.290), monthly pocket money (AOR = 0.9991; 95% CI: 0.9985-0.9997), alcohol drink (AOR = 2.71; 95% CI: 1.076-6.846), and perceived stress (AOR = 3.854; 95% CI: 1.802-8.242) were statistically significant factors of dream enactment behavior.
CONCLUSIONS: In this study, the magnitude of dream enactment behavior was high which was significantly associated with daytime sleepiness score, age, monthly pocket money, alcohol drink, and perceived stress all of which are modifiable except age. The University of Gondar has to plan a strategy to avert the condition via the prevention of the determinant factors. Students need to reduce stress and avoid alcohol drink. We strongly urge forthcoming scholars to ascertain association of dream enactment and academic performance of university students.

Introduction

Dreaming is a sleep related cognitive activity characterized by multisensory imagery, emotional arousal and apparent speech and motor activity [1]. Dream enactment behavior (DEB) is one of the manifestations of rapid eye movement (REM) sleep behavior disorders [2]. Dream enactor flails arms, leaps from the bed, or crawl [3]. REM sleep suppresses neurotransmitters such as serotonin, norepinephrine, and histamine which in turn contributes for dreaming [4].

Dream enactment behavior might lead to fall associated injury [5, 6], and is also an early manifestation of neurodegenerative diseases [7]. A nearly 70% of enacted dreams partake threats to the victims [8]. Nocturnal injury is common in REM sleep behavior disorders because of the acting out of dreams [9]. Contrary to this, there are studies illustrating DEB is not a bad phenomenon [10]. Dream enactment behavior could be due to partly by striatal changes in the dopaminergic pathways [11]. The knowledge of DEB is helpful to design intervention and prevention strategies for neurological disorders [12]. Moreover, it has imminent function to prevent α-synucleinopathy-related motor and cognitive decline [13] and to innovate therapeutic options for clinicians [14]. Evidences showed violent behavior during sleep exist in 1.6% among adults of whom 78.7% reported vivid dreams and 31.4% hurt themselves or someone else [15]. Behavioral management has promising effects for dream disorders [9].

Dream enactment behavior is associated with other sleep disorders (such as sleepwalking and sleep terror), family history of the condition [15], socioeconomic status [16], and distress [17]. Inconsistent findings were reported about the association of DEB and sex [18-20]. Elderly people are more affected by DEB [21]. People with narcolepsy, severe sleep deprivation, hormonal changes, age older than 50 years, drug users, alcohol drinkers, and individuals with neurodegenerative diseases are at higher risk of DEB [22].

In Ethiopia, there are studies on sleep quality [23], excessive daytime sleepiness [24], REM sleep behavior disorders [25], and insomnia symptoms [26] among University students. However, there is no previous study in Ethiopia yet on this topic. Hence, we envisioned to determine the prevalence of DEB and examine the determinant factors among Medical students at the University of Gondar. This study will be helpful to plan precautionary strategies by identifying associated factors so that students will be competent and academically productive.

Methods

Study area, design, and period

Institution-based cross-sectional survey was carried out from Dec 2020 to Feb 2021 at the University of Gondar, College of Medicine and Health Sciences, Northwest Ethiopia. University of Gondar is among the pioneer universities in Ethiopia serving the country since 1954. According to the statements written at the University website (www.uog.edu.et), currently the College of Medicine and Health Science has over 7,000 students and offers 22 undergraduate and 38 postgraduate programs.

Sample size and sampling technique

Sample size was determined using single population proportion formula with the following assumptions: proportion of dream enactment behavior (p = 0.5, no previous study), 95% confidence interval (CI), and 5% margin of error (d). The minimum sample size was 384 and after adding 5% non-response rate, we found a total of 423 samples. We applied simple random sampling technique to recruit study participants. The samples were from each year of study (from 1st year to final year) using proportional allocation by year of study. Over 1400 Medical students were enrolled in the same academic year of the data collection period.

Population

The source population was all undergraduate Medical students at the College of Medicine and Health Sciences. As described above, the facilitators enter to each class (in each year of students from year 1 to year 5). In each classroom the facilitators explained the purpose of the study. Then students were recruited by computer generated simple random sampling technique using excel spreadsheet. All medical students who came to the class during the data collection period were used as study population. We excluded students with severe illness (to avoid exhaustion) from the survey.

Data collection

Self-administered structured questionnaire was used to collect the required data for this study. The questionnaire comprised sociodemographic variables (sex, age in years, year of study, pocket money in Ethiopian birr), bedtime routines (Facebook use, coffee consumption, bathing, physical exercise, and alcohol drink), daytime sleepiness score, perceived stress (dichotomized), and the outcome variable (DEB). Two Postgraduate Psychiatry students served as facilitators after oriented about ethical issues and purpose of the study by the investigators.

Measurement of the study variables

We used a Single-Question Screen for REM sleep Behavior Disorder (RBD1Q) [27] which has only a single question, with two responses “Yes” or “No”. The participants were asked “Have you ever been told, or suspected yourself, that you appear to ‘act out your dreams’ while asleep such as flailing your arms in the air, punching, and running movements)? This tool is framed as better screening tool for epidemiological studies. Perceived stress scale (PSS-10) which was validated in Ethiopia for the assessment of stress [28] was used to measure stress. We used Epworth sleepiness scale to determine daytime sleepiness.

Data quality control

Careful processes were performed starting from the design of the questionnaire. Because the questionnaire was not validated in Ethiopia, we invited epidemiologists to assure the validity of the questionnaire and we finally used it after incorporating the comments from the experts. Pretest was done among 35 students at Maraki, one of the campuses of the University of Gondar. Finally, the facilitators strictly checked the filled questionnaire for completeness and consistency.

Statistical analysis

We entered the data using Epidemiological information version 7 and then exported into Stata 16 for data cleaning, recoding, and analysis. Normal distribution was checked using skewness and normality tests. For description of continuous variables, mean with standard deviation and range, as well as median and interquartile range (IQR) were computed. Frequency with percent was executed to describe categorical variables. Chi-square and t-tests were used to compare categorical and continuous variables, respectively, between students with DEB and non-DEB. Bivariable (at p<0.2) and multivariable (at p<0.05) binary logistic regression were performed to identify determinant factors of dream enactment. The degree of association was described using the adjusted odds ratio with 95% CI.

Ethical approval and consent to participate

Ethical approval was obtained from the Ethical committee of the School of Medicine, University of Gondar. Each participant gave written informed consent, and no identifiers were recorded.

Results

Descriptive characteristics of students by dream enactment behavior

A total of 412 students took part in the study with a response rate of 97.4%. Two hundred and ninety-one (70.63%) students were males, 160 (38.83) were first-year students, and 340 (82.52%) were orthodox Christian. We checked normal distribution for continuous variables, and we found that age, perceived stress score and Epworth sleepiness score were normally distributed whereas monthly pocket money was not normally distributed (right skewed). The mean age of participants was 20.82 (range: 18–34) years. The mean values of daytime sleepiness score and perceived stress score were 8.69 (±4.70) and 18.58(4.97), respectively. The median value of pocket money was 500 ETB (IQR = 2900).

Dream enactment behavior was higher in frequency among firs-year students (36.25%), males (36.08%). As observed from Table 1, 339(82.28%) participants reported the presence of perceived stress of which 133 (39.23) reported DEB. Twenty-six (6.31%) students drunk alcohol of which 16 (61.54%) had DEB. The chi-square and T-test results showed the association of DEB with age, perceived stress, daytime sleepiness score, and pocket money (Table 1).

Table 1

Descriptive characteristics by dream enactment behavior of Medical students of University of Gondar, Northwest Ethiopia, 2021.

Variables		Study sample (N = 412)	Dream enactment behavior		X2/t-test p-value
			No (%)	Yes (%)
Sex [f (%)]	Male	291 (70.63)	186 (63.92)	105 (36.08)	0.284
	Female	121 (29.37)	84 (69.42)	37 (30.58)
Study year [f (%)]	First-year	160 (38.83)	102 (63.75)	58 (36.25)	0.544
	≥Second	252 (61.17)	168 (66.67)	84 (33.33)
Religion [f (%)]	Orthodox	340 (82.52)	216(63.53)	124 (36.47)	0.342
	Protestant	37 (8.98)	32 (86.49)	5 (13.51)
	Muslim	26 (6.31)	17 (65.38)	9 (34.62)
	Others	9 (2.18)	5 (55.56)	4 (44.44)
Perceived stress [f (%)]	No (scored <15)	73 (17.72)	64 (87.67)	9 (12.33)	0.000
	Yes (scored ≥15)	339 (82.28)	206 (60.77)	133 (39.23)
Facebook use [f (%)]	No	158 (38.35)	102 (64.56)	56 (35.44)	0.742
	Yes	254 (61.65)	168 (66.14)	86 (33.86)
Alcohol drinks [f (%)]	No	386 (93.69)	260 (67.36)	126 (32.64)	0.003
	Yes	26 (6.31)	10 (38.46)	16 (61.54)
Age in years c, mean (SD), range		20.82 (1.88), 18–34	20.58 (1.70)	21.27 (2.12)	0.0004
Pocket money (ETB) c, mean (SD), range		684.7(507.6), 100–3000	750.6 (570.8)	559.5(324.6)	0.0003
Epworth sleepiness score c, mean (SD), range		8.69 (4.70), 0–24	7.80 (4.17)	10.34 (5.19)	0.000
Perceived stress score c, mean (SD), range		18.58 (4.97), 1–38	17.47 (4.76)	20.69 (4.69)	0.000

f = Frequency, c = continuous variable, ETB = Ethiopian birr, SD = Standard deviation.

The prevalence of dream enactment behavior among the participants was 34.47% (95% CI; 30.02–39.20) (Fig 1).

Fig 1

Magnitude of DEB among medical students at the University of Gondar, Northwest Ethiopia, 2021.

Predictors of dream enactment behavior among medical students

We conducted bivariable binary logistic regression at p<0.2 for all explanatory variables. From these, daytime sleepiness score, age of the respondent, monthly pocket money, coffee consumption and alcohol drink immediately before sleep, and perceived stress were associated with dream enactment behavior without adjustment to other variables. Then, we executed multivariable binary logistic regression analysis to adjust for other variables to eliminate the association due to chance at p<0.05. Of the candidate variables in the bivariable analysis, daytime sleepiness score, age, monthly pocket money, alcohol drink, and stress were statistically significant factors of dream enactment behavior (Table 2).

Table 2

The determinants of DEB using binary logistic regression model among medical students at the University of Gondar, Northwest Ethiopia, 2021 (N = 412).

Variables	Unadjusted	Adjusted
	OR (95% CI)	OR (95% CI)
ESSc	1.124(1.074–1.177)	1.104(1.053–1.160) ***
Age in yearsc	1.218(1.086–1.367)	1.146(1.019–1.290) *
Pocket money (ETB)c	0.9990(0.9984–0.9995)	0.9991(0.9985–0.9997) **
Coffee drink before sleep (Yes)	1.538(0.826–2.866)	0.860 (0.412–1.795)
Alcohol drink before sleep (Yes)	3.302(1.457–7.483)	2.71462(1.076–6.846) *
Perceived stress (Yes)	4.591(2.210–9.537)	3.854323(1.802–8.242) ***

ESS = Epworth sleepiness scale; c = Continuous; ETB = Ethiopian birr; OR = Odds ratio; bold fonts indicate statistically significant factors with dream enactment behavior

*significant at p<0.05

**significant at p<0.01

***significant at p<0.001.

A unit increases in daytime sleepiness score increases the odds of DEB by 10.4% (AOR = 1.104; 95% CI: 1.052–1.160). The odd of DEB is elevated by 14.7% (AOR = 1.146; 95% CI: 1.019–1.290) for a unit increase of age in years. Monthly pocket money is inversely associated with the occurrence of DEB in that a unit increase in monthly pocket money reduces DEB by 0.09% (AOR = 0.9991; 95% CI: 0.9985–0.9997). The odd of DEB is 2.71 times higher (AOR = 2.71; 95% CI: 1.076–6.846) among students who drink alcohol immediately before sleep compared to their counterparts. Students who reported perceived stress had 3.85 times (AOR = 3.854; 95% CI: 1.802–8.242) fold DEB compared to the references.

Discussion

Most people experience DEB at sleep time particularly during the REM sleep stage. Academic stressors could impose students to be stressed and have sleep disturbances. We examined the determinant factors of DEB among Medical students at the University of Gondar. To the best of our knowledge, this study is the first in its kind in Ethiopia. In this study, the prevalence of DEB was 34.47% (30.02–39.20) which was significantly associated with daytime sleepiness score, age of the participants, monthly pocket money, alcohol drink, and perceived stress level. The existence of DEB among university students may be caused partly due to academic associated anxiety and seep disruption [29]. This finding is higher than another study in Japan migraine patients [30] but lower than a study among university students in Canada (66%) [18]. The difference might be due to sample size, and the population of interest. The prevalence of DEB in our study is lower than studies among other population as observed in postpartum women (63%) and pregnant (40%) women [22] whereas our finding is far higher than studies in the general adult population (5.9% in men, and 4.1% in women), older adults (10.9%) [31]. This difference might be accounted for the varying activities of the population. In Ethiopia, there was a study among University students to determine REM sleep behavior disorder which was 46.25% [25]. This is higher than our finding. This might be because the current study was conducted among Medical students and the previous one was among health and medical students, besides, the tool was different.

The odd of DEB is elevated by 14.7% for a year increase in age. There is one study with similar finding [32]. As age increases, there will be increased daily stressful situations which might lead to dreaming in memorizing the daily activities and thoughts since dreaming is believed to be partly by the theory of biological response, organization of knowledge, activation-synthesis, and threat-simulation [33]. REM sleep behavior disorder is higher in older people which can increase the existence of DEB [34]. Monthly pocket money is inversely associated with the occurrence of DEB. Reports revealed that low socioeconomic status mediates the existence of stressors and hence higher income reduces DEB because students with high income may fulfill their economic needs that potentially prevent stress, anxiety, and depression [35].

A unit increase in daytime sleepiness score increases the odds of dream enactment behavior. This is supported by previous studies [30, 36]. This association might be because people chronically sleep deprived present higher scores for ESS, in turn, shorter latency for REM sleep, which increases the chance for DEB [37].

Though the numbers of people who drink alcohol were very small i.e 26 students, we found significant association between alcohol drink and DEB. The odd of DEB is 2.71 times among students who drink alcohol immediately before sleep compared to their counterparts which is in line with another study [38]. This might be because of the effect of alcohol on subsequent sleep disruption and fragmented sleep [39]. Besides, alcohol withdrawal associated-orexin gene reduction may lead to daytime sleepiness and hence DEB will occur during sleep at night [40]. Alcohol drink initially increases non-REM sleep by increasing gamma-amino butyric acid (GABA) and, later on, as the blood alcohol level drops off, REM sleep period increases and hence DEB elevates [41]. Students who reported perceived stress had 3.85 times folds DEB compared to the references. This is in line with other studies [42-44]. The association of stress with DEB is explained by the changes in cortisol hormone produced by the adrenal cortex. As a coping mechanism, cortisol is produced during stressful situations. In return, cortisol elevation plays a role to increase the content and nature of dreaming [45].

Even though few scholars argue the role of dreaming in memory consolidation [46], it is embarrassing and exerts bad health impact to the victims. This study establishes the need to institute screening of DEB among students and identifying the potential risk factors. Longitudinal studies are required to establish strong evidence on the associated factors of DEB and interventions has to be designed based on the findings. As a limitation, the tool used to determine the outcome variable is a screening instrument which cannot be used as a diagnostic modality. The cross-sectional survey did not infer cause-effect relationship.

Conclusions

In this study, the magnitude of DEB was high which was associated with modifiable factors except age. The University of Gondar needs to plan strategies to avert the condition via the prevention of the determinant factors such as launching protocols to restrict alcohol drink and reduce stress. Students must avoid alcohol drink immediately before sleep and reduce their stress level using different modalities. We strongly urge the forthcoming scholars to ascertain the association of DEB and academic performance of university students.

(DTA)

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18 Nov 2021

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Reviewer #1: PONE-D-21-16361

Title: Predictors of dream enactment behavior among Medical students: The case of the University of Gondar, Ethiopia

This manuscription is research about a cross-sectional survey that was carried out at the University of Gondar, Ethiopia, with medical students who was selected by simple random sampling technique. To evaluated dream enactment the authors used rapid eye movement sleep behavior disorder single question. They used a binary logistic regression model that after adjusted odds ratio, they found dream enactment behavior was high which was significantly associated with daytime sleepiness score, age, monthly pocket money, alcohol drink, and perceived stress all of which are modifiable except age.

We agree with the statistical test that author used, but I have some consideration.

1. Didn´t show results of normal distribution test.

2. Why did Bivariable (at p<0.2?) and multivariable (at p<0.05) binary logistic regression were use?

3. In case of perceived stress the data is not balance (17 versus 83 %). The same for alcohol drinks. It could be explained in the text.

4. Did the medical students at University of Gondar have sleep medicine class? It could influence the behavior of the student and it could be one of strategies to avert this condition.

The research results need to be better described, especially in relation to the distribution and unbalance in the number of cases for some variables. This could be one of the factors that may be masking the results. I suggest that this issue be addressed by the authors so that the manuscript can be in a format for publication.

Reviewer #2: Review of paper: Predictors of dream enactment behavior among Medical students: The case of the University of Gondar, Ethiopia

PlosOne

Overview: this is a very interesting study aiming to evaluate the prevalence of dream enacting behavior (DEB) on the Medical students population from an university of Ethiopia. Furthermore, authors also investigated the predictors of DEB by means of binary logistic regression models and calculated the OR for significant predictors. Their findings indicate a moderate prevalence (34%) of DEB on the population. Similar prevalence has been described elsewhere. Interesting, they also found associations between stress (the higher, the worse), money pocket (the less, the worse), and sleepiness (the higher, the worse) with the prevalence o DEB. In my opinion this is a well conducted experiment, very well written with interesting results. The most important thing I wish authors to discuss a bit more is why they chose to use only a single question for DEB instead of a classic questionnaire (REM sleep behavior disorder screening questionnaire, for example) for a better screening of DEB? I am questioning this because authors decided to include the Epworth Sleepiness Scale (which has no validation for their country).

Major

Methods

Sampling: authors described that a “simple random sampling technique” was applied. I understand it, however, I would like to know better about the recruitment process. How were participants recruited to take part into the survey? At line 90 page 4 there is a statement “Students who were present at the time of data collection were included in the study”. I apologize, but I could not understand what authors mean with “student who were present”. Present where? This is related to the recruitment process already mentioned.

Data Quality control: since author mentioned a quality control procedure, I am wonder how the consistency was determined by the facilitators?

Dream enactment behavior assessment: author assessed DEB by means of a single question. Also, authors claimed that this is a “betters screening tool for epidemiological studies”. Could authors provide a comparison between their question and other tools for assessing REM-sleep behavior disorders, or just DEB?

Results:

It was a bit surprising to see that over 70% of the sample is male. Could authors provide an explanation for it? Is it related to the willing to take part into the study, or is it representative of the university students’ population?

Discussion:

page 8 lines172, 173: I do not agree with the assumption that REM sleep increases in magnitude as a function of age. It is well known that REM sleep is reduced as people get old. Please, investigate Li et al 2018. Sleep in Normal Aging. Sleep Med. Clin.

Page 9 lines 178-180: I think authors went a bit too far to explain the association between sleepiness and their findings on DEB. Perhaps a simpler explanation would be that people chronically sleep deprived present higher scores for ESS, in turn, shorter latency for REM sleep, which increases the chance for DEB.

Also, I missed a discussion about the prevalence of DEB on their population in comparison to others. I would suggest authors to explore a bit more the review (already cited) from Baltzan et al 2020. There is research on REM-sleep behavior disorder that must be discussed in this manuscript.

Finally, I would be a bit more conservative on interpreting their findings from alcohol consumption since only 26 participants declared to drink. Authors should acknowledge this when discuss this finding.

Minor

Introduction:

At page 3 line 62 “However, there is another study where sex is insignificant”. I think authors mean that sex is not significantly associated. I would not say “insignificant”. Furthermore, there is a typo, perhaps authors mean “are” instead of “is”.

Methods:

Ethics: It is very clear the ethical statement at the checklist, but I would advise authors to include similar statement on ethical approval and written informed consent by participants at the methods section.

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Reviewer #1: Yes: John Fontenele Araujo

Reviewer #2: Yes: Felipe Beijamini

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16 Dec 2021

Point-by-point responses to the academic editor and reviewers

MS ID: PONE-D-21-16361

Title: Predictors of dream enactment behavior among Medical students: The case of the University of Gondar, Ethiopia

We are very grateful for giving us the chance for the revision and improvement of our manuscript. All the authors involved in the revision process and we hope we addressed all the raised issues. The changes we made are marked red in the revised manuscript.

Academic editor’s comments

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming.

Authors’ reply: Thank you. We assured that we fulfill the PLOS ONE’s requirements.

2. In your Data Availability statement, you have not specified where the minimal data set underlying the results described in your manuscript can be found.

Authors’ reply: Thank you. We included a statement describing the minimal dataset in the revised manuscript. We also uploaded the study’s minimal data set. This is described in the cover letter.

3. Please amend the manuscript submission data (via Edit Submission) to include author Yigizie Yeshaw.

Authors’ reply: We amended as suggested.

4. Your ethics statement should only appear in the Methods section of your manuscript. If your ethics statement is written in any section besides the Methods, please move it to the Methods section and delete it from any other section. Please ensure that your ethics statement is included in your manuscript, as the ethics statement entered into the online submission form will not be published alongside your manuscript.

Authors’ reply: We relocated the Ethics statement from the declaration to the Methods section as recommended.

Authors’ reply to Reviewer #1: PONE-D-21-16361

This manuscription is research about a cross-sectional survey that was carried out at the University of Gondar, Ethiopia, with medical students who was selected by simple random sampling technique. To evaluated dream enactment the authors used rapid eye movement sleep behavior disorder single question. They used a binary logistic regression model that after adjusted odds ratio, they found dream enactment behavior was high which was significantly associated with daytime sleepiness score, age, monthly pocket money, alcohol drink, and perceived stress all of which are modifiable except age.

We agree with the statistical test that author used, but I have some consideration.

1. Didn´t show results of normal distribution test (line 134-137)

Authors’ reply: Thank you very much. Sorry for not including in the results section. We actually conducted normal distribution test before the start of the overall analysis. Monthly pocket money was not normally distributed (right skewed) whereas age, perceived stress score and Epworth sleepiness score were normally distributed. We included this in the revised manuscript.

2. Why did Bivariable (at p<0.2?) and multivariable (at p<0.05) binary logistic regression were use?

Authors’ reply: Thank you. In the first phase of the binary logistic regression (bivariable analysis) we checked the crude association between the outcome variable (DEB) and each single independent variable. To avoid possible elimination of important variables (statistically), we used a p<0.2 as cut-off value. Those variables with a p<0.2 were candidates and entered into the multivariable logistic regression analysis. Finally, as a common recommendation of statisticians we used a p<0.05 as cut of point (in the multivariable regression) to decide statistical significance of each variable by keeping other variables constant.

3. In case of perceived stress the data is not balance (17 versus 83%). The same for alcohol drinks. It could be explained in the text.

Authors’ reply: Thank you. We calculated the percent (%) in table 1 as; for the first column (total), we calculated percentages for column (column %) e.g. for stress from the total of 412 students 133 (39.23%) had stress. For the next columns, the percent was calculated as row %. As observed here, 339(82.28%) participants reported the presence of perceived stress of which 133 (39.23) reported dream enactment behavior. The same works for alcohol drink and other variables. Twenty-six (6.31%) students drunk alcohol of which 16 (61.54%) had DEB.

4. Did the medical students at University of Gondar have sleep medicine class? It could influence the behavior of the student and it could be one of strategies to avert this condition.

Authors’ reply: Thank you. As you describe sleep medicine class affects the behavior of students but there is no such course in the curriculum of medicine for undergraduate program in this university. However, students when they are in the first year of their study, they may took sleep physiology which we believe all students took it. Therefore, we expect equal course delivery regarding sleep physiology and all the included departments attended physiology course because it is given in the first semester of the first year of their study period.

The research results need to be better described, especially in relation to the distribution and unbalance in the number of cases for some variables. This could be one of the factors that may be masking the results. I suggest that this issue be addressed by the authors so that the manuscript can be in a format for publication.

Authors’ reply: Thank you. We explored all the texts for the mismatch with the values in the table and we made corrections accordingly in the revised manuscript.

Authors’ reply to Reviewer #2:

Overview: this is a very interesting study aiming to evaluate the prevalence of dream enacting behavior (DEB) on the Medical students population from an university of Ethiopia. Furthermore, authors also investigated the predictors of DEB by means of binary logistic regression models and calculated the OR for significant predictors. Their findings indicate a moderate prevalence (34%) of DEB on the population. Similar prevalence has been described elsewhere. Interesting, they also found associations between stress (the higher, the worse), money pocket (the less, the worse), and sleepiness (the higher, the worse) with the prevalence of DEB. In my opinion this is a well conducted experiment, very well written with interesting results. The most important thing I wish authors to discuss a bit more is why they chose to use only a single question for DEB instead of a classic questionnaire (REM sleep behavior disorder screening questionnaire, for example) for a better screening of DEB? I am questioning this because authors decided to include the Epworth Sleepiness Scale (which has no validation for their country).

Authors’ reply: Thank you very much for the kind appreciation of our topic and the way we describe. We tried to address all the comments raised as follows.

Reviewer’s concern: Major

Methods

Sampling: authors described that a “simple random sampling technique” was applied. I understand it, however, I would like to know better about the recruitment process. How were participants recruited to take part into the survey? At line 90 page 4 there is a statement “Students who were present at the time of data collection were included in the study”. I apologize, but I could not understand what authors mean with “student who were present”. Present where? This is related to the recruitment process already mentioned.

Authors’ reply: Thank you very much for raising this issue. We already did it but we didn’t included in the previous version of our manuscript. It gives sense if included in the manuscript which persuaded as to agree with the comment and hence we included the following in the revised manuscript. “As described above, the facilitators enter to each class (in each year of students from year 1 to year 5). In each class room the facilitators explained the purpose of the study. Then students were recruited by computer generated simple random sampling technique using excel spreadsheet”. Sorry for creating confusion by “those who were present”, by this we mean that “All medical students who came to the class during the data collection period were used as study population”. All this are detailed in the revised manuscript.

Data Quality control: since author mentioned a quality control procedure, I am wonder how the consistency was determined by the facilitators?

Authors’ reply: Thank you. The facilitators checked completeness and consistency. By consistency, we mean that facilitators checked the records of students if there were illogical records. E.g. a student may fill his age as 119 mistakenly to write 19 and so on. Another thing is students who responded “No” to “I have or had the following phenomena during my dreams” may list the activities which we expect to be empty. Therefore, facilitators were responsible to check such issues.

Dream enactment behavior assessment: author assessed DEB by means of a single question. Also, authors claimed that this is a “betters screening tool for epidemiological studies”. Could authors provide a comparison between their question and other tools for assessing REM-sleep behavior disorders, or just DEB?

Authors’ reply: REM Sleep Behavior Disorder Single-Question Screen (RBD1Q), a screening question for dream enactment with a simple yes/no response with a sensitivity of 93.8% and a specificity of 87.2% (as reported by Ronald B Postuma et al 2012) which are comparable to other REM screening tools with longer questionnaires. That is why this instrument is considered as better epidemiological tool.

Results: It was a bit surprising to see that over 70% of the sample is male. Could authors provide an explanation for it? Is it related to the willing to take part into the study, or is it representative of the university students’ population?

Authors’ reply: The high number of males in our study is due to the large proportion of male medical students in the university. This could be due to in Ethiopian context, joining medical schools usually requires being academically top scorer and due to other social burdens beyond academic duties (helping their family etc) female students may not get a chance to join medical schools. That is why we have less number of female participants.

Discussion:

page 8 lines172, 173: I do not agree with the assumption that REM sleep increases in magnitude as a function of age. It is well known that REM sleep is reduced as people get old. Please, investigate Li et al 2018. Sleep in Normal Aging. Sleep Med. Clin.

Authors’ reply: Thank you very much. We looked into the given reference and other related articles as well. We agree that REM sleep time (normal REM period) is reduced as people get old but the NREM sleep increases as the person gets older especially in the adult population. When we look at the abnormal REM i.e. REM sleep behavior disorder, it increases as people get older. Older people have higher rate of REM sleep behavior disorder. In the revised manuscript we described as REM sleep disorder. We then revised the discussion accordingly.

Page 9 lines 178-180: I think authors went a bit too far to explain the association between sleepiness and their findings on DEB. Perhaps a simpler explanation would be that people chronically sleep deprived present higher scores for ESS, in turn, shorter latency for REM sleep, which increases the chance for DEB.

Authors’ reply: Thank you very much for the compliment. We included the statement as suggested.

Also, I missed a discussion about the prevalence of DEB on their population in comparison to others. I would suggest authors to explore a bit more the review (already cited) from Baltzan et al 2020. There is research on REM-sleep behavior disorder that must be discussed in this manuscript.

Authors’ reply: Thank you very much. We included the recommended statements in the revised manuscript.

Finally, I would be a bit more conservative on interpreting their findings from alcohol consumption since only 26 participants declared to drink. Authors should acknowledge this when discuss this finding.

Authors’ reply: Thank you very much. We included the following statement in the discussion section before we discussed the odds of alcohol drink to give clue about the small observations of alcohol drink to the audiences “Though the numbers of people who drink alcohol were very small i.e 26 students, we found significant association between alcohol drink and DEB.”.

Minor

Introduction:

At page 3 line 62 “However, there is another study where sex is insignificant”. I think authors mean that sex is not significantly associated. I would not say “insignificant”. Furthermore, there is a typo, perhaps authors mean “are” instead of “is”.

Authors’ reply: Thank you. Regarding sex, we merged it with previous statement as “there were inconsistent findings about the association between DEB and se then we listed the references. We check all the typos errors and we hope we improved the revised manuscript.

Methods:

Ethics: It is very clear the ethical statement at the checklist, but I would advise authors to include similar statement on ethical approval and written informed consent by participants at the methods section.

Authors’ reply: Thank you very much. The editor advised us to relocate the ethics statement into the methods section. And hence, we relocated the ethics stamen into methods section.

Submitted filename: Authors Response to Reviewers.docx

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31 Jan 2022

Predictors of dream enactment behavior among Medical students: The case of the University of Gondar, Ethiopia

PONE-D-21-16361R1

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Reviewer #1: The authors answer all questions and the manuscript is in publication format. Then I agree that the manuscript is accepted

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There is only a typo at line 140 page 6. It is written “firs-year”.

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Reviewer #1: Yes: John F Araujo

Reviewer #2: Yes: Felipe Beijamini

15 Feb 2022

PONE-D-21-16361R1

Predictors of dream enactment behavior among Medical students: The case of the University of Gondar, Ethiopia

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