Recreational drug use among Nigerian university students: Prevalence, correlates and frequency of use.

BACKGROUND: Given the paucity of data on recreational drug use and the recent media attention on the abuse of drugs such as codeine cough syrups and tramadol, in Nigeria, our study examined the prevalence and frequency of recreational drug use among young adults from two Nigerian universities. We drew from the Socio-ecological Model to examine the influence of factors at the individual and family level on recreational drug use among adolescents and young adults.
METHODS: This cross-sectional study was conducted between February and March 2018 among a final sample of 784 male and female university students selected using stratified random sampling. Binary logistic regression was used to identify significant predictors of ever use and current use of drugs.
RESULTS: Our analyses showed that 24.5% of students had ever used drugs for recreational purposes, and 17.5% are current users. The median drug use frequency over the past month was six days among current users (n = 137). In the multivariable analyses, living in the same household as one's mother (AOR 0.28 95% CI 0.16-0.49), adequate family support (AOR 0.48 95% CI 0.26-0.89) and frequent attendance of religious fellowships (AOR 0.13 95% CI 0.07-0.25) were significantly associated with a lower likelihood of recreational drug use. However, male sex (AOR 1.52 95% CI 1.05-2.21) was associated with higher odds of recreational drug use.
CONCLUSION: The family should be considered as an important unit to sensitize young people on the harmful effects of drug use. It is also vital that religious leaders speak against drug use in their various fellowships. There is a need to address recreational drug use on Nigerian campuses by educating students about its adverse impacts.

Background

The illicit use of drugs for recreational purposes or for eliciting intoxicating effects has been recognised to be a growing and burdensome public health issue particularly among young adults in high-income countries [1-3] and recently in developing countries [4-7]. The global deaths caused directly by the use of illicit drugs have increased by 60% from 105,000 deaths in the year 2000 to 168,000 deaths in 2018 [8]. The adverse effects of drug abuse include non-communicable diseases, cardiovascular and central nervous system collapse [9], addiction [10], mental health issues [11, 12], accidents [13], involvement in criminal activity [14] and risky sexual behaviours [15, 16]. Also, mental health disorder among youths aged 10–24, which accounts for about 2% of global deaths, has been linked to illicit drug use [17]. Cannabis use can affect school performance [18], especially in mathematics. Heavy and regular marijuana use during teenage years can result in an 8-point reduction in Intelligence Quotient (IQ) [19].

According to the United Nations Office on Drugs and Crime (UNODC), Nigeria is one of the current highest consumer of cannabis and amphetamine in Africa [8]. Nevertheless, studies on recreation drug use in Nigeria are scarce and exitsing studies have focused on high school students and mostly on the use of alcohol. Also, most of the studies focus on the role of individual-level factors and peer influence. There is, however, a paucity of studies examining the influence of family/household-level and social factors on recreational drug use among adolescents and young adults in Nigeria. Our study fills this gap by examining the drug use prevalence and frequency as well as the role of family/household-level and social factors on recreational drug use among adolescents and young adults.

Theoretical underpinning

We drew from the socio-ecological model (SEM) [20] to understand the role of family/household-level and social factors on recreational drug use among adolescents young adults. The SEM has proven to be an instrumental theoretical framework for addressing several youth development outcomes. The SEM posits that youth behaviours are not influenced only by their individual (intrapersonal) characteristics but by other factors in their environment which could be at the family, school, peer, community and national level. This model assumes that interactions between youth and different levels are mutual as they both influence each other.

The socioecological model postulates that the family is a child’s early microsystem for learning how to live and about the real world. The influence of the family is strong in the life of a child. It provides the nurturing centrepiece for the child. One mechanism through which the family influences young peoples drug use may be through living arrangements and parental monitoring. The age of adolescence is a transition phase, and the presence of parents leaves a permanent influence that is crucial for the development of youth. The family instils norms and values in a child through constant training, control and monitoring, which is also dependent on the household living arrangement. The family norms and values instilled from childhood to adolescence period will continue to influence the behaviour of young people even until their adulthood. There is evidence that youths with a higher level of parental monitoring have lower odds for risky behaviours [21].

Based on SEM, family structure, living arrangement, and family support could influence young people's use of drugs. A study has shown that higher parental education and income are associated with marijuana use in the United States [22]. We, therefore, posit that adequate family support will be associated with reduced odds of recreational drug use among adolescent and young adults in Nigeria.

Living in one's parent household may influence the amount of time spent with the child and may also influence closeness to the child that may continue even when the youth leaves the home. Individuals who did not live with their parents due to deaths or divorce may have missed out on some of the critical parental lessons capable of shaping their later life behaviours. The effect of living in the same household as one's parent on drug use has never been investigated in the Nigerian context. Our study proposed that living in the same household as one's parent will reduce the odds of drug use among young people even when they are in universities.

Religion is also a microsystem factor that could impact illicit drug use among adolescents and young adults. Religion teaches codes of ethical behaviours and forbids the use of illicit drugs. As such, we posit that frequent attendance of religious fellowships will be associated with a lower likelihood of illicit drug use among young Nigerian adults in Nigeria.

The socioecological model also illustrates the impact of meso, exo and macrosystems on the development of a child. However, our focus in this study is limited to the impact of microsystem factors such as the family and religion in understanding young people’s illicit drug use.

Methods

Study design

The data analysed in this study came from a more extensive study, which assessed the sexual health of university students in Nigeria. Full details of the methodology have been published elsewhere [23-25]. This descriptive cross-sectional study was conducted among male and female university students in two Nigerian universities between February and April 2018. The two universities, one owned by the state government and the other owned by the federal government, were selected purposively. A self-designed questionnaire was administered to 800 consenting male and female students through face-to-face interviews. A pilot study was conducted among 20 demographically matched students in another university, and feedback was obtained to improve the questionnaire. Experienced research assistants who were trained purposively for this study conducted the interviews.

Participants and sampling

The study participants were male and female students of the two selected universities. The population of students in both universities was about 45,000. Participants were selected using stratified random sampling. Stratification was based on sex, level of study, and course of study. Only undergraduate students were included in the study. For representativeness, the estimated sample size was 384 students per university. This was determined using the sample size calculator, at a 95% confidence level, ±5 margin of error. However, 400 students were selected per university after adjusting for possible incomplete responses. Overall, 800 male and female students took part in the study; however, only 784 questionnaires were returned with complete responses.

Ethical statement

All participants provided written consent, and the rights of participants to privacy, anonymity, and confidentiality were maintained throughout the study. The University of Fort Hare and Ondo State ethical review committees approved the study protocol. We provided students under age 18 years with an additional parental/guardian consent form to complete. The students were given a week to obtain their parent/guardian's consent to participate in the study. About 56 under-18 students who took part in the study obtained their parent or guardian's consent and also assented to participate in the study.

Dependent variables

The main outcome variable was a two-category (yes/no) nominal measure of recreational drug use. Participants were asked: "Have you ever used substances/drugs like Codeine, Marijuana, Tramadol for pleasure, or to ease tension/stress?" To estimate the recent use of drugs for recreation, we asked participants: "Do you currently use substances/drugs like Codeine, Marijuana, Tramadol for pleasure, or to ease tension/stress? To understand the frequency of recreational drug use, we asked participants to state the number of days they have used recreational drugs in the past 30 days. We did not ask questions on specific drugs, which has been noted as a limitation of this study.

Independent variables

Our variable selection was informed by the SEM [20]. We included individual-level characteristics, such as age and gender. Age was measured by asking participants to indicate their age at their last birthday. We later categorised these ages into a categorical variable for bivariate and multivariable analyses. Also, participants were asked to indicate their gender.

Based on the SEM propositions, family/household factors are important microsystem predictors of health outcomes [20]. We included several family factors, such as family structure, family support, death of parents, and living with parents in this study. Family structure was measured by asking participants to describe their family type. We provided four categories for participants to choose from, which include nuclear family (two-parent family), single-parent family, polygamous family (mother having a co-wife), and foster family (residing with uncles, aunties, grandmother or father).

Family support was measured by asking participants to rate the level of support they receive from their parents. Responses were categorised as adequate support, moderate support, insufficient support, and no support. Our operationalisation of family support substituted for family wealth. We note that it is perhaps not only the amount of money a child receives from home that matters but also how the child perceived the money to be sufficient to meet their needs or not. As such, we asked participants to consider the support they get from their family in totality, that is, including support beyond money. Also, we used the term family support loosely given that some students were orphans. Thus, they could reference the support they received from their guardians as family support. Financial support is important for students, given that a majority of them depend heavily on their parents for university tuition fee and other living expenses. Thus, the lack of financial support means that students feel unsupported. However, it is important to note that in rare cases, parents could provide adequate financial support but less emotional support. Overall, our question is mostly an indication of how participants perceived the level of support they receive from their parents. Rather than a measure of monetary value, perceived parental support is an indication of the value students attribute to the support (both financial and beyond) they receive from their parents.

We also asked participants whether their parents are alive and if they live with their parents when not in school. Responses were a binary choice of "yes" or "no".

Another microsystem factor we considered in this study that could potentially influence young people's drug use for recreational drug use is religion. We asked participants to indicate their religion from a list containing the main religious groups in Nigeria. Participants' religious affiliation was classified as Christian- Orthodox, Christian-Pentecostal, and Muslim. We further asked participants about their frequency of attendance of religious fellowships. We provide five options, which include every day, twice a week, once a week, once a month, and once a year. We classified those who attended religious gatherings every day and at least twice a week as frequent attendants, those who attended once a week as moderate attendants, and those who attended once a month or in a year as low attendants.

Statistical analysis

The data generated through the questionnaires were coded and captured into the Statistical Package for the Social Sciences (IBM SPSS Statistics Version 24). Data were cleaned for possible data entry errors. Descriptive statistics were used to summarise all variables of interest. Frequency counts and percentages were computed. Mean, median, and standard deviation were calculated for continuous variables. Unadjusted binary logistic regression model was used to examine the effect of each individual level factors, family/hosuehold factors, and religion on having ever used drugs and current use of drugs for recreational purposes. Adjusted binary logistic regression model was used to examine the predictors of drug use among the students. 95% confidence intervals were estimated for each odds ratio. All p-values less than 0.05 were considered statistically significant.

Results

The median age of study participants was 22 years. The demographic characteristics of the study participants are presented in Table 1. Most participants were aged 24 years and below (66.9%), resided off campus (80.1%), from a nuclear family (58.2%), and received adequate support from home (70.9%).

Table 1

Sociodemographic and family characteristics of study participants by gender.

Variables	All participants	Male	Female
All participants	784 (100)	402 (51.3)	382 (48.7)
Age
Below 20 years	219 (27.9)	76 (18.9)	143 (37.4)
20–24 years	384 (49.0)	207 (51.5)	177 (46.3)
Above 24 years	181 (23.1)	119 (29.6)	62 (16.2)
Residence Type
University residence	156 (19.9)	61 (15.2)	95 (24.9)
Off campus residence	627 (80.1)	340 (84.8)	287 (75.1)
Living arrangement
I live alone	237 (30.7)	116 (29.4)	121 (31.9)
Live with one room mate	315 (40.8)	161 (40.9)	154 (40.6)
Have more than one roommate	221 (28.6)	117 (29.7)	104 (27.4)
Religious Background
Christian orthodox	304 (38.9)	166 (41.3)	138 (36.3)
Christian Pentecostal	270 (34.5)	131 (32.6)	139 (36.6)
Muslim	208 (26.6)	105 (26.6)	103 (27.1)
Father alive
Yes	654 (83.4)	328 (81.6)	326 (85.3)
No	130 (16.6)	74 (18.4)	56 (14.7)
Live in the same household as your father
Yes	567 (82.3)	277 (78.9)	290 (85.8)
No	122 (17.7)	74 (21.1)	48 (14.2)
Mother alive
Yes	700 (89.5)	353 (88.0)	347 (91.1)
No	82 (10.5)	48 (12.0)	34 (8.9)
Live in the same household as your mother
Yes	642 (89.4)	315 (85.8)	327 (93.2)
No	76 (10.6)	52 (14.2)	24 (6.8)
Family type
Single-parent family	199 (25.5)	124 (31.0)	75 (19.7)
Nuclear family	454 (58.2)	212 (53.0)	242 (63.7)
Polygamous family	90 (11.5)	49 (12.3)	41 (10.8)
Foster family	37 (4.7)	15 (3.8)	22 (5.8)
Family support
Adequate	555 (70.9)	263 (65.6)	292 (76.4)
Moderate	167 (21.3)	105 (26.2)	62 (16.2)
Insufficient	44 (5.6)	24 (6.0)	20 (5.2)
No support	17 (2.2)	9 (2.2)	8 (2.1)

Recreational drug use

About a quarter of the students had ever used substances/drugs like Codeine, Marijuana, and Tramadol for recreational purposes and the proportion varied by age (16–19 years; 18.0%, vs 20–36 years; 27%), sex (male; 29.6%. vs female; 19.2%), and family support (two-parent family 19.7% vs other family types 30.8%).

The results of the unadjusted and adjusted logistic regression are presented in Table 2. In the unadjusted logistic regression model, sex, age, living with the father, mother alive, living with the mother, family structure, family support, religious affiliation and higher frequency of religious attendance (at least twice a week) were significantly associated with having ever used drugs for recreational purpose. In the adjusted model, only being a male, living with the mother, family support, Christian -orthodox religious affiliation, and frequent attendants of religious fellowships remained significantly associated with having ever used drugs for recreational purposes. Students who live in the same household as their mothers had lower odds of having ever used drugs for recreational purposes compared with those who did not. Students who receive adequate family support were 52% less likely to have ever used drugs for recreational purposes compared with those who received insufficient or no support. Christian-orthodox religious affiliation was associated with a lower likelihood of drug use for recreational purposes, with students who attended orthodox churches being 43% less likely to use drugs for recreational purposes compared with those who were Muslims. Also, those who attended religious services at least twice a week were 87% less likely to have ever used drugs for recreational purposes compared with those who attended only once a month or a year.

Table 2

Multivariable analysis showing predictors of ever use drugs for recreational purposes among university students.

Variables	Yes n (%)	No n (%)	Unadjusted Odds Ratio (95% CI)	Adjusted Odds Ratio (95% CI)
All participants	191 (24.5)	589 (75.5)
Gender
Male	118 (29.6)	281 (70.4)	1.77 (1.27–2.47)*	1.52 (1.05–2.21)*
Female (Ref)	73 (19.2)	308 (80.8)	1	1
Age
Below 20	39 (18.0)	178 (82.0)	0.59 (0.40–0.88)*	0.69 (0.44–1.07)
20 and above (Ref)	152 (27.0)	411 (73.0)	1	1
Father alive
Yes	153 (23.5)	498 (76.5)	0.74 (0.48–1.12)	0.97 (0.54–1.77)
No (Ref)	38 (29.5)	91 (70.5)	1	1
Live in the same household as father
Yes	123 (21.8)	442 (78.2)	0.43 (0.28–0.65)***	0.77 (0.47–1.29)
No (Ref)	48 (39.3)	74 (60.7)	1	1
Mother Alive
Yes	157 (22.5)	540 (77.5)	0.42 (0.26–0.68)***	1.77 (0.88–3.57)
No (Ref)	33 (40.7)	48 (59.3)	1	1
Live in the same household as mother
Yes	125 (19.5)	515 (80.5)	0.18 (0.11–0.30)***	0.28 (0.16–0.49)***
No (Ref)	43 (57.3)	32 (42.7)	1	1
Family Types
Nuclear	89 (19.7)	362 (80.3)	0.55 (0.40–0.77)***	0.90 (0.58–1.38)
Single parent/polygamous/foster care (Ref)	100 (30.8)	225 (69.2)	1	1
Family Support
Adequate/moderate support	160 (22.0)	559 (77.7)	0.29 (0.17–0.49)***	0.48 (0.26–0.89)*
No or insufficient support (Ref)	30 (50.0)	30 (50.0)	1	1
Religious affiliation
Christian-Orthodox	66 (21.7)	238 (78.3)	0.63 (0.42–0.95)*	0.57 (0.37–0.90)*
Christian-Pentecostal	62 (23.0)	208 (77.0)	0.68 (0.45–1.02)	0.74 (0.47–1.15)
Muslim	64 (30.5)	146 (69.5)	1	1
Frequency of religious attendance
Frequent attendants (At least twice a week)	89 (17.4)	423 (82.6)	0.11 (0.06–0.19)***	0.13 (0.07–0.25)***
Moderate attendants (Once a week)	67 (30.7)	151 (69.3)	0.22 (0.12–0.42) ***	0.30 (0.15–0.60) *
Low attendants (One month or in a year)	36 (66.7)	18 (33.3)	1	1

Ref-reference category

*P-value <0.05

***P-value <0.001, CI-confidence interval

Current drug use

The prevalence of current drug use for recreational purposes was 17.5%, with significant sex, age, and family characteristics variations. In the unadjusted model presented in Table 3, sex, age, living in the same household as one's father, mother alive, living in the same household as one's mother, family structure, family support, religious affiliation and higher frequency of religious attendance were associated with recreational drug use. However, age, living in the same household as one's mother, family support, and frequent religious fellowship attendance remained significantly associated with current drug use for recreational purposes in the adjusted model. Adequate family support was protective against recreational drug use. Individuals who received adequate support from home were 53% less likely to currently use drugs for recreational purposes compared with those who did not. Students who lived in the same household as their mother were 71% less likely to currently use recreational drugs compared with their counterparts who did not. Students who fellowshipped in orthodox churches were 44% less likely to use drugs for recreational purposes compared to those who were Muslims. Also, those who attended religious services every day or at least twice a week were 86% less likely to use drugs for recreational purposes compared with those who attended only once in a month or in a year.

Table 3

Multivariable analysis showing predictors of current drug use among university students.

Variables	Yes n (%)	No n (%)	Unadjusted Odds Ratio (95% CI)	Adjusted Odds Ratio (95% CI)
All	137 (17.5)	647 (82.5)
Sex
Male	84 (20.9)	318 (79.1)	1.64 (1.13–2.39)*	1.39 (0.92–2.12)
Female (Ref)	53 (13.9)	329 (86.1)	1	1
Age
Below 20 years	25 (11.4)	194 (88.6)	0.52 (0.33–0.83)*	0.60 (0.36–1.01)
20 years and above (Ref)	112 (19.8)	453 (80.2)	1	1
Father alive
Yes	109 (16.7)	545 (83.3)	0.73 (0.46–1.16)	0.97 (0.50–1.88)
No (Ref)	28 (21.5)	102 (78.5)	1	1
Live with you
Yes	87 (15.3)	480 (84.7)	0.40 (0.26–0.63)***	0.72 (0.41–1.25)
No (Ref)	38 (31.1)	84 (68.9)	1	1
Mother alive
Yes	114 (16.3)	586 (83.7)	0.53 (0.31–0.90)*	2.42 (1.12–5.21)*
No (Ref)	22 (26.5)	61 (73.5)	1	1
Live in the same household as mother
Yes	89 (13.9)	553 (86.1)	0.22 (0.13–0.37)***	0.29 (0.16–0.52)***
No (Ref)	32 (42.1)	44 (57.9)	1	1
Family type
Nuclear family	69 (21.2)	256 (78.8)	0.63 (0.44–0.92)*	1.12 (0.68–1.83)
Single parent/polygamous/foster parent (Ref)	64 (14.3)	384 (85.7)	1	1
Family support
Adequate/moderate support	26 (42.6)	35 (57.4)	0.24 (0.14–0.42)***	0.39 (0.21–0.73)*
No or insufficient support (Ref)	26 (42.6)	35 (57.4)	1	1
Religious affiliation
Christian-Orthodox	46 (15.1)	258 (84.9)	0.62 (0.39–0.97)*	0.56 (0.34–0.93)*
Christian-Pentecostal	44 (16.3)	226 (83.7)	0.68 (0.43–1.07)	0.76 (0.46–1.25)
Muslim	47 (22.4)	163 (77.6)	1	1
Frequency of religious attendance
At least twice a week	61 (11.9)	451 (88.1)	0.11 (0.06–0.20)**	0.14 (0.07–0.26)***
Once a week	46 (21.1)	172 (78.9)	0.21 (0.11–0.40) ***	0.29 (0.15–0.57)***
Once month or in a year	30 (55.6)	24 (55.6)	1	1

Ref-reference category

*p-value <0.05

***p-value <0.00, CI-confidence interval

Frequency of drug use

The findings on the frequency of drug use are shown in Fig 1. The median number of days participants used drugs over the past month was six days. Of the 137 students who currently use drugs, 23.8% used drugs in more than 10 days of the last month. Males (30.%; n = 25/84) were significantly more likely to have used drugs for more than 10 days of last month before the study compared to females (13.3%; n = 7/53).

Fig 1

Frequency of drug use by gender.

Discussion

Our study is motivated by the paucity of data, especially among university students, on recreational drug use in Nigeria. Given the media attention to the abuse of drugs, such as Tramadol and Codeine, our study is timely and provides vital data for policymakers tasked with addressing illicit drug use in Nigeria. The present study shows that approximately a quarter of the university students in Nigeria have ever used substances/drugs like Codeine, Marijuana, and Tramadol, among others, while close to one-fifth are current users. The only study conducted among university students in Nigeria [26] is outdated and reported a low prevalence of drug use compared to our study. A study has shown that the prevalence of drug use has increased since the 1990s [8]. Also, the abuse of tramadol and codeine, in particular, may have contributed to the increasing prevalence of recreational drug use among young people in Nigeria. Altogether, there is a need to for policymakers to prioritise Nigeria campuses for drug abuse prevention interventions, considering the deleterious effects of drug use on the health of young people.

Based on SEM [20], factors that influence recreational drug use among young people operate at the individual, microsystem, mesosystem, exosystem and macrosystem levels. From our findings, gender was the only individual-level factor significantly associated with recreational drug use. Males were significantly more likely to use drugs compared to females. Similarly, males are frequent drug users relative to females. These results are consistent with previous studies on drug use [27-29]. One plausible reason for this is that boys are more favourable to taking risks compared with girls. Boys generally engage more in unhealthy lifestyles relative to girls [30]. Another plausible reason for the observed gender differences in drug use in this study is cultural expectations. There is more societal stigma and shame around women and girls drug use in the Nigeria context [8]. Also, this finding suggests that males are more exposed to the deleterious consequences of drug use compared to females. However, the prevalence of drug use is relatively high in both genders, which suggests the need to target both males and females with any interventions tailored to address illicit drug use on Nigerian campuses.

Also, based on SEM [20], family/household factors are important predictors of recreational drug use. Our study shows that being from a nuclear family was associated with a lower likelihood of drug use in the unadjusted model; however, the effect size was no longer significant after controlling for demographic factors. Previous studies have reported conflicting findings on the relationship between family structure and drug use among young people [31-34]. Some studies show that family structure is associated with drug use [32-34]; however, there is evidence that family structure had little impact on drug use after controlling for covariates [35]. The plausible reason why the nuclear family had some effect on adolescent and young adults' illicit drug use is that having and living with both parents means more parental monitoring, training and control. When one parent is away, the other parent can take over the caring of the child, unlike in a single-parent family.

We also found that living with one’s father is protective against drug use in the unadjusted regression analysis, but the effect size reduced and was no longer significant after adjusting for important covariates. A study has shown that the presence of a father is protective against drug use, especially for boys [36]. The presence of fathers is important for adolescents and particularly boys. Our study further shows that living with the mother is protective against recreational drug use. The protective effect of the presence of the mother in the life of young person against drug abuse is substantial and remains after controlling for important covariates. Students who lived in the same household as their mother had a lower likelihood of current and ever use of drugs compared with their counterparts who did not. One explanation for this finding is that young adults who did not live with their mothers, either as a result of death or divorce, may experience behavioural challenges. Based on anecdotal knowledge, mothers are essential for exerting control over the behaviours of young adults, especially in Nigeria, where the burden of parenting lies mainly on mothers. An alternative explanation could be those young adults who did not live with their mother either as a result of death or divorce use drugs as a coping mechanism for dealing with the loss of their mothers. Our explanation is bolstered by studies that established that the death of a mother could devastate the health and economic well-being of a family, especially that of the children [37-40]. Children whose mothers died are abandoned by their fathers, undernourished, forced to drop out of school, to take on difficult household and farm tasks and are far less likely to survive [37-40]. Overall, the importance of having both mother and father present in the life of a young person cannot be overemphasised. By and large, the protective effect of mothers against drug use is far more significant compared with fathers. Our finding is supported by a study which demonstrated that drug use among daughters living with single-fathers exceeded that of daughters living with single-mothers [41].

Another key finding of this study is that adequate family support was protective against recreational drug use. Individuals who received adequate support from home were 53% less likely to currently use drugs for recreational purposes compared towith those who did not. This study is consistent with a previous study that argues that parental support and monitoring are important predictors of young people's health outcomes [42]. Our study provides strong evidence for the importance of family support as a protective factor against illicit drug use. A study has established that young people who have strong bonds with their families are less likely to use recreational drug [43]. The importance of family support on young people's illicit drug use is noted in a study that shows that high levels of parental monitoring and family support were effective in buffering the relation between witnessing violence with the initiation of cigarette as well as advanced alcohol use at low levels of witnessing violence [44]. However, a study showed that patterns of drug use among young people coincided with patterns of family conflict, but not family support [45].

We also found strong evidence in support of the protective effect of religion on recreational drug use. Frequent association and fellowship with other people tend to serve as social control against illicit drug use. Religion has a strong influence on the lives of young people. It serves an important agent of socialisation and an institution where young people are taught to behave well and follow religious norms. Religious teachings forbid delinquent behaviours; it teaches young people to follow the laws, which prohibits illicit drug use. Religion acts as a form of social control against illicit drug use, and those that regularly worship tend to abstain from illicit drug use.

The limitation of this study includes the use of cross-sectional design, which does not provide information on causal inference. We conducted this study among a subset of Nigerians young people who are more educated compared to others. As such, our study is not generalizable to all young people in Nigeria. Also, we did not ask questions about specific drugs or the use of multiple drugs. As such, we are unable to estimate the prevalence and correlates of use of specific drugs. Further, we did not examine the role of peer influence and other structural factors on recreational drug use in this study. Despite these limitations, our study advances the discourse of recreational drug use in the Nigerian context and identifies key protective factors against drug use. Future studies should estimate the prevalence of the use of specific drugs like Codeine Syrup, Tramadol, and Cannabis as well as the influence of peers on recreational drug use.

Conclusion

This study estimated the prevalence of and examined the correlates of recreational drug use among Nigerian university students. Our results showed a high prevalence of recreational drug use among students with significant sex variations. Given the study findings and harmful consequences of illicit drug use, there is a need for interventions to address recreational drug use on Nigerian campuses. The SEM provided a framework for understanding the influence of individual-level factors, family/household factors and religion on recreational drug use among adolescent and young adults. Our findings underscore that relevance of SEM in understanding adolescent and young people's behaviours. Even though SEM did not inform the design of this study, it proves relevant in understanding the context in which family factors impact adolescents development. One criticism of SEM is that it is difficult to evaluate all its components empirically. We did not include other important SEM factors, including peer influence and structural factors such as governmental policies and law enforcement in our study. As such, our study did not evaluate the overall applicability of SEM; rather, it drew from SEM to understanding the factors influencing adolescents and young adults’ drug use.

19 Feb 2020

PONE-D-19-31030

Recreational drug use among Nigerian university students: prevalence, determinants and frequency of use

PLOS ONE

Dear Dr Ajayi,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

We would appreciate receiving your revised manuscript by Apr 04 2020 11:59PM. When you are ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter.

To enhance the reproducibility of your results, we recommend that if applicable you deposit your laboratory protocols in protocols.io, where a protocol can be assigned its own identifier (DOI) such that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols

Please include the following items when submitting your revised manuscript:

A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). This letter should be uploaded as separate file and labeled 'Response to Reviewers'.

A marked-up copy of your manuscript that highlights changes made to the original version. This file should be uploaded as separate file and labeled 'Revised Manuscript with Track Changes'.

An unmarked version of your revised paper without tracked changes. This file should be uploaded as separate file and labeled 'Manuscript'.

Please note while forming your response, if your article is accepted, you may have the opportunity to make the peer review history publicly available. The record will include editor decision letters (with reviews) and your responses to reviewer comments. If eligible, we will contact you to opt in or out.

We look forward to receiving your revised manuscript.

Kind regards,

Aparup Das, Ph. D.

Academic Editor

PLOS ONE

Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

http://www.journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and http://www.journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

2. We noticed you have some minor occurrence of overlapping text with the following previous publication(s), which needs to be addressed:

https://doi.org/10.1017/S0021932018000330

In your revision ensure you cite all your sources (including your own works), and quote or rephrase any duplicated text outside the methods section. Additionally, in your Introduction and Discussion please cite and discuss your previous ONE publication and describe the current studies relationship to that manuscript. Ensure you cite any publications using the same dataset. Further consideration is dependent on these concerns being addressed.

3. We note you have included a table to which you do not refer in the text of your manuscript. Please ensure that you refer to Table 3 in your text; if accepted, production will need this reference to link the reader to the Table.

4. Your ethics statement must 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 also ensure that your ethics statement is included in your manuscript, as the ethics section of your online submission will not be published alongside your manuscript.

Additional Editor Comments (if provided):

The manuscript has been reviewed by two independent reviewers and both have found the manuscript to be of merit for potential publication. However, they have indicated several issues which the authors need to address before the manuscript is re-considered. The authors are accordingly advised to revise the manuscript as suggested by the reviewers.  A table consisting of point-wise replies/corrections made in the manuscript (with page and line number) independently for each reviewer should be submitted along with the revised manuscript.

[Note: HTML markup is below. Please do not edit.]

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: Partly

Reviewer #2: Yes

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

Reviewer #1: Yes

Reviewer #2: Yes

**********

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: Yes

Reviewer #2: Yes

**********

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

**********

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: This manuscript is about the recreational drug use and associated factors among Nigerian university students and has the potential to contribute to the literature if revised. The introduction is lengthy and organization could be improved. The stated theory guiding the analysis is only mentioned in the introduction and results are sometimes overstated given the data. Below are suggestions for revision.

Abstract

• The authors stated that they elicit determinants of recreational drug use, but it is a cross-sectional study so authors should be careful with using causal language.

Background

• Authors state abuse of opioids is growing in developed and more recently developing nations, yet the citations for developing nations are older than the citations for developed nations. Thus, it does not appear to be more recent in developing nations.

• It is unclear what the study is about until the very end of the background. Since the first sentence is about opioids, it appeared that that’s what the manuscript is about. Yet almost all of the studies cited do not report these substances, and the study measures codeine, tramadol, and marijuana together.

• The introduction can be better organized. Since SEM is used as the theoretical framework, that should be introduced earlier and the introduction follow that as the outline for drug use among young adults. That should lead to a paragraph before the hypotheses about what this manuscript contributes to the literature that we do not already know, and the purpose of the study.

Method

• Why were codeine, marijuana, and Tramadol combined into 1 question? The authors should explain why they did not assess substances separately.

• How is “ease tension” defined?

• Independent variables: More information is needed on each of the variables. How was age categorized? It is mentioned that family support is monetary and emotional. How was the question phrased to students? Did they understand the emphasis was on emotional support? And what family is included in family support? Was it specified that it was parents? Religious background was not included.

• It is unclear how SEM is applied in the methodology; authors should consider how the variables fit into the theoretical framework.

Discussion

• The authors state their study provides data to help address the opioid crisis, yet marijuana was included in the question so there is no way to know how many students actually used codeine or tramadol. The authors portray throughout the manuscript that this assesses opioid use, yet there is no way to know how many students actually used opioids. As such, the emphasis should be taken off of opioids and state recreational drug use instead.

• Some of the conclusions made are beyond the scope of the study. The authors mention mothers may be the pillar of support but that is unknown since who the support is provided by is not measured (just family). The authors should carefully consider all of their conclusions and ensure they are supported by results.

• The authors should consider other limitations mentioned in previous statements.

• There is no mention of SEM in the discussion and how it is applied to the results.

Reviewer #2: The manuscript fills in critical gap about the exposure of Nigerian university students to recreational drug use, and the finding about the protective role of mother in this scenario is enlightening. Still, few things remain unanswered in the paper like whether these mothers are working/non-working, what is the age range of participants, in which courses the students were enrolled (undergraduate/postgraduate) because that will predict their capacity to handle the enticements for drug use. Similarly, type of polygamy needs to be clarified. According to the manuscript when either parents are not alive then there is greater tendency to use recreational drugs, and this could be explored further more rigorously later. The United Nations Office on Drug Use and Crime came up with "Drug Use in Nigeria, 2018" which has elaborately discussed about use of recreational drug use and needs to be referred to by the authors for future studies. It is suggested to make the language of the manuscript crisper and more palatable and freer from typographical errors.

I wish the authors all the best for their future endeavors.

**********

6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2:

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files to be viewed.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email us at figures@plos.org. Please note that Supporting Information files do not need this step.

19 Mar 2020

Reviewer #1: This manuscript is about the recreational drug use and associated factors among Nigerian university students and has the potential to contribute to the literature if revised. The introduction is lengthy and organization could be improved. The stated theory guiding the analysis is only mentioned in the introduction and results are sometimes overstated given the data. Below are suggestions for revision.

Response

We thank the reviewer for these constructive comments. We have revised the manuscript accordingly. We have discussed the theory in the study discussion

Abstract

• The authors stated that they elicit determinants of recreational drug use, but it is a cross-sectional study so authors should be careful with using causal language.

Response: we have revised the manuscript and ensured all the use of determinants were changed to associated factors.

Background

• Authors state abuse of opioids is growing in developed and more recently developing nations, yet the citations for developing nations are older than the citations for developed nations. Thus, it does not appear to be more recent in developing nations.

Response: We have updated references to show more recent studies for developing countries.

• It is unclear what the study is about until the very end of the background. Since the first sentence is about opioids, it appeared that that’s what the manuscript is about. Yet almost all of the studies cited do not report these substances, and the study measures codeine, tramadol, and marijuana together.

Response: The background which contains review of literature focuses on our measures of illicit drugs and this has been better highlighted.

• The introduction can be better organized. Since SEM is used as the theoretical framework, that should be introduced earlier and the introduction follow that as the outline for drug use among young adults. That should lead to a paragraph before the hypotheses about what this manuscript contributes to the literature that we do not already know, and the purpose of the study.

Response: the introduction has been revamped.

Method

• Why were codeine, marijuana, and Tramadol combined into 1 question? The authors should explain why they did not assess substances separately.

Response: we thank the reviewer for the insights and suggestions. These comments are cogent and have helped us to improve our manuscript. We performed a secondary analysis of dataset that only asked questions about recreational drug use. The question was phrased to probe use of drugs for recreational purposes. The questions gave examples of drugs such as codeine, marijuana and tramadol among others. Again the framing of the question contains examples of drugs people use in the study area for recreational purpose. This is an obvious limitation of this study and we have indicated this in the study limitation.

• How is “ease tension” defined?

Response: We left the interpretation of stress and tension to our respondent because we did not consider it to be an ambiguous term. Also, participants in the pilot study did not find the meaning cumbersome.

Response:

• Independent variables: More information is needed on each of the variables. How was age categorized? It is mentioned that family support is monetary and emotional. How was the question phrased to students? Did they understand the emphasis was on emotional support? And what family is included in family support? Was it specified that it was parents?

Response: These comments are really important and we have provided a detailed description of how all variables were measured.

Religious background was not included.

Response: we have now included religion.

• It is unclear how SEM is applied in the methodology; authors should consider how the variables fit into the theoretical framework.

Response : this is an important comment. We have describe how this model fits our data and acknowledge the limitation of our data.

Discussion

• The authors state their study provides data to help address the opioid crisis, yet marijuana was included in the question so there is no way to know how many students actually used codeine or tramadol. The authors portray throughout the manuscript that this assesses opioid use, yet there is no way to know how many students actually used opioids. As such, the emphasis should be taken off of opioids and state recreational drug use instead.

Response: we have refrain from this kind of generalisation and focus only on recreational drug use which is the main focus of this study. We thank the reviewer for this important comment.

• Some of the conclusions made are beyond the scope of the study. The authors mention mothers may be the pillar of support but that is unknown since who the support is provided by is not measured (just family). The authors should carefully consider all of their conclusions and ensure they are supported by results.

Response: we have deleted this sentence.

• The authors should consider other limitations mentioned in previous statements.

Response: we have elaborated on the limitations of the study.

• There is no mention of SEM in the discussion and how it is applied to the results.

Response: We have discussed the theory in our discussion.

Reviewer #2: The manuscript fills in critical gap about the exposure of Nigerian university students to recreational drug use, and the finding about the protective role of mother in this scenario is enlightening.

Response: we appreciate the reviewer for the positive feedback

Still, few things remain unanswered in the paper like whether these mothers are working/non-working,

Response: we did not measure the employment status or income of the mothers.

What is the age range of participants, in which courses the students were enrolled. (undergraduate/postgraduate) because that will predict their capacity to handle the enticements for drug use.

Response: We have indicated the age range of the students (17-34 years). They are all undergraduate students selected from first year to fifth year of study, including from all faculties of study in the two universities.

Similarly, type of polygamy needs to be clarified. According to the manuscript when either parents are not alive then there is greater tendency to use recreational drugs, and this could be explored further more rigorously later.

Response: we agree with the reviewer that more studies are needed to understand this link.

The United Nations Office on Drug Use and Crime came up with "Drug Use in Nigeria, 2018" which has elaborately discussed about use of recreational drug use and needs to be referred to by the authors for future studies.

Response: we did reference this report in our paper. “Nigeria has been noted to be the current highest consumer of cannabis and amphetamine in Africa (The United Nations Office on Drugs and Crime (UNODC), 2018).”

It is suggested to make the language of the manuscript crisper and more palatable and freer from typographical errors.

Response: we have edited our manuscript and it reads well now.

I wish the authors all the best for their future endeavors.

Response: the reviewer raised important insights that have allowed us to revise and improve our manuscript. We thank the reviewer for the important insights.

8 Apr 2020

PONE-D-19-31030R1

Recreational drug use among Nigerian university students: prevalence, correlates and frequency of use

PLOS ONE

Dear Dr Ajayi,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

I now have the comments of the two reviewers who have reviewed this manuscript in its original form. As you can see from their comments, both have indicated 'minor revision'. I therefor would ask you to revise the manuscript carefully based on individual comments put by both the reviewers for further consideration.

We would appreciate receiving your revised manuscript by May 23 2020 11:59PM. When you are ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter.

To enhance the reproducibility of your results, we recommend that if applicable you deposit your laboratory protocols in protocols.io, where a protocol can be assigned its own identifier (DOI) such that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols

Please include the following items when submitting your revised manuscript:

A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). This letter should be uploaded as separate file and labeled 'Response to Reviewers'.

A marked-up copy of your manuscript that highlights changes made to the original version. This file should be uploaded as separate file and labeled 'Revised Manuscript with Track Changes'.

An unmarked version of your revised paper without tracked changes. This file should be uploaded as separate file and labeled 'Manuscript'.

Please note while forming your response, if your article is accepted, you may have the opportunity to make the peer review history publicly available. The record will include editor decision letters (with reviews) and your responses to reviewer comments. If eligible, we will contact you to opt in or out.

We look forward to receiving your revised manuscript.

Kind regards,

Aparup Das, Ph. D.

Academic Editor

PLOS ONE

Additional Editor Comments (if provided):

Please see my comments above

[Note: HTML markup is below. Please do not edit.]

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: All comments have been addressed

Reviewer #2: (No Response)

**********

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

Reviewer #2: Partly

**********

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

Reviewer #1: Yes

Reviewer #2: Yes

**********

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: Yes

Reviewer #2: Yes

**********

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: No

Reviewer #2: Yes

**********

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: Overall, this manuscript is much improved. There are still some aspects the authors should consider.

Authors should ensure that the manuscript is written in past-tense since they already conducted the study, that all acronyms are defined (i.e., SSA for sub-Saharan Africa), and should consider hiring a copy-editor.

The introduction could be further refined. The authors only need 1 or 2 paragraphs introducing recreational drug use and why it needs to be addressed among this population. Then they should introduce their theory/model and how those variables at each level are related to recreational drug use.

In the introduction, the authors introduce factors in the introduction related to SEM, yet do not evaluate all of those factors in analyses. If the factors remain in the introduction, it should be discussed in the limitations sections why they were not included.

What are the implications of these findings as it relates to SEM? Rather than just listing the results of the different variables, what is the implication of these results (or where does future research need to go) to adequately apply SEM to recreational drug use among university students. The authors may want to consider another model as the focus seems to be on demographic and family/household factors rather than factors from the various SEM levels.

Reviewer #2: The study advances the discourse of recreational drug use in the Nigerian context, especially for the Nigerian youth going to universities and identifies protective factors against drug use in this context. The study has potential for publication and these points must be considered for the same:

Using SEM the study tries to explore various factors correlated with use of recreational drugs. In the abstract though there is no mention of SEM. In this model, however, how authors have defined and differentiated between the social and environmental factors is not clear. Say for e.g. why religion is considered as an environmental factor here – are there any previous studies which take such notions into consideration and/or relate recreational drug use with religion? This is so because it is more of a socio-cultural construct than an environmental one. Then, in table no. 1 religion is given as a demographic factor and later as an environmental one. I feel fitting of the present study into SEM is merely a post-hoc exercise and I have reservations about considering religion as an environmental and not social factor in the present study. The authors should shed more light on this aspect.

In the present study while delineating SEM the authors describe that they have taken into consideration the structure of family and not monitoring of young ones (pg 5). Any particular reason for not considering monitoring as a potential factor.

There are few instances of conflict in the manuscript which need to be resolved while revising like – On page 4 the sentence “We focused ….. recreational purpose.” Appears while later they show association between the mother’s influence on taking the recreational drugs, and here they are of the view that university students are free from parental control and supervision. Similarly, on pg. 5 it says “However, the federal ….. in Nigeria.”, then how come the participants in the present study were getting it for use.

In continuation of the previous point, the authors can consider the place of indulging in recreational drug which has not been delineated. This could be an environmental factor in the study. This is important because had the place been home then family factor comes into play. But if the place is university then already there is no role of family/parents there and the peer group assumes importance.

About study design - Was the study tool i.e. self-designed questionnaire influenced by some already existing questionnaire? I feel it is better to use “gender” instead of “sex” as an Independent variable. There is a typo when dealing with Independent variable – “school fee” should be “university fee”.

Results - in the present study the way in which use of recreational drugs has been explored confounds the fact that whether the users use it for “pleasure” or “to ease tension/stress”. The two things could not and should not be mixed in a single question because then the motivation for using the recreational drug gets diffused and not expressed.

Further, the study does not provide explanations for various findings like – why there is lesser current drug use among the female students than the male ones. Similarly, what is the reason for “our study shows that the nuclear family structure was independently associated with a lower likelihood of drug use in the unadjusted model” (pg. 16).

Discussion section– There are speculative sentences like “it is possible that the prevalence of drug use has increased since the 1990s.” (pg. 15) even though literature and reports like "Drug use in Nigeria, 2018" by United Nations Office on Drug Use and Crime are there. Further, it is felt that it is alright to to relate with presence of mother in the household, but this could be possible in a nuclear family scenario also where mother is also present along with the father and children.

Lastly, it is advised to the authors to not go for overarching ambitious conclusions which are beyond the ambit of present study.

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files to be viewed.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email us at figures@plos.org. Please note that Supporting Information files do not need this step.

24 Apr 2020

Reviewer #1: Overall, this manuscript is much improved. There are still some aspects the authors should consider.

Authors should ensure that the manuscript is written in past-tense since they already conducted the study, that all acronyms are defined (i.e., SSA for sub-Saharan Africa), and should consider hiring a copy-editor.

Response: we defined all acronyms and copy-edited the manuscript.

The introduction could be further refined. The authors only need 1 or 2 paragraphs introducing recreational drug use and why it needs to be addressed among this population. Then they should introduce their theory/model and how those variables at each level are related to recreational drug use.

Response: We have limited the introduction to only three paragraphs and cut down on the theoretical framework given that the theory only helped us to understand the influence of some family factors on recreational drug use.

In the introduction, the authors introduce factors in the introduction related to SEM, yet do not evaluate all of those factors in analyses. If the factors remain in the introduction, it should be discussed in the limitations sections why they were not included.

Response: The theory did not inform the study design, rather we drew on the theory to explain our results regarding the role of the family on recreational drug use among adolescents and young adults. We have indicated this in the study, under the study limitation as well as under suggestions for future studies. We have also removed factors that were not considered in the analysis from the introduction,

What are the implications of these findings as it relates to SEM? Rather than just listing the results of the different variables, what is the implication of these results (or where does future research need to go) to adequately apply SEM to recreational drug use among university students. The authors may want to consider another model as the focus seems to be on demographic and family/household factors rather than factors from the various SEM levels.

Response: We have added a paragraph in the discussion to note the implication of our findings as it related to SEM. Also, we highlighted in this section our use SEM and the limitations thereof.

Response:

Reviewer #2: The study advances the discourse of recreational drug use in the Nigerian context, especially for the Nigerian youth going to universities and identifies protective factors against drug use in this context. The study has potential for publication and these points must be considered for the same:

Response: We thank the reviewer for the positive feedback as well as the constructive criticism of our paper. We have learnt a lot through this process and our paper has improved because of these comments.

Using SEM the study tries to explore various factors correlated with use of recreational drugs. In the abstract though there is no mention of SEM.

Response: we have added a sentence in abstract to introduce SEM.

In this model, however, how authors have defined and differentiated between the social and environmental factors is not clear. Say for e.g. why religion is considered as an environmental factor here – are there any previous studies which take such notions into consideration and/or relate recreational drug use with religion? This is so because it is more of a socio-cultural construct than an environmental one. Then, in table no. 1 religion is given as a demographic factor and later as an environmental one. I feel fitting of the present study into SEM is merely a post-hoc exercise and I have reservations about considering religion as an environmental and not social factor in the present study. The authors should shed more light on this aspect.

Response: We agree with the reviewer that religion is a social factor and not an environmental factor. We have made this change in the study. We have retitled Table 1 as well to reflect this change.

In the present study while delineating SEM the authors describe that they have taken into consideration the structure of family and not monitoring of young ones (pg 5). Any particular reason for not considering monitoring as a potential factor.

Response: We did not collect data on parental monitoring. The structure of the family is an indication of the possible time for monitoring. Young people whose parents had died for instance will have less parental monitoring compared with those whose parents are still alive and living with them.

There are few instances of conflict in the manuscript which need to be resolved while revising like – On page 4 the sentence “We focused ….. recreational purpose.” Appears while later they show association between the mother’s influence on taking the recreational drugs, and here they are of the view that university students are free from parental control and supervision. Similarly, on pg. 5 it says “However, the federal ….. in Nigeria.”, then how come the participants in the present study were getting it for use.

Response: we have deleted these contradictions. The influence of parents on the life of child is lifelong. Even when one’s parent is not there, the need to represent them and not disappoint them continue to influence young people’s behaviours, especially in the context of Nigeria where several parents are responsible for young people most of their life course.

In continuation of the previous point, the authors can consider the place of indulging in recreational drug which has not been delineated. This could be an environmental factor in the study. This is important because had the place been home then family factor comes into play. But if the place is university then already there is no role of family/parents there and the peer group assumes importance.

Response: This is difficult to tell given that we did not ask our participants where they use drugs. We do agree with the reviewer that these would help underscore the environmental factor and who will have more influence. Also, we did not collect data on peer-influence. These are limitations of this study and we have stated this.

About study design - Was the study tool i.e. self-designed questionnaire influenced by some already existing questionnaire? I feel it is better to use “gender” instead of “sex” as an Independent variable.

Response: we have changed sex to gender

There is a typo when dealing with Independent variable – “school fee” should be “university fee”.

Response: we have made this change

Results - in the present study the way in which use of recreational drugs has been explored confounds the fact that whether the users use it for “pleasure” or “to ease tension/stress”. The two things could not and should not be mixed in a single question because then the motivation for using the recreational drug gets diffused and not expressed.

Response: While we agree with the reviewer’s point, we will like to also note that one of the underlying reasons for using drugs for pleasure could be to improve life in some ways. Most people that use drugs says it helps to ease tension. These drugs are also often called recreational drugs. Recreational drugs is a loose term that refers to legal and illegal drugs that are used without medical supervision (https://www.bmj.com/content/353/bmj.i2775/rr). Our inclusion of tension in the question is to have a broad response from our participants given that the drugs themselves are referred to as recreational drugs.

Further, the study does not provide explanations for various findings like – why there is lesser current drug use among the female students than the male ones. Similarly, what is the reason for “our study shows that the nuclear family structure was independently associated with a lower likelihood of drug use in the unadjusted model” (pg. 16).

Response: We have added these points in our discussion. Boys are more favourable to taking risks and society frown at girls drug use.

Discussion section– There are speculative sentences like “it is possible that the prevalence of drug use has increased since the 1990s.” (pg. 15) even though literature and reports like "Drug use in Nigeria, 2018" by United Nations Office on Drug Use and Crime are there.

Response: we have added references to these kinds of statements.

Further, it is felt that it is alright to relate with presence of mother in the household, but this could be possible in a nuclear family scenario also where mother is also present along with the father and children.

Response: We have explained our position on this based on the fact that emotional nurturance may be higher among mothers regardless of the family structure. It is also possible that mothers may have more appropriate consequences for youth behaviours which may eventually protect them.

Lastly, it is advised to the authors to not go for overarching ambitious conclusions which are beyond the ambit of present study.

Response: we do agree with the reviewer and have noted this point in the discussion. We have revised the conclusion to underscore the reviewer’s point.

27 Apr 2020

Recreational drug use among Nigerian university students: prevalence, correlates and frequency of use

PONE-D-19-31030R2

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29 Apr 2020

PONE-D-19-31030R2

Recreational drug use among Nigerian university students: prevalence, correlates and frequency of use

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