Peer influence in adolescent drinking behaviour: a protocol for systematic review and meta-analysis of stochastic actor-based modeling studies

INTRODUCTION

Alcohol consumption is a considerable public health problem that is especially harmful to young people. To develop effective prevention programmes targeted at adolescents, it is important to understand the social mechanisms triggering alcohol consumption. Among such mechanisms, peer influence plays an important role. The effects of peer influence are very difficult to evaluate because of the entanglement with social selection, that is, a tendency of people to befriend others with similar behaviour. The recently developed stochastic actor-oriented models (SAOM) approach is designed to disentangle social influence from social selection. The aim of this study is to conduct a systematic review and meta-analysis of studies employing SAOM methodology to evaluate the effects of social influence on adolescent drinking behaviour.

METHODS AND ANALYSIS

In order to analyse the co-evolution of alcohol consumption and adolescent friendship networks, we will collect articles that use SAOM methodology through systematic electronic searches in Web of Science, Scopus, PubMed, The Cochrane Library (Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials), EBSCOhost (MEDLINE, SocINDEX, Academic Source, ERIC), ProQuest (ProQuest Dissertations and Theses Global), PsycINFO (PsycNET), Excerpta Medica database (Embase) and Cumulative Index to Nursing and Allied Health Literature (CINAHL). We will collect the literature from academic journals, dissertations/theses, reports and conference materials. Three reviewers will retrieve and independently assess potentially relevant material in terms of whether they comply with prespecified criteria. Subsequently, we will summarise the results of the studies in a systematic review. If a sufficient number of studies can be found, SAOM quantitative results will be extracted and meta-analysed. The project will go from 1 December 2018 to 1 December 2019.

ETHICS AND DISSEMINATION

Ethical approval will not be required as our work is based on published studies. A list of all the studies included in this work will be available for review. We plan dissemination in a peer-reviewed international scientific journal and through conference presentations. Our review will highlight the peer effect of peers in adolescent drinking behaviour and provide guidance for developing effective prevention and intervention programmes. We expect it to be informative for policy and practice, decision-making as well as for further research in public health and sociology of adolescents.

PROSPERO REGISTRATION NUMBER

CRD42019119836.

Socioeconomic Differences and the Potential Role of Tribes in Young People's Food and Drink Purchasing Outside School at Lunchtime

Socioeconomic deprivation has been linked to food consumption practices, but studies investigating the food environment around schools provide mixed findings. Peer influence and marketing cues are considered important influencers of young people's behaviors. This study used a tribal theory lens to investigate the factors affecting pupils' purchasing and consumption of food/drinks outside schools at lunchtime. A survey was conducted with 243 pupils from seven UK secondary schools of differing socioeconomic status (SES). A purchasing recall questionnaire (PRQ) was developed and administered online at the participating schools to capture food and drink purchasing, intake, and expenditure. No significant differences were found in terms of energy and nutrients consumed or food/drink expenditure between pupils from schools of lower and higher SES. Enjoyment of food shopping with friends was linked with higher food energy intake and spend. Higher susceptibility to peer influence was associated with greater influence from food advertising and endorsements. Without ignoring the impact that SES can have on young people's food choices, we suggest that tribal theory can be additionally used to understand pupils' eating behaviors and we present implications for social marketers and policy makers.

Suggestibility is associated with alcohol self-administration, subjective alcohol effects, and self-reported drinking behavior

BACKGROUND

Suggestibility, defined as an individual's inclination to accept and internalize messages, has not been studied in relation to alcohol use. Peer conformity, a component of suggestibility, may be related to alcohol use, as peer groups show similarities in patterns of alcohol use. Few studies have assessed how suggestibility and peer conformity relate to alcohol self-administration or to reinforcing effects of alcohol.

AIMS

This study assessed whether suggestibility and peer conformity were associated with drinking behavior, alcohol self-administration, subjective response to alcohol, and drinking motives and expectancies.

METHODS

Study 1 participants were alcohol drinkers (n=20), who completed a laboratory study of free-access intravenous alcohol self-administration. Study 2 participants were adolescents and young adults, age 14-25 (n=150), with lifetime alcohol use. Participants completed surveys of suggestibility and drinking patterns (Study 1 and 2), subjective alcohol effects (Study 1 only), and alcohol motives and expectancies (Study 2 only).

RESULTS/OUTCOMES

In Study 1, participants with higher levels of suggestiblity self-administered more alcohol, and reported greater subjective alcohol effects. Peer conformity, though correlated with suggestibility, was not related to these measures. In Study 2, participants with higher suggestiblity reported more alcohol consumption, higher drinking motives and alcohol expectancies. Peer conformity was not related to alcohol consumption, but was related to coping and enhancement drinking motives, and all expectancies measures.

CONCLUSIONS/INTERPRETATION

Results indicate that suggestibility, beyond peer conformity, may be a critical factor to study when examining alcohol consumption behavior, and may provide insight into the development of alcohol use disorder.

Tobacco Use Behaviors, Attitudes, and Demographic Characteristics of Tobacco Opinion Leaders and Their Followers: Twitter Analysis

BACKGROUND

Tobacco-related content on social media is generated and propagated by opinion leaders on the Web who disseminate messages to others in their network, including followers, who then continue to spread the information. Opinion leaders can exert powerful influences on their followers' knowledge, attitudes, and behaviors; yet, little is known about the demographic characteristics and tobacco use behavior of tobacco opinion leaders on the Web and their followers, compared with general Twitter users.

OBJECTIVE

In this study, we hypothesized that opinion leaders use more tobacco products and have higher nicotine dependence than the other 2 groups (eg, followers and general Twitter users) and that followers-those who spread messages by opinion leaders-would more likely be in demographic groups that are vulnerable to tobacco marketing influence (eg, young adults and lower educational attainment).

METHODS

We constructed the social networks of people who tweet about tobacco and categorized them using a combination of social network and Twitter metrics. To understand the characteristics of tobacco opinion leaders and their followers, we conducted a survey of tobacco opinion leaders, their followers, and general Twitter users. The sample included 347 opinion leaders, 567 followers, and 519 general users. The opinion leaders had a median of 1000 followers, whereas followers and general users had fewer than 600 followers.

RESULTS

Opinion leaders were more likely than their followers to report past month use of tobacco products; followers, in turn, were more likely to report past month use of these products than general Twitter users. The followers appeared to be an especially vulnerable group; they tended to be younger (mean age 22.4 years) and have lower education compared with the opinion leaders and general users.

CONCLUSIONS

Followers of Twitter tobacco opinion leaders are a vulnerable group that might benefit from antitobacco education to counter the protobacco communications they see on social media.

The Association between Substance Abuse and Sexual Misconduct among Macau Youths

This study investigates how peer influence, school attachment, and substance abuse are related to sexual behavior, with particular interest in exploring the relationship between substance abuse and sexual misconduct, while using a stratified random sample of adolescents in Macau. Mediation analyses were employed. The results show that substance abuse, apart from susceptibility to peer influence and school attachment/commitment, was significantly related to sexual misconduct. Substance abuse was the best predictor of sexual misconduct, and it significantly mediated the relationship between susceptibility to peer influence, as well as school attachment and sexual misconduct. This reflects that the use of substances, including drugs, alcohol, and cigarettes, can be viewed as a catalyst for triggering engagement in sexual misconduct. The implications of this study involve taking measures to reduce the rate of substance abuse as a way of decreasing sexual misconduct in adolescents. Future research directions in exploring the relationship between adolescent substance abuse and risky sexual behavior are discussed.

Selection and Socialization Influences on Adolescent Alcohol Use: The Individual and Joint Contexts of Neighborhood Disadvantage and Population Density

Background: Neighborhood disadvantage (ND) and population density (PD) are two community characteristics contextualizing friends' influence on adolescent alcohol use. However, these community characteristics are rarely examined for potential joint contributions, although it is possible that the way friends are selected or influence alcohol use are shaped by both ND and PD. In addition, prior studies examining ND or PD contexts on friend influence rarely discern between socialization and selection. Objectives: The current study examined how selection and socialization influences on adolescent alcohol use are shaped by unique and joint contexts of ND and PD. Methods: Adolescents from Waves I and II of the National Longitudinal Study of Adolescent and Adult Health (Add Health) were included in three models assessing friends' socialization of alcohol us initiation and binge drinking, and selection of drinking friends. ND and PD were tested for mediation and moderation individually and jointly. Results: Results indicated that socialization of drinking initiation was stronger in high ND contexts, and that continued binge drinking was stronger in low ND contexts. PD indirectly influenced socialization of initiation and binge drinking maintenance via a negative association with number of drinking friends. PD and ND jointly influenced the association between initial binge drinking and next-year selection of drinking friends, such that selection was stronger within areas related to lower levels of drinking friends. Conclusions/Importance: Current results indicate that PD and ND shape friends' influence on alcohol use in unique ways. These must be accounted for to better understand bidirectional effects of friend influence.

Exploring the relationship between polygenic risk for cannabis use, peer cannabis use and the longitudinal course of cannabis involvement

BACKGROUND AND AIMS

Few studies have explored how polygenic propensity to cannabis use unfolds across development, and no studies have yet examined this question in the context of environmental contributions such as peer cannabis use. Outlining the factors that contribute to progression from cannabis initiation to problem use over time may ultimately provide insights into mechanisms for targeted interventions. We sought to examine the relationships between polygenic liability for cannabis use, cannabis use trajectories from ages 12-30 years and perceived peer cannabis use at ages 12-17 years.

DESIGN

Mixed-effect logistic and linear regressions were used to examine associations between polygenic risk scores, cannabis use trajectory membership and perceived peer cannabis use.

SETTING

United States.

PARTICIPANTS

From the Collaborative Study on the Genetics of Alcoholism (COGA) study, a cohort of 1167 individuals aged 12-26 years at their baseline (i.e. first) interview.

MEASUREMENTS

Key measurements included life-time cannabis use (yes/no), frequency of past 12-month cannabis use, maximum life-time frequency of cannabis use, cannabis use disorder (using DSM-5 criteria) and perceived peer cannabis use. Polygenic risk scores (PRS) were created using summary statistics from a large (n = 162 082) genome-wide association study (GWAS) of cannabis use.

FINDINGS

Three trajectories reflecting no/low (n = 844), moderate (n = 137) and high (n = 186) use were identified. PRS were significantly associated with trajectory membership [P = 0.002-0.006, maximum conditional R2  = 1.4%, odds ratios (ORs) = 1.40-1.49]. Individuals who reported that most/all of their best friends used cannabis had significantly higher PRS than those who reported that none of their friends were users [OR = 1.35, 95% confidence interval (CI) = 1.04, 1.75, P = 0.023]. Perceived peer use itself explained up to 11.3% of the variance in trajectory class membership (OR = 1.50-4.65). When peer cannabis use and the cannabis use PRS were entered into the model simultaneously, both the PRS and peer use continued to be significantly associated with class membership (P < 0.01).

CONCLUSIONS

Genetic propensity to cannabis use derived from heterogeneous samples appears to correlate with longitudinal increases in cannabis use frequency in young adults.

Effectiveness of peer pressure on computed tomography use for dizziness/vertigo patients

Dizziness/vertigo is a common complaint in the emergency department (ED). We aimed to evaluate the effect of peer pressure on decision making in emergency physicians (EPs) to use computed tomography (CT) for patients with dizziness/vertigo.We conducted a before-and-after retrospective case review of patients who visited the ED with dizziness/vertigo. EPs were categorized into 3 groups according to seniority (in years of experience: >12, 7-12, and <7). The rate of CT use for EPs, patient number, and CT use were e-mailed monthly to update the EP team on the benchmark rate and shape of the behavior.Among the 1657 (preintervention) and 1508 (postintervention) patients with dizziness/vertigo, 320 (19.3%) and 230 (15.3%), respectively, underwent brain CT. A decrease in the rate of CT use was observed in the postintervention group (odds ratio [OR] = 0.743, 95% confidence interval [CI] = 0.615-0.897), especially in junior EPs (years of experience, <7; OR = 0.667, 95% CI: 0.474-0.933) and younger patients (age, <60) (OR = 0.625, 95% CI: 0.453-0.857).The intervention strategy created peer pressure through e-mail reminders and decreased the rate of CT use for patients with isolated dizziness/vertigo, especially in junior EPs and younger patients.

Disentangling longitudinal relations between youth cannabis use, peer cannabis use, and conduct problems: developmental cascading links to cannabis use disorder

AIMS

To determine whether cannabis use during adolescence can increase risk not only for cannabis use disorder (CUD) but also for conduct problems, potentially mediated by exposure to peers who use cannabis.

DESIGN, SETTING, PARTICIPANTS

Longitudinal study analyzing four waves of longitudinal data from 364 racially and socio-economically diverse, urban, US community youth (at baseline: Mage  = 13.51 (0.95); 49.1% female).

MEASUREMENTS

Self-reports of cannabis use, conduct problems, proportion of peers using cannabis and CUD criteria at the final wave were analyzed using a method sensitive to changes over development, the random-intercept cross-lagged panel model.

FINDINGS

Change in cannabis use did not predict changes in conduct problems or peer cannabis use over time, controlling for gender, race-ethnicity and socio-economic status. Instead, increases in conduct problems predicted increases in cannabis use and ultimately CUD, with some of the effect mediated by increases in the prevalence of peer cannabis use [β = 0.12, 95% confidence interval (CI) = 0.07, 0.20]. Additionally, affiliation with peers who used cannabis predicted subsequent CUD via increased personal cannabis use (β = 0.08, 95% CI = 0.04, 0.14). Significant within-person betas for the cross-lagged effects ranged between 0.20 and 0.27.

CONCLUSIONS

Cannabis use in adolescence does not appear to lead to greater conduct problems or association with cannabis-using peers apart from pre-existing conduct problems. Instead, adolescents who (1) increasingly affiliate with cannabis-using peers or (2) have increasing levels of conduct problems are more likely to use cannabis, and this cascading chain of events appears to predict cannabis use disorder in emerging adulthood.

Leading by Example: Web-Based Sexual Health Influencers Among Men Who Have Sex With Men Have Higher HIV and Syphilis Testing Rates in China

Background

The spread of healthy behaviors through social networks may be accelerated by influential individuals. Previous studies have used lay health influencers to prevent sexually transmitted infections (STIs) among internet-using men who have sex with men (MSM). However, there is a lack of understanding of the characteristics of this key subset of MSM.

Objective

This study aimed to examine sociodemographic characteristics, HIV and syphilis testing, and sexual behaviors of Web-based MSM sexual health influencers (SHIs) in China, defined as individuals with relatively stronger influence on spreading HIV and STI information online.

Methods

A Web-based survey of MSM was conducted in August 2017 as a final follow-up of a randomized controlled trial promoting HIV testing in 8 Chinese cities. Men were recruited through a gay social networking mobile phone app and were included if they were born biologically male, aged 16 years and above, ever had sex with another man, and HIV negative or with unknown HIV status. Information regarding sociodemographic characteristics, sexual behaviors, and HIV and syphilis testing was obtained. We assessed men’s Web-based sexual health influence using a standardized 6-item opinion leadership scale focused on HIV and STI information. Influencers were defined as those whose mean score ranked within the top 13% (a higher score means greater influence). We used multivariable linear and logistic regression models to measure Web-based sexual health influence’s association with HIV and syphilis testing, controlling for intervention trial effects, age, education, income, and marital status.

Results

Overall, 1031 men completed the survey. Most men were younger than 30 years (819/1031, 79.43%) and had at least college education (667/1031, 64.69%). Influencers were more likely to get tested for HIV (73/132, 55.3% vs 337/899, 37.5%; P<.001) and syphilis (35/132, 26.5% vs 137/899, 15.2%; P=.001) in the last 3 months compared with noninfluencers. There were no significant differences in condomless sex with male partners (26/132, 19.7% vs 203/899, 22.6%; P=.46), mean number of male sex partners (1.32 vs 1.11; P=.16) in the last 3 months, and mainly meeting male sex partners online in the last 12 months (97/132, 73.5% vs 669/899, 74.4%; P=.82) between influencers and noninfluencers. Regression analyses showed that influencers had higher odds of HIV testing (adjusted odds ratio, AOR 2.16, 95% CI 1.48-3.17) and syphilis testing (AOR 1.99, 95% CI 1.28-3.10) in the last 3 months.

Conclusions

We identified Web-based SHIs who might be more likely to help promote healthy HIV and syphilis testing behaviors through MSM populations. Leveraging existing influencers may help improve HIV and syphilis testing among their networks.

Incarceration history, social network composition, and substance use among homeless youth in Los Angeles

Background: Homeless youth in the United States have high rates of substance use. Existing research has identified social network composition and street-associated stressors as contributing factors. Incarceration is a highly prevalent stressor for homeless youth. Its effect on youth's social network composition and substance use, however, has been neglected. Aims: This study investigated the direct and indirect associations between incarceration history and substance use (through social networks) among homeless youth in Los Angeles, California. Methods: A sample of 1047 homeless youths were recruited between 2011 and 2013. Computerized self-administrated surveys and social network interviews were conducted to collect youth's sociodemographic characteristics, incarceration history, social network composition, and substance use. Bootstrapping was used to identify the direct and indirect associations between youth's incarceration history and substance use. Results: Incarceration history was positively associated with youth's cannabis, methamphetamine, and injection drug use. The percentage of cannabis-using peers partially mediated the associations between incarceration history and youth's cannabis, cocaine, and heroin use. The percentage of methamphetamine-using peers partially mediated the associations between incarceration history and youth's methamphetamine, cocaine, and injection drug use. The percentage of heroin-using peers partially mediated the association between incarceration history and youth's heroin use. Moreover, the percentage of peers who inject drugs partially mediated the associations between incarceration history and youth's methamphetamine, heroin, and injection drug use. Discussion: Incarceration history should be taken to a more central place in future research and practice with homeless youth in the United States.

Risk-taking, peer-influence and child maltreatment: a neurocognitive investigation

Maltreatment is associated with increased risk of a range of psychiatric disorders, many of which are characterized by altered risk-taking propensity. Currently, little is known about the neural correlates of risk-taking in children exposed to maltreatment, nor whether their risk-taking is atypically modulated by peer influence. Seventy-five 10- to 14-year-old children [maltreated (MT) group: N = 41; non-maltreated Group (NMT): N = 34] performed a Balloon Analogue Risk Task (BART), under three different peer influence conditions: while alone, while being observed by a peer and while being encouraged by a peer to take risks. The MT group engaged in less risk-taking irrespective of peer influence. There was no differential effect of peer influence on risk-taking behaviour across groups. At the neural level, the right anterior insula (rAI) exhibited altered risk sensitivity across conditions in the MT group. Across groups and conditions, rAI risk sensitivity was negatively associated with risk-taking and within the MT group greater rAI risk sensitivity was related to more anxiety symptoms. These findings suggest that children with a history of maltreatment show reduced risk-taking but typical responses to peer influence. Abnormal rAI functioning contributes to the pattern of reduced risk-taking and may predispose children exposed to maltreatment to develop future psychopathology.

Peer influence in bullying: The autonomy-enhancing effect of moral competence

Research has found that moral competence is negatively associated with bullying behavior in schools, but the drivers of this association are not yet well understood. In this paper, we report on two studies which suggest that moral competence acts as a moderator of peer influence in the context of school bullying. Data were collected at two time points in three German higher secondary schools (grades 7-10, average age at measurement: 14.26 years). Using a cross-lagged panel design (CLPD), study 1 (N = 251) found adolescents with low moral competence to be susceptible to peer influence, while no such effect was found for adolescents with high moral competence. Study 2, a cross-sectional analysis (N = 748), found moral competence to be inversely related to the likelihood of an individual's conforming with the pro-bullying behavior of his or her peers. Neither study found corresponding effects for pro-social, defending behavior. Our findings further illuminate the associations between moral competence, peer influence, and school bullying. Some implications for bullying prevention are discussed.

Prospective Associations of Actual and Perceived Descriptive Norms with Drinking Among Emerging Adults

BACKGROUND

Descriptive norms are commonly associated with participant drinking. However, study participants may incorrectly perceive that their peers drink about the same amount as they do, which would bias estimates of drinking homogeneity.

OBJECTIVES

This research examined the magnitude of associations between emerging adults' reports of their own drinking and peer drinking measured the previous year by measures of (1) participants' perceptions of friends' drinking; and (2) actual drinking reported by nominated peers.

METHODS

The data are from annual surveys conducted in 2014 and 2015, Waves 4 and 5 (the first 2 years after high school) of 7 annual assessments as part of the NEXT Generation Health Study (n = 323). Associations of participant alcohol use with perceived friend use (five closest, closest male, and closest female friends), and with actual peer use. Logistic regression analyses estimated the magnitudes of prospective associations between each measure of peer drinking at W4 and participant drinking at W5.

Imitating the Risky Decision-Making of Peers: An Experimental Study Among Emerging Adults

This experiment examined whether emerging adults imitate the risky decision-making of peers and whether peer susceptibility functions as a moderator. Overall, 63 emerging adults participated with a confederate of the same gender. The participants were randomly assigned to the experimental (confederate engaged in risky decision-making) or control (confederate did not engage in risky decision-making) condition. Risky decision-making was measured with the Stop-Light Game task, and peer susceptibility was measured with a questionnaire. Linear regression analyses showed that the participants engaged in more risky decision-making when the peer displayed risky decision-making. Peer susceptibility was not found to be a significant moderator of this relationship. The findings showed that health education programs need to consider imitation to reduce the risky decision-making of emerging adults more effectively.

Male Peer Support to Hostile Sexist Attitudes Influences Rape Proclivity

Sexual assault affects a large proportion of women in the world. Although most rapes are committed by one man, the act itself may be influenced by many (e.g., the peer group). Hostile sexism (HS) has repeatedly been associated with men's rape proclivity, but the influence exerted by the HS of the peer group on rape proclivity has not been investigated. In this study, we explored the impact of perceived male peer support to HS on participants' rape proclivity. A sample of Spanish undergraduate students from a university in the south of Spain ( N = 134) completed the Ambivalent Sexism Inventory. Immediately afterwards, they received feedback on the supposed sexist responses of a peer group (high vs. low in HS); we kept the benevolent sexism (BS) of the peer group at medium levels. Next, we assessed participants' rape proclivity using acquaintance rape scenarios. Results showed an interaction between participants' own levels of HS and information about the HS of the peer group. Men high in HS reported higher rape proclivity in the high-HS peer-group condition than in the low-HS peer-group condition. By contrast, information on the peer group did not affect self-reported rape proclivity of men low in HS. Results also corroborated the relationship between participants' levels of HS and rape proclivity, and expanded the literature by revealing an unexpected influence of participants' BS on rape proclivity.

An Examination of Parental and Peer Influence on Substance Use and Criminal Offending During the Transition from Adolescence to Adulthood

Although peer behavior and parent-child-conflict have been associated with adolescent and young adults' behavior, prior studies have not adequately controlled for selection effects and other confounders, or examined whether associations change across the transition to adulthood or by race. Using annual data from young men followed from 17-26, within-individual change models examined whether substance use or offending increased in the year after boys began affiliating with friends who engaged in substance use/offending and/or experienced increased parent-son-conflict. Moderation analyses tested whether associations varied by age or race. Alcohol use, marijuana use, and offending (Black participants only) increased in the year after boys began affiliating with more peers who engaged in similar behaviors. Associations were strongest during adolescence for substance use. Parent-son conflict was not associated with the outcomes. Findings underscore the importance of developmental and racialized differences in understanding the role of social influences on young men's substance use and offending.

Early adolescents' relationships with parents, teachers, and peers and increases in social anxiety symptoms

Previous research on social anxiety has clearly identified interpersonal relationships as important for social anxiety symptoms. Few studies, however, have utilized longitudinal designs and have examined mechanisms that might explain links between negative interpersonal relationships and changes in youths' social anxiety over time. Recent models of social anxiety suggest that negative interpersonal relationships are linked to social anxiety through effects on social skills and behaviors. Using an autoregressive design and a sample of 416 two-parent families (51% female, 91% White), this study examined whether connections among parent-adolescent hostility, teacher support (6th grade), and changes in early adolescent social anxiety symptoms (6th to 8th grades) are mediated by youths' compliance with peers (7th grade). Results indicated that youths who experienced greater parent-adolescent hostility and lower teacher support engaged in greater compliance with peers. In turn, those who engaged in greater compliance with peers experienced increases in social anxiety symptoms. Significant indirect effects were substantiated for only parent-adolescent hostility. Associations were unique to adolescent social anxiety after accounting for depressive symptoms. Associations did not differ for early adolescent girls and boys. The results reveal that nuanced social processes involving social behaviors and relationships with parents and teachers have important and potentially unique implications for changes in early adolescent social anxiety symptoms. (PsycINFO Database Record

Non-medical use of prescription drugs by young men: impact of potentially traumatic events and of social-environmental stressors

Background: Non-medical use of prescription drugs (NMUPD) is an increasing phenomenon associated with physical and psychological consequences. This study investigated the effects of distinct forms of stress on NMUPD. Methods: Data from 5308 young adult men from the Swiss cohort study on substance use risk factors (C-SURF) were analysed regarding NMUPD of sleeping pills, tranquilizers, opioid analgesics, psychostimulants, and antidepressants. Various forms of stress (discrete, potentially traumatic events, recent and long-lasting social-environmental stressors) during the period preceding the NMUPD assessment were measured. Backward log-binomial regression was performed and risk ratios (RR) were calculated. Results: NMUPD was significantly associated with the cumulative number of potentially traumatic events (e.g. for opioid analgesics, RR = 1.92, p < .001), with problems within the family (e.g. for sleeping pills, RR = 2.45, p < .001), and the peer group (e.g. for tranquilizer use, RR = 2.34, p < .01). Factors describing family functioning in childhood showed very few significant associations. Sexual assault by acquaintances was associated only with use of sleeping pills (RR = 2.91, p p <.01); physical assault by acquaintances was not associated with NMUPD. Physical (e.g. for psychostimulants, RR = 2.01, p < .001) or sexual assaults (e.g. for antidepressants, RR = 4.64, p < .001) perpetrated outside the family context did show associations with several drug categories. Conclusion: NMUPD appears to be more consistently associated with discrete and potentially traumatic events and with recent social-environmental stressors than with long-lasting stressors due to family functioning during childhood and youth. Physical and sexual assaults perpetrated by strangers showed more associations with NMUPD than those perpetrated by a family member.

Associations between friendship characteristics and HIV and HSV-2 status amongst young South African women in HPTN-068

INTRODUCTION

Prevalence of HIV among young women in South Africa remains extremely high. Adolescent peer groups have been found to be an important influence on a range of health behaviours. The characteristics of young women's friendships might influence their sexual health and HIV risk via connections to sexual partners, norms around sexual initiation and condom use, or provision of social support. We investigated associations between young women's friendships and their Herpes Simplex Virus Type 2 (HSV-2) and HIV infection status in rural South Africa.

METHODS

Our study is a cross-sectional, egocentric network analysis. In 2011 to 2012, we tested 13- to 20-year-old young women for HIV and HSV-2, and collected descriptions of five friendships for each. We generated summary measures describing friend socio-demographic characteristics and the number of friends perceived to have had sex. We used logistic regression to analyse associations between friend characteristics and participant HIV and HSV-2 infection, excluding likely perinatal HIV infections.

RESULTS

There were 2326 participants included in the study sample, among whom HIV and HSV-2 prevalence were 3.3% and 4.6% respectively. Adjusted for participant and friend socio-demographic characteristics, each additional friend at least one year older than the participant was associated with raised odds of HIV (odds ratio (OR) = 1.37, 95% CI 1.03 to 1.82) and HSV-2 (adjusted OR=1.41, 95% CI 1.18 to 1.69). Each additional friend perceived to have ever had sex also raised the odds of HIV (OR = 1.29, 95% CI 1.03 to 1.63) and HSV-2 (OR=1.18, 95% CI 1.03 to 1.35).

DISCUSSION

We found good evidence that a greater number of older friends and friends perceived to have had sex were associated with increased risk for HSV-2 and HIV infection among young women.

CONCLUSIONS

The characteristics of young women's friendships could contribute to their risk of HIV infection. The extent to which policies or programmes influence age-mixing and young women's normative environments should be considered.

The influence of peer behavior as a function of social and cultural closeness: A meta-analysis of normative influence on adolescent smoking initiation and continuation

Although the influence of peers on adolescent smoking should vary depending on social dynamics, there is a lack of understanding of which elements are most crucial and how this dynamic unfolds for smoking initiation and continuation across areas of the world. The present meta-analysis included 75 studies yielding 237 effect sizes that examined associations between peers' smoking and adolescents' smoking initiation and continuation with longitudinal designs across 16 countries. Mixed-effects models with robust variance estimates were used to calculate weighted-mean Odds ratios. This work showed that having peers who smoke is associated with about twice the odds of adolescents beginning (OR ¯ = 1.96, 95% confidence interval [CI] [1.76, 2.19]) and continuing to smoke (OR ¯ = 1.78, 95% CI [1.55, 2.05]). Moderator analyses revealed that (a) smoking initiation was more positively correlated with peers' smoking when the interpersonal closeness between adolescents and their peers was higher (vs. lower); and (b) both smoking initiation and continuation were more positively correlated with peers' smoking when samples were from collectivistic (vs. individualistic) cultures. Thus, both individual as well as population level dynamics play a critical role in the strength of peer influence. Accounting for cultural variables may be especially important given effects on both initiation and continuation. Implications for theory, research, and antismoking intervention strategies are discussed. (PsycINFO Database Record

Neural Correlates of Social Influence on Risk Taking and Substance Use in Adolescents

Purpose of Review

Adolescents often engage in elevated levels of risk taking that gives rise to substance use. Family and peers constitute the primary contextual risk factors for adolescent substance use. This report reviews how families and peers influence adolescent neurocognitive development to inform their risk taking and subsequent substance use.

Recent Findings

Developmental neuroscience using functional magnetic resonance imaging (fMRI) has identified regions of the brain involved in social cognition, cognitive control, and reward processing that are integrally linked to social influence on adolescent risk taking. These neural mechanisms play a role in how peer and family influence (e.g., physical presence, relationship quality, rejection) translates into adolescent substance use.

Summary

Peers and families can independently, and in tandem, contribute to adolescent substance use, for better or for worse. We propose that future work utilize fMRI to investigate the neural mechanisms involved in different aspects of peer and family influence, and how these contexts uniquely and interactively influence adolescent substance use initiation and escalation across development.

Sickness absence among peer-supported drivers after occupational trauma

Background

Psychological first aid is a common approach for providing support after potentially traumatic events (PTEs). In Germany, a peer support model is recommended by the German Statutory Accident Insurance (DGUV) to reduce sickness absence after occupational accidents, especially in public transportation. However, data on the effectiveness of peer support are very sparse.

Aims

To analyse whether peer support has an impact on sickness absence after work-related traumatic events in public transportation.

Methods

An analysis was conducted in two German public transportation corporations. Due to ethical requirements, we used a historical cohort study comparing peer support by colleagues (VAG-1), peer support at supervisor level (VGF) and a non-intervention group (VAG-0). The study period was from March 2003 to December 2012. We used a negative binominal regression model to estimate the relative risk associated with the interventions and potential confounders.

Results

A total of 259 incident PTEs in employees were observed. A regression analysis identified the severity of PTE (severe and fatal events), VGF and age as significant factors in predicting duration of post-event sickness absence. In a stratified analysis, the mode of peer support (VGF) and age predicted sickness absence for less severe PTEs but this was not significant for severe PTEs.

Conclusions

Severe and fatal PTEs had the strongest impact on sickness absence after PTEs. For less severe PTE, peer support provided by colleagues may be superior to supervisor support.

Young People, Adult Worries: Randomized Controlled Trial and Feasibility Study of the Internet-Based Self-Support Method "Feel the ViBe" for Adolescents and Young Adults Exposed to Family Violence

BACKGROUND

Adolescents and young adults (AYAs) are of special interest in a group of children exposed to family violence (FV). Past-year prevalence of exposure to FV is known to be highest in AYAs and has severe consequences. Peer support is an effective approach to behavior change and the Internet is considered suitable as a mode of delivery.

OBJECTIVE

The study aimed to evaluate both effectiveness and feasibility of a randomized controlled trial (RCT) and feasibility study of the Internet-based self-support method "Feel the ViBe" (FtV) using mixed-methods approach to fully understand the strengths and weaknesses of a new intervention.

METHODS

AYAs aged 12-25 years and exposed to FV were randomized in an intervention group (access to FtV + usual care) and a control group (minimally enhanced usual care) after they self-registered themselves. From June 2012 to July 2014, participants completed the Impact of Event Scale (IES) and Depression (DEP) and Anxiety (ANX) subscales of the Symptom CheckList-90-R (SCL-90) every 6 weeks. The Web Evaluation Questionnaire was completed after 12 weeks. Quantitative usage data were collected using Google analytics and content management system (CMS) logs and data files. A univariate analysis of variance (UNIANOVA) and mixed model analysis (intention-to-treat [ITT], complete case) were used to compare groups. Pre-post t tests were used to find within-group effects. Feasibility measures structurally address the findings. The CONsolidated Standards Of Reporting Trials of Electronic and Mobile HEalth Applications and onLine TeleHealth (CONSORT-EHEALTH) checklist was closely followed.

RESULTS

In total, 31 out of 46 participants in the intervention group and 26 out of 47 participants in the control group started FtV. Seventeen participants (intervention: n=8, control: n=9) completed all questionnaires. Mixed model analysis showed significant differences between groups on the SCL-90 DEP (P=.04) and ANX (P=.049) subscales between 6 and 12 weeks after participation started. UNIANOVA showed no significant differences. Pre-post paired sample t tests showed significant improvements after 12 weeks for the SCL-90 DEP (P=.03) and ANX (P=.046) subscales. Reported mean Web-based time per week was 2.83 with a session time of 36 min. FtV was rated a mean 7.47 (1-10 Likert scale) with a helpfulness score of 3.16 (1-5 Likert scale). All participants felt safe. Two-thirds of the intervention participants started regular health care.

CONCLUSIONS

No changes on the IES were found. SCL-90 DEP and ANX showed promising results; however, the calculated sample size was not reached (n=18). FtV functions best as a first step for adolescents and young adults in an early stage of change. FtV can be easily implemented without extensive resources and fits best in the field of public health care or national governmental care.

TRIAL REGISTRATION

Netherlands National Trial Register (NTR): NTR3692; http://www.trialregister.nl/trialreg/admin/ rctview.asp?TC=3692 (Archived by WebCite at http://www.webcitation.org/6qIeKyjA4).