Latinx and non-Hispanic White college students

Addictive Behaviors 98 (2019) 106060

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Addictive Behaviors journal homepage: www.elsevier.com/locate/addictbeh

Demographic differences in perceived social norms of drug and alcohol use among Hispanic/Latinx and non-Hispanic White college students

T

⁎

Karlyn A. Edwards , Katie Witkiewitz, Kevin E. Vowles Department of Psychology, University of New Mexico, Albuquerque, NM, United States of America

H I GH L IG H T S

students may benefit from social norm interventions targeting alcohol use, and men and Hispanic/Latinx students may have greater benefit from social norm • All interventions targeting cannabis use. norm interventions targeting proximal (close friend) peer stimulant use may be more effective than distal (acquaintance) peer stimulant use. • Social peer use was not associated with opioid use, yet high base rate use suggests that personalized normative feedback interventions may be a more • Perceived appropriate intervention to reduce opioid use.

A R T I C LE I N FO

A B S T R A C T

Keywords: Race/ethnicity Hispanic/Latinx Social norms Opioids Substance use College students

Social norms are a modifiable treatment target that can decrease problematic alcohol use among college students. However, little is known about how social norms may be related to cannabis, opioid, and stimulant use. Further, it is not known how these relations might differ by gender and race/ethnicity. This study sought to examine the role of descriptive social norms of two peer reference groups (close friend and acquaintance) in relation to personal substance use among four substances (opioids, alcohol, cannabis, and stimulants), and if these relations may be moderated by gender or race/ethnicity in a sample of Hispanic/Latinx (H/L) and NonHispanic White (NHW) students. Participants were primarily H/L (58%), women (70%), and freshman (47%). Findings indicated that higher perceived peer substance use was associated with higher personal use for alcohol and cannabis. Higher perceived close friend stimulant use was associated with higher personal stimulant use, although perceived acquaintance stimulant use was not associated with personal stimulant use. There was no association between perceived peer opioid use and personal opioid use. Men had a stronger positive association between perceived peer cannabis use and personal use. Women had a stronger positive association between perceived acquaintance stimulant use and personal use. H/L students had a stronger positive association between perceived peer cannabis use and personal use. NHW had no significant association between perceived peer opioid use and personal use. Findings suggest that men and H/L students may be more susceptible to peer influences on cannabis and opioid use.

1. Introduction Problematic substance use among college students has increased steadily over the past decade with a corresponding increase in overdoses and deaths (Arria et al., 2013; Mallett et al., 2017). Recreational use of prescription medications, predominantly opioids, is the largest contributor to these increasing rates of overdose and overdose death on college campuses (Martins, Kim, Chen, et al., 2015; McCabe, Teter, Boyd, Knight, & Wechsler, 2005; Rozenbroek & Rothstein, 2011). In

addition, college students are significantly more likely to meet criteria for an alcohol use disorder and less likely to receive past year alcohol or drug treatment than their non-college attending peers (Blanco, Okuda, Wright, et al., 2008). Due to this, research into potential modifiable treatment targets to help reduce the negative impact of substance use across college campuses has been growing. Of most promise, there is a large body of literature examining the role of social norms (i.e. perceptions of normative peer substance use) in relation to personal substance use. Specifically, perceived peer alcohol use is the most robust

⁎ Corresponding author at: Department of Psychology, University of New Mexico, MSC03-2220 Logan Hall, Albuquerque, NM 87131-0001, United States of America. E-mail address: [email protected] (K.A. Edwards).

https://doi.org/10.1016/j.addbeh.2019.106060 Received 22 February 2019; Received in revised form 21 July 2019; Accepted 24 July 2019 Available online 24 July 2019 0306-4603/ © 2019 Elsevier Ltd. All rights reserved.

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with only one study specifically examining perceptions of peer and personal substance use among H/L and Non-Hispanic White (NHW) students. This study found perceived discrimination to be significantly associated with alcohol, cannabis, cigarette, and inhalant use in the last 30 days, as well as substance use intentions, positive drug expectancies, perceived peer approval of substance use. Further, this association was strongest among H/L as compared to NHW students, and remained significant, even after controlling for demographic factors, socioeconomic factors, language spoken, time in the United States, academic achievement, and birth country (Kulis et al., 2009). This suggests that racial/ethnic minorities, as compared to NHW students, may also be more susceptible to peer influences due to experiencing higher rates of stress related to discrimination. Furthermore, given that the H/L population is the fastest growing ethnic community in the United States and there are some Universities that have a substantial proportion of H/ L students, it is important to better understand how the differential impact of peer influences on substance use patterns may vary among this population. Taken together, little is known about the role of perceived peer use in relation to problematic substance use outside of alcohol. Specifically, cannabis, opioid, and stimulant use has been understudied in this area among college students. Further, factors such as reference group proximity, gender, and race/ethnicity in relation to these substances are not well understood. The current study sought to examine the role of descriptive social norms of two peer reference groups (close friend and acquaintance) in relation to personal substance use within the past 12 months in a number of different substances, including opioids, alcohol, cannabis, and stimulants, in H/L and NHW undergraduate students. Also, this study sought to understand if the relation between perceived peer use and personal substance use may be moderated by gender or race/ethnicity. We hypothesized that higher perceptions of both close friend and acquaintance substance use would be associated with more personal substance use across all substances. We also hypothesized that perceived close friend use would be more strongly associated with personal substance use than perceived acquaintance use across all substances. Finally, we hypothesized that these relations would be moderated by gender and race/ethnicity, with men and H/L students exhibiting a stronger positive relation between perceived peer use and personal substance use than NHW students.

mediator studied to date in the alcohol use literature, and consistently mediates quantity and frequency of personal alcohol use (Champion, Lewis, & Myers, 2015; McCabe, 2008; McCabe et al., 2005; Meisel & Goodie, 2015; Reid & Carey, 2015; Silvestri & Correia, 2016). Among these studies, higher perceptions of peer alcohol use is consistently associated with more personal alcohol use, negatively impacting academic and health outcomes (Diguiseppi et al., 2018; Lac & Donaldson, 2016; Merrill, Carey, Reid, & Carey, 2014). Social norm interventions have been used to correct student perceptions of normative peer alcohol use in order to decrease personal alcohol use (Fabiano, 2003; Haines & Barker, 2003; Perkins & Craig, 2003). These interventions have been found to be effective in decreasing problematic alcohol use among college students (Haines & Spear, 1996; Perkins & Craig, 2003; Werch et al., 2000). Research examining the temporal precedence of changes between normative drinking perceptions and drinking behavior have supported the hypothesized mechanisms, with mediation analyses indicating changes in perceived peer drinking behavior lead to changes in individual drinking behavior, which in turn promoted a more accurate perception of peer drinking behavior (Lewis, Litt, & Neighbors, 2015; Neighbors, Dillard, Lewis, Bergstrom, & Neil, 2006; Neighbors, Lewis, Labrie, et al., 2016). However, very few studies to date have examined the role of social norms among other commonly misused substances among college students (Fabiano, 2003; Perkins, 2002; Perkins & Berkowitz, 1986; Reid & Carey, 2015; Thombs & Hamilton, 2002). Of the few cross-sectional studies that have, cannabis, opioids, stimulants, and codeine cough syrup show patterns consistent with alcohol use, indicating that perceptions of peer use exceed reported personal use(Buckner, 2013; Kilmer, Walker, Lee, et al., 2006; McCabe, 2008; Meisel & Goodie, 2015; Sanders, Stogner, Seibert, & Miller, 2014). Yet, only one social norm intervention has targeted a substance other than alcohol. The intervention provided personalized normative feedback to students who endorsed past month cannabis use, and found reductions in descriptive social norms at one month follow-up, but did not find reductions in cannabis use frequency or related consequences (Elliott, Carey, & Vanable, 2014). However, the same intervention among heavy cannabis users (≥ 2 days per week) found reductions in descriptive social norms, in addition to self-reported hours and days high per week, and weeks high per month, providing preliminary evidence for the effectiveness of social norm interventions among substances other than alcohol (Riggs et al., 2018). Many modifiable factors that influence the effectiveness of normative peer feedback have been identified. For example, students can distinguish among different reference groups when assessing descriptive normative drinking behavior, and misperceptions occur regardless of reference group proximity to the individual, ranging from more demographically generic (i.e. a typical student) to more demographically specific (i.e. same gender and race/ethnicity) (Borsari & Carey, 2003; Larimer, Kaysen, Lee, et al., 2009). Furthermore, reference groups that are more socially proximal in nature (i.e. close friend) were more highly correlated with risky personal drinking behaviors than reference groups that were more socially distal in nature (i.e. acquaintance) (Collins & Spelman, 2013; Larimer et al., 2009; Lewis & Paladino, 2008). Among demographic groups, normative feedback can be more effective for women than men (LaBrie, Lac, Kenney, & Mirza, 2011; Lewis & Neighbors, 2007). Further, men have been found to be more susceptible to peer influences, such that men typically have a stronger positive relationship between perceived peer use and personal substance use as compared to women (Roberson, McKinney, Walker, & Coleman, 2018). This finding has also been replicated in a large sample of Latino students (Vaughan, Wright, Cano, & de Dios, 2018). However, Hispanic/Latinx (H/L) students have been significantly understudied in this area. Very few studies have examined race/ethnicity differences (Flom, Friedman, Kottiri, Neaigus, & Curtis, 2001; Javier, Belgrave, Hill, & Richardson, 2013; Klima, Skinner, Haggerty, Crutchfield, & Catalano, 2014; Kulis, Marsiglia, & Nieri, 2009; LaBrie et al., 2011),

2. Method 2.1. Participants Eligibility criteria required that participants were ≥ 18 years old, enrolled as an undergraduate at a large Southwestern university, and able to read and write English. All participants were recruited via large undergraduate psychology courses through an online research system. Due to small proportions of Black, Asian, American Indian/Alaska Native, and Native Hawaiian/Pacific Islander students, these racial/ ethnic groups were excluded from the current analyses, leaving NHW and H/L students for the present analyses. Data were collected from a total of 1550 participants. Data from 31 participants were excluded due to a high proportion (i.e., ≥ 75%) of missing responses, 154 participants were excluded due to performing below an 80% accuracy on the validity check questions, and 106 participants were excluded due to being older than the typical college age range (18–26). Lastly, 214 participants selecting a race/ethnicity other than NHW or H/L were excluded, leaving a total sample size of 1045 for the present analyses. The final sample was primarily women (70%), H/ L (58%), and freshmen in class standing (47%). Full demographic information for the final sample can be found in Table 1. 2.2. Procedures Students interested in completing the survey for class credit were 2

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personal substance use questions detailed in the section above.

Table 1 Sample demographic characteristics. Measure

N

Mean (SD) or percent

Age Gendera Men Women GPAa Class Yeara Freshman Sophomore Junior Senior Employmenta Working Full-time Working Part-time Not Working Ethnicity/Racea Non-Hispanic White Hispanic/Latinx Family Incomea ≤ $25,000 $26,000 – $50,000 $51,000 – $75,000 $76,000 – $99,000 ≥ $100,000

1045

19.47 (1.66)

298 735 1013

30% 70% 3.37 (0.51)

490 231 194 125

47% 22% 19% 12%

88 577 380

8% 55% 37%

441 604

42% 58%

182 245 238 146 230

18% 23% 23% 14% 22%

a

2.4. Data analysis plan All variables were inspected for outliers, with personal and perceptions of peer substance use responses Winsorized to the highest occurring mode for each variable (Reifman & Keyton, 2010). In total, four cases for personal alcohol use were Winsorized to 300, seven cases for personal opioid use were Winsorized to 30, eleven cases for personal stimulant use were Winsorized to 60, ten cases for perceived close friend opioid use and nine cases for perceived close friend stimulant use were Winsorized to 240, and lastly, ten cases for perceived acquaintance stimulant use were Winsorized to 300. Gender (coded as −0.5 = man, 0.5 = woman) and race/ethnicity (coded as −0.5 = NHW, 0.5 = H/L) were dummy coded, and continuous predictors were mean centered prior to being entered into the models (Kraemer & Blasey, 2003). All analyses were carried out using SPSS Version 25.0 (Corp, 2017). To examine differences between peer reference groups in predicting personal substance use in the past 12 months across four substance categories, eight separate negative binomial regressions were carried out (one for each peer group of the four substance categories). Negative binomial models are primarily used when outcome variables represent highly skewed count data, in which there is a high preponderance of zero counts and the variance is expected to exceed the mean. In this type of regression, the linear predictor is connected to the outcome via a natural logarithm link function to account for overdispersed data. Therefore, raw regression coefficients are converted to a log scale and interpreted as incidence rate ratios (IRRs) (Atkins, Baldwin, Zheng, Gallop, & Neighbors, 2013). IRRs describe the proportional change in the count associated with a one unit increase of the predictor. All count outcomes were checked to be sure that the variance exceeded the mean and that distributions were highly skewed towards zero. First, independent samples t-tests were used to determine that perceived close friend and acquaintance use for each substance were significantly different, providing support for analyzing the peer reference groups in separate models. Second, Pearson chi-square tests were used to examine proportional differences in reported substance use (i.e. yes/ no in the past 12 months) by gender and race/ethnicity. Lastly, the eight negative binomial regressions were estimated. The first set of regressions examined perceptions of close friend use predicting personal substance use across all four substance categories (alcohol, cannabis, opioids, stimulants), while controlling for participant age. The second set of regressions examined perceptions of acquaintance use predicting personal substance use across all four substance categories, controlling for participant age. To examine a moderation effect of gender and race/ethnicity on the relation between perceived peer substance use and personal substance use, both were entered as a moderator in the close friend and acquaintance model. Significant interactions were further probed using simple slopes to examine the relation between perceived peer and personal substance use within each gender and race/ethnicity group. Alpha levels were corrected using the family-wise error rate (0.05/8) with p ≤ .00625 indicating significance for all models. Lastly, Cook's Distance was used to measure case-specific leverage and influence on the regression line for each model. There were two cases that had values ≥1, indicating significant influence and leverage in the regression, which were removed from the analyses (Tabachnick & Fidell, 2013).

Does not add to 1045 due to missing data/no response.

provided with a URL link to the informed consent hosted on an online survey platform. To enroll, participants were required to read the informed consent and confirm that they met the stated eligibility criteria prior to accessing the study questionnaires. Participants were asked to complete a survey assessing personal and peer perceptions of substance use, and demographic characteristics. Five validity check questions were randomly placed throughout the survey and participants were required to accurately complete at least four of these questions. Responses for the current study were submitted between June 2017 and July 2018. All study procedures were reviewed and approved by the university Institutional Review Board. 2.3. Measures 2.3.1. Demographic information Demographics collected included self-reported gender (man or woman), age, race/ethnicity, class standing, family income, grade point average, and living on or off campus. 2.3.2. Personal substance use Days of use within the past 12 months for four substances were assessed. These included days of use for alcohol, cannabis, opioids (any prescription opioid), and stimulants (any prescription stimulant, cocaine, methamphetamine, MDMA/Ecstasy). For example, questions asked, ‘During the last 12 months, how often did you have any kind of drink containing alcohol?’. These were adapted from previous studies examining social norms of substance use among college students, as well as guidelines from the National Institute of Alcohol Abuse and Alcoholism (NIAAA) (McCabe, 2008; Neighbors et al., 2006; Recommended Alcohol, 2003; Sanders et al., 2014). Responses could range from 0 to 365 days. For substances that may be prescribed, questions referred specifically to “recreational use” defined as use without a prescription or more than prescribed (Smith, Dart, Katz, et al., 2013).

3. Results Means, standard deviations, and proportion of students that reported at least one day of use for each substance can be found in Table 2. As hypothesized the most distal reference group (perceived acquaintance) was observed to have the highest estimated number of days of use, followed by the most proximal reference group (close

2.3.3. Perceptions of peer use Perceptions of peer substance use were measured separately for two groups: (1) close friend of the same gender and age attending the university and (2) acquaintance of the same gender and age attending the university. The peer substance use questions were identical to the 3

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1% increase in number of alcohol and cannabis use days and a 2% increase in number of stimulant use days. The main effect of perceived acquaintance use also indicated a small and significant positive association with reported personal use for alcohol and cannabis. A one day increase in perceived acquaintance use was associated with a 0.2% increase in number of alcohol use days and a 0.5% increase in number of cannabis use days. However, perceived acquaintance stimulant use was not associated with personal stimulant use. For opioid use, there was no significant association between perceived close friend or perceived acquaintance use and reported personal use. The hypothesis that perceived close friend use would have a stronger association with reported personal substance use than perceived acquaintance use was supported for alcohol, cannabis, and stimulants, as indicated by slightly larger IRRs for the main effects of perceived close friend use. There was a larger IRR for perceived close friend opioid use as compared to perceived acquaintance opioid use, however these predictors were not significant. Among the age covariate, it was found that older age was associated more days of alcohol and stimulant use across both peer models. There was no effect of age on cannabis or opioid use in either peer model. For gender, it was hypothesized that men would have a stronger positive association between perceived peer use and personal use across all four substances. The findings provided limited support for this hypothesis. Gender of the respondent moderated the association between perceived peer cannabis use and reported personal use for both peer models. In line with the study hypothesis, simple slopes analysis revealed that for cannabis men exhibited a stronger positive relation between perceived close friend use and reported personal use (β = 0.30, 95% CI:. 22–0.37) than women (β = 0.26, 95% CI: 0.22–0.30). Contrary to study hypotheses, women reported a slightly stronger relation between perceived acquaintance cannabis use and personal use (β = 0.19, 95% CI: 0.15–0.23) than men (β = 0.18, 95% CI:. 10–0.26). Similarly, gender also moderated the association between perceived acquaintance stimulant use and personal use in the opposite direction that was hypothesized. It was found that women had a positive association between perceived acquaintance use and personal stimulant use (ß = 0.03, 95% CI: 0.02–0.04) as compared to no association among men (β = 0.01, 95% CI: −0.01–0.02). Additionally, contrary to the study hypothesis, gender did not moderate the association between perceived peer use and personal use for alcohol or opioids, or the association between perceived close friend stimulant use and personal use. Of note, there was a significant main effect of gender only for cannabis, such that men reported more days of cannabis use across both peer models.

Table 2 Sample size of reported use, and means and standard deviations of the number of days of personal, perceived close friend, and perceived acquaintance substance use in the past 12 months. Substance

N (%)a

Personal use

Perceived close friend use

Perceived Acquaintance Use

Mean (SD)b

Mean (SD)b

Mean (SD)b

70.98 (77.95) 109.90 (126.55) 17.41 (43.09) 16.28 (40.87)

81.07 (85.74) 131.63 (125.29)

Alcohol Cannabis

816 (78%) 476 (46%)

28.11 (46.71) 34.08 (82.00)

Opioids Stimulants

231 (22%) 150 (14%)

0.69 (3.45) 1.82 (8.17)

a b

35.40 (67.56) 34.77 (63.00)

Reported at least one day of recreational use. Means and standard deviations are based on the entire sample.

friend). Reported personal substance use was observed to have the lowest estimated number of days of use across all substances. t-tests examining differences between perceived close friend and perceived acquaintance use across all substances were significant [all t's (1,045) ≥ 12.83, all p's < 0.001], warranting separate models for each reference group. Pearson chi-square tests examining proportional differences in reported personal substance use in the last 12 months by gender found no differences [all χ2's (1, N = 1045) ≤ 2.292, all p's ≥ 0.130]. There were also no differences by race/ethnicity in alcohol, cannabis, or opioid use [all χ2's (1, N = 1045) ≤ 1.65, all p's ≥ 0.199]. However, there was a significant difference in reported stimulant use [17.7% vs 11.9%; χ2 (1, N = 1045) = 12.83, p = .008], such that a higher proportion of NHW students reported stimulant use in the past 12 months than H/L students. Of those reporting at least one day of recreational use in the past 12 months, 2% (n = 9) endorsed having a prescription for cannabis, 1% (n = 3) endorsed having a prescription for opioids, and 6% (n = 9) endorsed having a prescription for stimulants. This suggests that, for substances that may be prescribed, recreational use in this sample was primarily use without a prescription. Results from the negative binomial regressions partially supported the study hypotheses (see Table 3). The hypothesis that perceived close friend and acquaintance substance use would be positively associated with reported personal substance use in the past 12 months for all four substances was partially supported. Results indicated a significant and positive main effect of perceived close friend use in relation to reported personal use for alcohol, cannabis, and stimulants. Specifically, a one day increase in perceived close friend use was associated with a roughly

Table 3 Negative binomial regressions testing gender (G) and race/ethnicity (R/E) as a moderator between perceived number of days of close friend use and acquaintance use predicting days of personal use in the past 12 months among four substance categories. Alcohol Reference group Perceived close friend use (CF)

Perceived acquaintance use (A)

Predictor Intercept Agea Genderb R/Ec CFa G x CFa,d R/E x CFa,e Intercept Agea Genderb R/Ec A G x Aa,d R/E x Aa,e

IRR 27.194 1.175⁎ 0.973 0.727⁎ 1.008⁎ 0.998 1.00 31.627⁎ 1.209⁎ 0.955 0.666⁎ 1.005⁎ 0.998 1.002

Cannabis 99.99% CI 20.697–35.730 1.087–1.272 0.731–1.294 0.560–0.946 1.004–1.012 0.994–1.003 0.997–1.004 24.216–41.306 1.115–1.311 0.716–1.271 0.510–0.868 1.001–1.008 0.994–1.001 0.999–1.006

IRR

99.99% CI ⁎

30.417 1.010 0.598⁎ 0.867 1.005⁎ 1.002⁎ 1.003⁎ 38.436⁎ 1.029 0.560⁎ 0.953 1.002⁎ 1.004⁎ 1.003⁎

Notes. IRR = Incidence Rate Ratio. CI = Confidence Interval. a Mean centered, perceived peer use, e Race/ethnicity x perceived peer use, ⁎p ≤ .001.

b

4

Opioids IRR

22.874–40.447 0.935–1.091 0.449–0.795 0.667–1.126 1.003–1.007 1.000–1.005 1.001–1.006 29.079–50.805 0.949–1.116 0.422–0.742 0.735–1.236 1.000–1.004 1.001–1.006 1.001–1.006

Reference group is male,

0.650 0.943 0.951 1.065 0.997 0.998 1.012⁎ 0.540⁎ 0.947 0.944 1.358 0.990 1.006 1.016⁎ c

Stimulants 99.99% CI 0.421–1.004 0.836–1.064 0.613–1.478 0.704–1.611 0.984–1.010 0.989–1.006 1.00–1.024 0.325–0.900 0.839–1.069 0.605–1.471 0.837–2.201 0.978–1.003 0.987–1.001 1.003–1.028

IRR

99.99% CI ⁎

2.250 1.259⁎ 0.760 0.445⁎ 1.018⁎ 1.001 0.998 2.284⁎ 1.224⁎ 0.757 0.507⁎ 1.005 1.008⁎ 0.997

1.608–3.149 1.145–1.384 0.523–1.102 0.313–0.633 1.004–1.031 0.987–1.014 0.989–1.008 1.640–3.177 1.119–1.338 0.525–1.092 0.359–0.715 0.999–1.010 1.002–1.014 0.992–1.002

Reference group is Non-Hispanic White,

d

Gender x

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perceived close friend cannabis use and personal cannabis use as compared to women, suggesting that men may be more susceptible to proximal peer influences specifically with cannabis use. Previous research has posited that men may be more susceptible to peer influences as they typically report more frequent peer pressure, and fear in expressing concerns about substance use since it often makes it more difficult for men to fit in with peer networks (Suls & Green, 2003). This pattern was not observed in the current findings with alcohol use, which was unexpected given prior studies. It is possible that in the current sample, men and women were equally influenced by perceptions of peer alcohol use. Further, given that roughly 1 in 2 college students report past year cannabis use, and that alcohol use predicts initiation of cannabis use among men, it may be that men's peer networks may be more likely to integrate cannabis use into the normative culture as compared to women's peer networks (Haug, Núñez, Becker, Gmel, & Schaub, 2014). Interestingly, for cannabis and stimulants, women did have a stronger positive association between perceived acquaintance use and personal use as compared to men, suggesting that both the proximal and distal social network may contribute to increased cannabis and stimulant use among women. It is possible that this may be related to previous findings showing that women are less susceptible to peer pressure than men, indicating that women may require a higher threshold of peer pressure from both proximal and distal peer networks in order to initiate use. Overall, there was no main effect of race/ethnicity on cannabis or opioid use. There was a main effect of race/ethnicity on alcohol and stimulant use, such that NHW students reported more frequent use. When race/ethnicity was examined as moderator, it was found that H/L students had a stronger positive association between perceived peer cannabis use and personal use as compared to NHW students. For opioid use, H/L students had a positive association between perceived close friend use and personal use. These findings were in line with the study hypotheses, and suggest that H/L students may be more susceptible to proximal peer influences on cannabis and opioid use (LaBrie, Atkins, Neighbors, Mirza, & Larimer, 2012). This may be due to more frequent perceptions of discrimination, leading to higher levels of stress, which has been connected to more frequent substance use (Kulis et al., 2009). In addition, previous work has found specific social stressors, such as limited family support, gang involvement, limited economic resources, and family drug and alcohol use contributes to personal substance use (Berger Cordoso, Goldbach, Cervantes, & Swank, 2016). Therefore, it may be that these stressors also contribute to a greater need for peer support, which can place a higher importance on fitting in with others. Contrary to study hypotheses, there was no association between perceived peer opioid use and personal use for NHW students, nor was there an association between perceived acquaintance opioid use and personal use for H/L students. These findings suggest that NHW students are not susceptible to proximal or distal peer influences on opioid use, while H/L are not susceptible to distal peer influences. It is possible that NHW students perceive opioids to be more harmful than H/L students, particularly due to the ‘white-washed’ nature of media attention on the opioid epidemic, which often portrays problematic opioid use as most prevalent among NHW individuals (Netherland & Hansen, 2016). Although research has shown that problematic opioid use, overdoses, and deaths are present across urban and rural locations, race/ethnicities, and socioeconomic statuses in the United States, this may additionally contribute to why NHW students are less susceptible to peer influences on opioid use as compared to H/L students (Bechteler, Kane-Willis, & Metzger, 2017; Paulozzi, Jones, Mack, & Rudd, 2011; Rigg, Monnat, & Chavez, 2018). This is the first study to examine racial/ethnic differences in perceptions of peer and personal opioid use, therefore further research is needed to instantiate this finding. Importantly, normative data on past year rates of substance use have been collected for multiple decades through annual surveys such

Lastly, it was hypothesized that race/ethnicity would moderate the association between perceived peer use and personal substance use across all four substances, and the findings provided partial support for this hypothesis. Race/ethnicity of the respondent moderated the association between perceived peer use and reported personal use for cannabis and opioids for both peer models. In line with the study hypothesis, simple slopes analysis revealed that for cannabis, among both peer models, H/L students exhibited a stronger positive relation between perceived peer use and reported personal use (Close friend: ß = 0.32, 95% CI: 0.27–0.37; Acquaintance: ß = 0.23, 95% CI: 0.17–0.28) than NHW students (Close friend: ß = 0.23, 95% CI: 0.18–0.28; Acquaintance: ß = 0.14, 95% CI: 0.09–0.20). In addition, simple slopes analysis of opioid use revealed that H/L students exhibited a small significant positive association between perceived close friend use and reported personal use (Close friend: ß = 0.01, 95% CI: 0.003–0.02), however had no association between perceived acquaintance use and personal use (ß = −0.001, 95% CI:. -0.01–0.01). Further, contrary to the study hypothesis, NHW students did not exhibit an association between perceived peer use and personal opioid use for either peer model (Close friend: ß = −0.002, 95% CI: −0.01–0.01; Acquaintance: ß = −0.003, 95% CI:. -0.01–0.001). Race/ethnicity of the respondent did not moderate the association between perceived peer use and reported personal use for alcohol or stimulants. Of note, there was a significant main effect of race/ethnicity for both substances, such that NHW students reported more days of alcohol and stimulant use across both peer models. 4. Discussion In line with previous findings, the current study found higher perceived close friend and acquaintance use was associated with higher personal alcohol and cannabis use, suggesting that socially proximal and distal peer networks each have an impact on reported personal substance use (Napper, Hummer, Chithambo, & LaBrie, 2015; Pedersen et al., 2013; Perkins, 2002). However, among stimulant use, only perceptions of close friend use was positively associated personal stimulant use, while perceived acquaintance stimulant use was not associated with personal use. Given that stimulants had the lowest past year prevalence rate and therefore, are likely used less in a social context, it is probable that only proximal social networks may influence reported personal use. Contrary to study hypotheses, perceived close friend and acquaintance opioid use was not associated with personal opioid use. This is particularly surprising given the substantially high past year prevalence rate observed in the current sample, which suggests that close to 1 in 4 college students have misused opioids in the past year. These findings indicate that peer influences may not be a contributing factor to opioid misuse use among college students, which could be due to the limited visibility or obvious use of opioids in social contexts. It could also reflect how growing media attention and public health campaigns about opioid misuse may distort perceptions of peer opioid use in ways that does not affect perceptions of other substances (Kanouse & Compton, 2015). Of promise, previous research has found that personalized normative feedback interventions that highlight differences between personal alcohol use and normative campus alcohol use rates are as effective in reducing alcohol use as compared to social norms interventions, which highlight differences in personal use, perceived peer use, and normative campus alcohol use rates (Neighbors et al., 2016). Therefore, these findings suggest that, although personal opioid misuse is not related to peer influences, personalized normative feedback interventions may still be effective in reducing opioid misuse, given that the past year prevalence rate of the current sample (22%) greatly exceeds that of U.S. normative young adult rates (4%). Overall, there were no main effect of gender on alcohol, opioid, or stimulant use. There was a significant main effect of gender on cannabis use, with men reporting more frequent use. When gender was examined as a moderator, men reported a stronger positive association between 5

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opioid use was not associated with personal opioid use, personalized normative feedback interventions that make comparisons between personal use and national normative use may still be effective, given that the current sample had significantly higher past year opioid use in comparison to the national rates. Future research should continue to explore the role of gender and race/ethnicity in relation to susceptibility of peer influence, particularly in regard to cannabis, opioid, and stimulant use, to help better understand how to implement and tailor substance use interventions among an undergraduate population with increasing ethnic diversity. Declaration of Competing Interest None.

as the Monitoring the Future (MTF) initiative. The most recent MTF survey was released in 2017, allowing rough comparisons to be made between the current sample and normative young adult substance use prevalence rates (ages 18–26)(Schulenberg et al., 2017). For alcohol use, the current sample had a slightly higher annual prevalence rate of 78%, while the MTF survey reported a 75% annual prevalence rate. For cannabis use, the current sample had a higher annual prevalence rate at 46% as compared to MTF, which reported a 38% annual prevalence rate. For opioids, the current sample had a substantially higher annual prevalence rate at 22% as compared to MTF, which reported a 4% annual prevalence rate. For stimulants, the current sample had a slightly higher annual prevalence at 14%, as compared to MTF, which reported a 12% prevalence rate averaged across all stimulants. While these comparisons are descriptive in nature, the current sample prevalence rates of past year substance use seems to be roughly on par with normative young adult data, with the exception of opioid and cannabis use which was higher in this sample.

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4.1. Study limitations The current study has limitations. The cross-sectional design prohibits the possibility of examining predictive validity or temporal precedence of social norms and personal substance use. Although previous research has examined temporal precedence of social norms and personal alcohol use in a limited fashion, this should also be studied among other substances (Lewis et al., 2015; Neighbors et al., 2006). Second, data was gathered via retrospective self-report, which may not provide accurate reporting, particularly with perceptions of peer and personal substance use within a 12-month time period. Third, this survey may have significant selection bias as it was only administered to students enrolled in psychology courses at one University, therefore, these findings may not generalize to the broader college student population. In addition, students were compensated with class credit for completing this survey, which may not provide enough incentive for some students engaged in higher rates of substance use to participate, given evidence of low engagement in academic settings (Arria et al., 2013). Fourth, perceived peer use in all the models yielded statistically small effects on personal substance use (i.e. 1–2% changes in number of days of substance use). However, it should be noted that even these small changes in substance use over a 12-month period may be clinically significant and lead to less quantity consumed per occasion, fewer negative consequences, and improved functioning. 4.2. Conclusions This study is the first to examine the moderating role of gender and race/ethnicity between perceived peer use and personal use among alcohol, cannabis, opioid, and stimulant use. Taken together, the current findings suggest that males and H/L students may be more susceptible to proximal peer influence on cannabis and opioid use. Women and NHW students were generally less susceptible to peer influences on cannabis and opioid use. Among alcohol and stimulants, men and women, and NHW and H/L students were relatively equally influenced by peer influences, with the exception of perceived acquaintance cannabis and stimulant use which was associated with more use for women. Lastly, in comparison to national prevalence rates, the current sample reported similar past year rates of alcohol and stimulant use, higher past year cannabis use, and substantially higher past year opioid use. Although the current study is cross-sectional in nature, there are some intervention implications that may be discussed. Specifically, men, women, NHW, and H/L students may benefit equally from social norm interventions aimed at decreasing alcohol use, while men and H/ L students may have greater benefit in social norm interventions targeting cannabis use. In addition, social norm interventions using more proximal peer group norms (i.e. close friends) may be more effective, particularly for stimulant use. Further, although perceptions of peer 6

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