Mehta, Alfonso, Delaney, & Ayotte_Associations between mixed gender friendships gender ref identity and substance use

1. ORIGINAL ARTICLE Associations Between Mixed-Gender Friendships, Gender Reference Group Identity and Substance Use in College Students Clare M. Mehta & Jacqueline Alfonso & Rebecca Delaney & Brian J. Ayotte Published online: 18 December 2013 # Springer Science+Business Media New York 2013 Abstract We investigated the associations between same- gender friendship, gender reference group identity, and substance use in college students (54 % male, M age=19.23, SD =1.23) from the northeastern United States using an online survey. Male students reported greater weekly marijuana, but not alcohol use than female students. Regression analyses revealed that having a greater proportion of same-gender friendships was associated with greater weekly alcohol use for male students and lesser weekly alcohol and marijuana use for female students. Gender reference group identity was negatively associated with weekly marijuana use for male and female students. For female students, gender reference group identity mediated the association between proportion of same-gender friendships and weekly marijuana use. Our study highlights the importance of considering the social context (e.g., the gender of friends) and individual variables relating to gender (e.g. gender reference group identity) in substance use research. Our findings fit within social constructionist models of social development that suggest participation in gendered contexts (e.g., same-gender or other-gender-peer contexts) over time cue gender-typed behaviors such as using marijuana. Keywords Gender segregation . Same-sex friendships . Cross-sex friendships marijuana use . Alcohol use . Gender identity . College students Introduction Research conducted in the United States of America (USA) has suggested that throughout childhood and early adolescence, boys engage in substance use behaviors to a greater extent than girls (Bahr et al. 2005; Silverthorn and Frick 1999). In adolescence, however, the gender gap in substance use behaviors begins to narrow (Dick et al. 2007; Silverthorn and Frick 1999; Razzino et al. 2004). One reason for the narrowing of this gender gap may be that in the USA, adolescent boys and girls spend more time in mixed-gender peer groups compared to when they were children (Monsour 2002; Poulin and Pedersen 2007). As peers are believed to be one of the most important factors in the development of substance use behaviors (Bahr, et al. 2005; Dick et al. 2007: Gaughan 2006), the change in the gender composition of the peer group from same-gender to mixed-gender during adolescence and emerging adulthood may be a key determinant in male and female college students’ drug use in the USA. The purpose of this study is to extend the research on peer influence and substance use by using regression models to examine how same- and other-gender friendships and gender reference group identity are related to substance use during emerging adulthood in the USA. Although findings from the USA may not generalize to other cultures, the prevalence of same-gender over other-gender friendships appears to be culturally univer- sal (Whiting and Edwards 1988). As such, an understanding of the associations among same- and other-gender friendships, gender reference group identity, and substance use in a sample from the USA may inform similar research in other cultures. Most of the existing literature on gender, friendships, and C. M. Mehta (*) Boston Children’s Hospital, Harvard Medical School, Emmanuel College, 400 The Fenway, Boston, MA 02115, USA e-mail: mehtac@emmanuel.edu J. Alfonso Emmanuel College, 400 The Fenway, Boston, MA 02115, USA R. Delaney West Virginia University, 54 Campus Drive, Morgantown, WV 26505, USA B. J. Ayotte University of Massachusetts, Dartmouth, 285 Old Westport Road, North Dartmouth, MA 02747, USA Sex Roles (2014) 70:98–109 DOI 10.1007/s11199-013-0334-8

2. substance use is based upon data collected using samples from the United States or Canada (for example see Dick et al. 2007: Gaughan 2006). Consequently, unless otherwise noted, literature cited in this paper is based upon studies conducted in these countries. The Development of Mixed-Gender Friendships in Adolescence and Emerging Adulthood For both boys and girls, friendships during childhood and preadolescence are largely segregated by gender (Mehta and Strough 2010). During adolescence, hetero-normative expec- tations regarding the formation of heterosexual romantic relationships lead to an increase in the amount of time spent with other-gender peers (Bukowski et al. 1999; Mehta and Strough 2009; Poulin and Pedersen 2007). Thus, the proportion of other-gender peers in male and female adolescent’s friendship networks is greater than during childhood and preadolescence (Poulin and Pedersen 2007; Strough and Covatto 2002). In fact, by 12th-grade most adolescents report having at least one other-gender friend (McDougall and Hymel 2007). The inte- gration of other-gender friends into friendship networks con- tinues through adolescence and into emerging adulthood (Mehta and Strough 2009). Emerging adulthood is the period of development from ages 18–27 (Arnett 2000). Although some emerging adults enter the workforce or armed services, many continue their education in colleges and universities. In these settings, there are ample opportunities for students to interact with same-age peers of both genders in classes, dormitories, and during social activities (Mehta and Strough 2009). For those who are heterosexual, other-gender friendships are common and dating activity is frequent during this period (Monsour 2002; Wright 1989). Thus, the peer context during later adolescence and emerging adulthood looks substantially different from the peer context in childhood (Mehta and Strough 2009). Because of the desire in adolescence and emerging adulthood to form heterosexual romantic relationships, other-gender friends may be particularly influential at this transitional developmental phase (Dick et al. 2007). Mixed-Gender Friendships and Substance Use Behavior Use of substances during adolescence has been well documented internationally. For example, The European School Survey Project on Alcohol and Other Drugs, a cross-national investigation of substance use patterns of 15- and 16-year-olds in 36 European countries and the USA, found that the average rate of alcohol use over the previous 30 days in European countries was nearly double that of students from the USA. Students from the USA, however, ranked first in marijuana use, and third in illicit drug use (Hibell et al. 2012). The Monitoring the Future (MTF) study by the National Institutes of Health in the USA, has found that lifetime prevalence rates for alcohol, marijuana and illicit drug use in 8th-, 10th- and 12th-grade students was 52 %, 31 %, and 35 %, respectively (Johnston et al. 2012). Once adolescents living in the USA transition into emerging adulthood the rate of current alcohol use (defined as use in the last 30 days) climbs to 70 %, with past month marijuana use at 19 % (Substance Abuse and Mental Health Services Administration; SAMHSA 2012). Some studies have posited that experimentation with substances may be a normative part of social development for both genders (e.g., Arndorfer and Stormshak 2008; Schulte et al. 2009). While national and international research provide data suggesting that at least a third of adolescents have en- gaged in substance use (Hibell et al. 2012; Johnston et al. 2012), gender differences exist when examining specific dimensions of such use. For example, although male and female adolescents are equally likely to have experimented with alcohol, male adolescents drink more often, more heavily, and experience more alcohol-related problems than female adolescents (Hummer et al. 2012; Huselid and Cooper 1994; Schulte et al. 2009). Male adolescents also use a higher quantity of drugs, use drugs more frequently, and tend to be overrepresented among users of marijuana and hard drugs (Kulis et al. 2002). The present study investigated gender differences in weekly alcohol and marijuana use. Researchers who adopt a social learning theory (SLT) approach to the development of risk behaviors propose that risk behaviors, such as substance use, are learned from close associates (Akers 1998; Akers et al. 1979; Steele et al. 2011; Sutherland 1939). The SLT approach to risk behaviors was developed in sociology as an expansion of Sutherland’s differential association theory (Sutherland 1939). Research suggests that people are more likely to engage in criminal behavior when they associate with others who engage in and endorse criminal behavior and when people perceive benefits and limited costs of engaging in such behavior (Akers 1998; Sutherland 1939). SLT is widely supported in the literature documenting how the peer group is significantly related to adolescents’ substance use patterns (Dick et al. 2007; Gaughan 2006; Schulte et al. 2009). Only recently, however, have researchers started investigating how the gender composition of the peer group influences substance use behaviors (Gaughan 2006; Poulin et al. 2011). As noted above, during adolescence and emerging adulthood, friendship groups are usually made up of both males and females (Mehta and Strough 2009). It is during this same period that women’s substance use behaviors increase, leading to a narrowing of the gender gap in substance use behaviors (Room 1996). Thus, it is plausible that for women, spending time with other-gender peers (i.e., men) during adolescence and emerging adulthood is associated with increased substance use behaviors during this period of development. Sex Roles (2014) 70:98–109 99

3. Along similar lines, research suggests that boys and men influence girls’ and women’s attitudes and behaviors, but girls and women do not influence boys’ and men’s attitudes and behaviors (Gaughan 2006; Maccoby 1998). As such, boys and men may exert a greater influence on the substance use behaviors of girls and women. This is supported by empirical work that finds adolescent girls who spend time with other- gender peers are at increased risk for cigarette (Malow-Iroff 2006: Mrug et al. 2011), alcohol (Dick et al. 2007; Poulin et al. 2011), and marijuana use (Andrews et al. 2002; Bahr et al. 2005; Gaughan 2006). With regards to emerging adults, the odds of binge drinking are higher for college women living in mixed-gender dorms compared to those living in same-gender dorms (Boyd et al. 2008). While spending time with other-gender peers appears to be risky for girls and women, spending time with same-gender peers seems to protect girls and women from participating in risk behaviors. Perhaps this is because girls and women engage in less substance use behavior than boys and may be less likely to encourage or condone drinking overall (Mrug et al. 2011). For boys and men, however, having same-gender friendships may be more risky. Research investigating peer influence on marijuana use found that over a 3-year assess- ment period, college men’s marijuana use was similar to that of their male friends (Andrews et al. 2002). It is possible that increased use results from males who perceive more social pressure from their same-gender peers to engage in substance use behaviors (Mrug et al. 2011). It is important to note that it is possible that emerging adult women who use substances are more likely to develop friendships with other-gender peers, and that emerging adult men who use substances are more likely to develop relationships with same-gender peers. Alternatively, both behaviors may result from other common causes such as being in college where substance use behavior is normative (Mrug et al. 2011). Taken together, the above research suggests that having other-gender friends for girls and women, and having same- gender friends for boys and men increases substance use behavior. In the present study, we investigated the associations between emerging adults’ proportion of same-gender friends and weekly alcohol and marijuana use. Proportion of Same-Gender Friends, Gender Reference Group Identity, and Substance Use Gender reference group identity can be defined as the extent to which a person identifies and psychologically connects with his or her gender, feels a subjective sense of male/femaleness, and feels his or her gender is a positive and central part of who he or she is (Kulis et al. 2002; Michaelieu 1997; Wade 2008). Research indicates that gender reference group identity is associated with proportion of same-gender friends (Mehta and Strough 2010). Associations between gender reference group identity and the selection of same-gender peers could reflect that peers have an influence in socializing gender reference group identity (Carter 1987). Thus, predominantly spending time with same-gender friends could result in a greater sense of belongingness to that group. Over time, a reciprocal process may emerge such that choosing same- gender friends increases identification with others of the same gender, which in turn strengthens the desire to spend time with same-gender friends (Mehta and Strough 2010). Although evidence suggests that gender reference group identity is associated with the number of same-gender peers in a person’s social network, the association between gender reference group identity and substance use has yet to be investigated. It is widely believed that those with more same-gender friends are likely to exhibit greater gender-typed behaviors (Arndorfer and Stormshak 2008; Martin and Fabes 2001; Rose and Rudolph 2006). In his qualitative study of British undergrad- uates, Dempster (2011) found that for men, male peer groups played a role in the maintenance and reaffirmation of masculine statuses. Qualitative research conducted in the USA (De Visser and Smith 2007) and Great Britain (Dempster 2011) found that college students believed that men and women who used alcohol were more masculine than those who didn’t use alcohol. This is supported by quantitative studies that suggest that regardless of gender, those who identify as masculine are more likely to engage in drinking behavior (Iwamoto and Smiler 2013; Iwamoto et al. 2011; Peralta et al. 2010). As such, male college students who strongly identify with other men (i.e., their own-gender reference group) may use alcohol and marijuana more than male college students who do not strongly identify with other men. While masculinity is linked with increased alcohol use, femininity is linked with de- creased alcohol use in both men and women (Chomak and Collins 1987; Huselid and Cooper 1994). If this is the case, female college students who strongly identify with other women (i.e. their own gender reference group) may use alcohol and marijuana less than female college students who do not identify with or feel similar to other women. If substance use behaviors are predominantly associated with one gender, being socialized to identify with that partic- ular gender within same- or other-gender peer groups may lead to an increase in substance use behavior. In the present study we investigated the associations between gender reference group identity and alcohol and/or marijuana use. We also investigated whether having more same-gender friends for men or more other-gender friends for women was associated with increased substance use through the socialization of gender reference group identity. The Present Study To review, the change in the gender composition of the peer group from same- to mixed-gender during emerging 100 Sex Roles (2014) 70:98–109

4. adulthood may influence male and female college students’ drug use by influencing emerging adults’ gender reference group identity. Using the social-constructionist model of gender development, which posits that gender typed behaviors and characteristics (such as substance use and gender reference group identity) are cued by the gender of those in the immediate context, and the available literature as our theoretical foundation, we investigated the associations between the gender composition of college student’s peer context, their gender reference group identity, and their substance use behaviors. Given the compelling documented differences in the rates of current alcohol (70 %) and marijuana (19 %) use among emerging adults 18–25, analyses were conducted sep- arately for alcohol and marijuana (SAMHSA 2012). Hypotheses Based on the social-constructionist model of gender development and the research reviewed above, we hypothesized that: (1) male college students would report greater weekly alcohol and marijuana use than female college students. This hypothesis is a predicted replication of earlier work. For female college students we hypothesized that: (2) reporting a greater proportion of same-gender than other-gender friends would be negatively associated with weekly alcohol and marijuana use, (3) gender reference group identity would be negatively associated with weekly alcohol and marijuana use, and (4) gender reference group identity would mediate the association between the proportion of same-gender friends and weekly alcohol and marijuana use. Specifically, we hypothesized that having a greater proportion of same-gender friends would be associated with greater gender reference group identity which in turn would be associated with greater weekly alcohol and/or marijuana use for women. For male college students we hypothesized that: (5) reporting a greater proportion of same-gender friends would be positively associated with weekly alcohol and marijuana use, (6) gender reference group identity would be positively associated with weekly alcohol and marijuana use, and (7) gender reference group identity would mediate the association between the proportion of same-gender friends and weekly alcohol and marijuana use. Specifically, we hypothesized that having a greater proportion of same-gender friends would be associated with greater gender reference group identity which in turn would be associated with greater weekly alcohol and/or marijuana use for men. Method Participants All students enrolled in introductory psychology classes (approximately 500) at a mid-sized regional university were invited to participate in the study in exchange for course credit. Data from a total of 254 students were analyzed (141 males, 113 females; 52 % male), aged 18–24 (Mage= 19.23 years, SD =1.23, Mage females=18.95 years, SD females=1.51, Mage males=18.98 years, SD males=1.37). Overall, males reported significantly more alcohol and marijuana use, higher gender identity scores, and were significantly more likely to be White compared to females (see Table 1 for significance tests). Additional descriptive statistics for the sample can be found in Table 1. Procedure This study was approved by the college’s institutional review board and adhered to the American Psychological Associa- tion’s ethical standards (American Psychological Association 2002). Participants were recruited through an introductory psychology class and received course credit for participation. Measures included in the survey were taken from previous research on same- and other-gender friendships and from the NIH MTF study. All measures were completed online using Survey Monkey and took approximately 40 min to complete. Measures Same and other-gender friendships We assessed same- and other-gender friendships using an unrestricted peer nomination measure (Mehta and Strough 2010). This measure asks participants to list the first and last initials and gender of all their closest friends and to indicate whether the friend is a friend from home or from school. We then computed scores representing participants’ proportion of same-gender friends by dividing the number of same-gender friends nominated by the total number of friends nominated. The average proportion of same-gender friends nominated by participants was .70 (Males=.72, Females=.69). Weekly alcohol use A single item taken from the MTF study assessed current weekly alcohol use. Participants were asked to report the number of times a week, on average, they use alcohol. Males reported using alcohol, on average, 1.55 times a week (Range 0–13). Females reported drinking alcohol, on average, 1.34 times per week (Range 0–5). Weekly marijuana use A single item taken from the MTF study assessed current marijuana use. Participants were asked to report the number of times on average they use marijuana per week. Males reported using marijuana, on average, 6.23 times a week Sex Roles (2014) 70:98–109 101

5. (Range=0–42). Females reported using marijuana, on average 1.36 times per week (Range=0–14). Gender reference group identity A revised version of Michaelieu’s (1997) gender identity subscale (six items) assessed participants’ affiliation with their own gender. Females answered questions about their identification with females, and males answered questions about their identification with males using a 6-point Likert scale (1= strongly disagree, 6=strongly agree). A sample item for females is “being female is an important part of my identity.” A sample item for males is “being a male is an important part of my identity.” In the present study Cronbach’s alpha was .70 for males and .81 for females. Results Data Analyses Gender differences in weekly alcohol and marijuana use were investigated using independent t-tests. Associations between proportion of same-gender friends, weekly alcohol and marijuana use, and gender reference group identity were investigated using linear regressions. Separate regressions were run for men and women and for alcohol and marijuana. Results can be found in Table 3 (female college students), and Table 4 (male college students). Variance Inflation Factor scores were below 2.0 for all models suggesting that multicollinearity of variables was not a problem. Correlations between all variables can be found in Table 2. Correlations for men and women differed. As such we conducted Fishers R to Z analyses to examine whether these differences were statistically significant. There were significant differences in the correlations between proportion of same gender friends and gender reference group identity, z=−1.70, p =.01, weekly alcohol use, z=−2.33, p =.02, and weekly marijuana use, z=3.82, p =<.001, Gender Differences in Weekly Alcohol and Marijuana Use Hypothesis 1, that male college students would report greater weekly alcohol and marijuana use than female college students, was partially supported. Specifically, while there was no significant difference in weekly alcohol use for men (M = 1.55, SD= 1.67) and women (M =1.34, SD= 1.45) t(223)= 1.01, p =. 82, men reported greater weekly marijuana use (M =6.23, SD= 8.36) compared to women (M =1.36, SD= 2.75), t(189)=5.16, p <.001. Associations Between Proportion of Same-Gender Friends, Gender Reference Group Identity, and Substance Use for Women Hypothesis 2, that proportion of same-gender friends would be negatively associated with greater weekly alcohol and marijuana, and hypothesis 3, that gender reference group Table 1 Descriptive statistics Gender reference group identity scored on a six-point Likert scale (range=1.33–5.50; possible range 1–6). Higher scores represent greater gender reference group identity. Weekly substance use scores represent participants’ self- reported estimates of the frequen- cy of use per week (range alcohol=0–13; range marijuana=0– 42). Age ranged from 18 to 23 years and proportion of same- gender friends ranged from .00 to 1.00 (possible range .00–1.00) Variable Gender Significance test Male N= 139 Female N= 111 M SD M SD t (df) p Age 19.09 1.20 19.32 1.10 .11 (249) .57 Proportion of same-gender friends .72 .19 .69 .20 1.37 (247) .22 Gender reference group identity 3.93 .58 3.53 1.06 3.59 (231) <.001 Weekly substance use Alcohol 1.55 1.67 1.34 1.45 1.01 (223) .82 Marijuana 6.23 8.36 1.36 2.75 5.16 (189) <.001 n (%) n (%) χ2 (df) p Race 13.72 (3) .01 White 117 (84.2) 76 (68.5) Black/African American 7 (5.0) 18 (16.2) Mixed 6 (4.3) 12 (10.8) Other 9 (6.5) 5 (4.5) Year in school .55 (3) .90 Freshman 82 (59.0) 67 (59.8) Sophomore 38 (27.3) 29 (27.1) Junior 16 (11.5) 10 (8.9) Senior 3 (2.2) 5 (4.5) 102 Sex Roles (2014) 70:98–109

6. identity would be negatively associated with greater weekly alcohol and marijuana use, were tested using a linear regression (See Table 3). For marijuana use, results indicated that having more same-gender friends and increased gender reference group identity were both associated with less use. For alcohol use, having more same-gender friends was associated with less use, while gender reference group identity was not related to use. Hypothesis 4, that the association between proportion of same-gender friends and weekly alcohol and marijuana use would be mediated by gender reference group identity, was tested using linear regressions (Baron and Kenny 1986) and the Sobel test. First, we examined whether the association between proportion of same-gender friends and weekly alcohol use was mediated by gender reference group identity for women. In step 1 of the mediation model, weekly alcohol use was regressed onto proportion of same-gender friends. The association between proportion of same-gender friends and weekly alcohol use was significant (β=−0.26, p =.009). In step 2, weekly alcohol use was regressed on the mediator, gender reference group identity. Results indicated that gender reference group identity was not significantly related to alcohol use (β=−0.05, p =.62). As such, the requirements for mediation were not met. This suggests that in our sample, gender reference group identity did not mediate the relationship between proportion of same-gender friends and weekly alcohol use among female college students. Next, we examined whether the association between proportion of same-gender friends and weekly marijuana use was mediated by gender reference group identity for women. In step 1 of the mediation model, weekly marijuana use was regressed onto proportion of same- gender friends. The association between proportion of same-gender friends and weekly marijuana use was significant (β=−0.38, p >.001). In step 2, we found that gender reference group identity was significantly related to weekly marijuana use (β=−0.46, p <.001); In step 3, weekly marijuana use was regressed onto proportion of same-gender friends, controlling for the mediator, gender identity. With gender identity in the model, the significance of the association between proportion of same-gender friends and weekly marijuana use was re- duced but still significant (β=−0.24, p =.02), suggesting partial mediation (see Fig. 1). A Sobel test confirmed the hierarchical regression, suggesting that gender reference group identity partially mediated the association between proportion of same-gender friends and weekly marijuana use for women, Sobel=−2.42, p =.01. Associations Between Proportion of Same-Gender Friends, Gender Reference Group Identity, and Substance Use for Men Hypothesis 5 that proportion of same-gender friends would be positively associated with greater weekly alcohol and marijuana, and hypothesis 6, that gender reference group identity would be positively associated with greater weekly alcohol and marijuana use, were tested using a linear regression (See Table 4). For marijuana use, results indicated that having more same-gender friends was not associated with greater use. However, lower gender reference group identity was associated with greater use. For alcohol use, having more same- gender friends was associated with greater use, while gender reference group identity was not related to use. Hypothesis 7, that the association between proportion of same-gender friends and weekly alcohol and marijuana use would be mediated by gender reference group identity was not supported. According to our results, the requirements for mediation were not met for either weekly alcohol use or weekly marijuana use (Baron and Kenny 1986). This suggests that in our sample, gender reference group identity did not mediate the relationship between proportion of same-gender friends and weekly alcohol use among male college students. Table 3 Predictors of self-reported weekly alcohol and marijuana use in female college students *p <.05, ** p <.01 Variables Self-reported weekly alcohol use Self-reported weekly marijuana use B SE B β B SE B β Proportion of same-gender friends −1.83 .68 −0.26** −5.10 1.36 −0.38** Gender reference group identity −0.07 .15 .05 −1.16 .25 −0.46** Total R2 .07* .26** Total F (2,95)=3.50, p =.03 (2,82)=14.32, p =<.001 Table 2 Correlations between all variables Variable 1 2 3 4 1. Proportion of same-gender friends – .31* −.26** −.38* 2. Gender reference group identity .10 – −.05 −.46** 3. Weekly alcohol use .31** .08 – .18 4. Weekly marijuana use .17 .27** .05 – Correlations for women are provided above the diagonal, correlations for men are below the diagonal * p =<.01, ** p =<.000 Sex Roles (2014) 70:98–109 103

7. Discussion Our results indicated that male college students reported greater weekly marijuana use, but not alcohol use, than female college students. We also found that proportion of same- gender friends was differentially associated with substance use for males and females. For males, the correlations between proportion of same-gender friends and alcohol use were stronger than for females, and reporting more same-gender friends was positively associated with weekly alcohol use. However, for females, reporting more same-gender friends was negatively associated with weekly marijuana and alcohol use. Correlations between proportion of same-gender friends and marijuana use were stronger for women than men. For males and females, greater gender reference group identity was negatively associated with weekly marijuana use, but was not associated with weekly alcohol use. Correlations between proportion of same-gender friends and gender reference group identity were stronger for females than males. Finally, our results suggested that gender reference group identity mediated the association between the proportion of same-gender friends and weekly marijuana use in females but not for males. Gender Differences in Weekly Alcohol and Marijuana Use We hypothesized that male college students would report greater weekly alcohol and marijuana use than female college students. This hypothesis was partially supported. Male students did not report greater weekly alcohol use than female students, but did report greater weekly marijuana use. That there was no significant difference in college men and women’s weekly alcohol use in our sample supports research that suggests the gender gap in alcohol use is closing (Capraro 2000; Dick et al. 2007; Silverthorn and Frick 1999). Hoeppner and colleagues found that college women exceeded the Na- tional Institute of Alcohol Abuse and Alcoholism’s (NIAAA) guidelines for weekly drinking limits, and that women were no different from men on exceeding daily consumption limits (Hoeppner et al. 2013). Additionally, national survey data from the USA support the narrowing of the gender gap in alcohol use in those aged 12–20, with males’ reported current alcohol use rate at 25.6 %, and female use at 24.6 % (SAMHSA 2012). Although there were no significant gender differences in weekly alcohol use, as hypothesized, male college students reported greater weekly marijuana use than female college students. This fits with research that has suggested that males are heavier substance users (Hummer et al. 2012; Mullen et al. 2007; Schulte et al. 2009). It could be that while both males and females engage in drug experimentation and use alcohol, males engage in behaviors more indicative of problem substance use, such as using illicit drugs and using drugs more frequently (i.e., more times per week). -.38**, (-.24*) .31** .46** Gender Reference Group Identity Weekly Marijuana UseProportion of Same-Gender Friends Fig. 1 Standardized regression coefficients for the association between proportion of same-gender friends and weekly marijuana use in female college students as mediated by gender reference group identity. The standardized regression coefficient between proportion of same-gender friends and weekly marijuana use with gender reference group identity in the model is in parentheses. A significant Sobel test indicated that gender reference group identity mediated the association between proportion of same-gender friends and weekly marijuana use (Sobel=−2.42, p =.01) *p <.05, ** p <.001 Table 4 Predictors of self-reported weekly alcohol and marijuana use in male college students Variables Self-reported weekly alcohol use Self-reported weekly marijuana use B SE B β B SE B β Proportion of same-gender friends 2.65 .72 .30* 7.25 4.12 .17 Gender reference group identity .23 .28 .08 −4.44 1.66 −0.27** Total R2 .08** .10** Total F (2,115)=5.03, p =.008 (2,94)=5.12, p =.008 *p <.05, ** p <.01 104 Sex Roles (2014) 70:98–109

8. Associations Between Proportion of Same-Gender Friends, Gender Reference Group Identity, and Substance Use for Women Because marijuana and alcohol use are typically believed to be masculine behaviors, we hypothesized that females with a greater proportion of other-gender friends in their friendship network would report greater weekly alcohol and marijuana use than those with a greater proportion of same-gender friends in their friendship network. We predicted this in part because females with fewer other-gender friends would be less likely to be exposed to peers (i.e., males) who engage in greater substance use. This fits with SLT explanations of deviant behavior (Akers 1998; Peralta and Steele 2010; Steele et al. 2011; Sutherland 1939). This hypothesis was supported. College- aged females with more other-gender friends in their friendship networks reported greater weekly marijuana and alcohol use than those with more same-gender friends in their peer networks. This finding is consistent with previous research that suggests that for adolescent girls, having more other-gender friends is associated with increased substance use (Bahr et al. 2005; Gaughan 2006; Poulin et al. 2011). There are several possible explanations for this finding. First, research looking at friendships and alcohol use suggests that students who drink heavily select friends who also drink heavily (Knecht et al. 2011). It could be that female college students who are frequent users of alcohol and marijuana select male friends based on the belief that males use these substances to a greater extent than females. Alternatively, female college students with other- gender friends may be more likely to use alcohol and marijuana. This explanation is consistent with peer influence and SLT models that emphasize the significant impact of peers on adolescents’ substance use behavior patterns (Akers 1998; Dick et al. 2007; Gaughan 2006). It could also be that both having other-gender friendships and using alcohol and marijuana are influenced by a third variable, such as being in college or gender reference group identity. Gender reference group identity has not previously been investigated in conjunction with substance use. However, research investigating stereotypical gender-typed traits and substance use does indicate that there is an association between femininity/expressivity and alcohol use (Chomak and Collins 1987; Huselid and Cooper 1992). As such, we hypothesized that gender reference group identity would be associated with weekly alcohol and marijuana use. In our sample, we found that gender reference group identity was not associated with women’s weekly alcohol use, but was associated with women’s weekly marijuana use. That gender reference group identity was not associated with women’s weekly alcohol use could be because of the prevalence of alcohol use among women attending college. As the present study and others suggest, the gender gap in alcohol use is narrowing (Capraro 2000; Dick et al. 2007; SAMHSA 2012; Silverthorn and Frick 1999). As alcohol use becomes normative for women in college, identifying with others of the same gender may not be protective against alcohol use. Although gender reference group identity was not associated with weekly alcohol use it was negatively associated with weekly marijuana use. This indicates that the more women identified with and felt a psychological connection to their own gender, the less frequently they used marijuana. Unlike alcohol, these findings suggest that identifying with others of the same gender may protect against marijuana use in female college students. Although having more same-gender friends is associated with substance use (Poulin et al. 2011), little is known about the potential mechanism for this association, particularly among emerging adults. Because both proportion of same-gender friends and gender reference group identity were associated with weekly marijuana use in female college students, we tested a mediation model with gender reference group identity as a mediator of proportion of same-gender friends and weekly marijuana use. We hypothesized that having a greater proportion of same gender friends would be associated with greater gender reference group identity, which in turn, would be associated with greater marijuana use. We found that gender reference group identity accounted for a significant amount of the variance in the association between proportion of same-gender friends and weekly marijuana use. Specifically, our results suggest that among female college students gender reference group identity mediates the association between proportion of same-gender friends and substance use. Having more same- gender friendships may socialize gender reference group identity, which may then reduce the likelihood of female college students using marijuana. These findings fit with social constructionist models of social development (see Deaux and Major 1987) that suggest that participation in gendered contexts (e.g., same-gender or other-gender peer contexts) over time cue gender-typed behaviors (e.g., using alcohol and/or marijuana). Associations Between Proportion of Same-Gender Friends, Gender Reference Group Identity, and Substance Use for Men As noted above, alcohol and marijuana use are typically believed to be masculine behaviors. We expected that men with more same-gender friends in their friendship network would report greater weekly alcohol and marijuana use than those with fewer same-gender friends in their friendship networks. This hypothesis was partially supported. Specifically, we found that men who reported a greater proportion of same- gender friends reported greater weekly alcohol, but not marijuana use. Men with more same- than other-gender friends in their social network may report greater weekly alcohol use because of perceived social pressure from their same-gender peers to engage in substance use behaviors (Mrug et al. 2011). This supports SLT models that propose that peers have a Sex Roles (2014) 70:98–109 105

9. substantial influence on adolescents’ substance use behavior patterns (Akers 1998; Dick et al. 2007; Schulte et al. 2009). Research from the United Kingdom suggests that masculinity is often enacted in males’ same-gender peer groups (Dempster 2011). If alcohol use is a masculine behavior enacted with in men’s same-gender peer groups, it follows that men who spend more time with other men use alcohol to a greater extent. As with female college students, there are alternative explanations for this finding. First, research looking at friendships and alcohol use suggests that students who drink heavily select friends who also drink heavily (Knecht et al. 2011). It could be that male college students who are frequent users of alcohol select same-gender friends based on the belief that men use alcohol more than women. It could also be that male college students with same-gender friends may be more likely to use substances. Finally, it could also be that having both other-gender friendships and using alcohol and marijuana are influenced by a third variable, such as being in college where substance use behavior is normative (Mrug et al. 2011), or identifying with others of the same gender. Research indicates that college men’s marijuana use is similar to their male friends’ use (Andrews et al. 2002). However, our hypothesis that college men with a greater proportion of same gender friends would report greater weekly marijuana use was not supported. This finding suggests that although college men’s marijuana use may be similar to that of their friends, having more male than female friends is not associated with an increase (or decrease) in weekly marijuana use. We hypothesized that gender reference group identity would be associated with weekly alcohol and marijuana use in men. Gender reference group identity was not associated with weekly alcohol use in male college students. While gender reference group identity may be a component of masculinity, it may not be associated with correlates of masculinity such as alcohol use because it is an internal rather than external component of gender. Specifically, having an internal sense of belonging and connection with those of the same gender does not necessary require a person to publicly enact stereotypically masculine behaviors such as alcohol use. Contrary to our prediction, gender reference group identity was negatively associated with weekly marijuana use in male college students. That gender reference group identity was negatively associated with weekly marijuana use is inconsistent with previous research that has found positive associations between substance use and masculinity (Iwamoto and Smiler 2013; Kulis et al. 2002). One possible explanation of this finding is that males who identify less with their gender reference-group experience gender-role stress. Gender-role stress occurs when people feel as though they are failing to live up to socially sanctioned gender scripts (Copenhaver and Eisler 1996), and is associated with substance use (Capraro 2000; Monk and Ricciardelli 2003). Gender-role stress may lead to substance use for two different reasons. First, a male experiencing gender-role stress may “self-medicate” by using marijuana to cope (Courtenay 2000; Monk and Ricciardelli 2003). Second, a male experiencing gender-role stress may use marijuana in an attempt to demonstrate their masculinity. Research suggests that men who feel inadequate about their masculinity drink alcohol to excess to enhance their masculine status (Dempster 2011; De Visser and Smith 2007; Iwamoto et al. 2011; Peralta 2007). Alternatively, gender reference group identity and weekly marijuana use could be negatively associated because smoking marijuana may be a less masculine behavior than drinking alcohol. This could also explain why proportion of same- gender friends was not associated with weekly marijuana use. Among teenage males, traditional masculinity was found to contribute to heavy drinking but not marijuana use (Lye and Waldron 1998). The finding that gender reference group identity was negatively related to weekly marijuana use for male college students fits with popular stereotypes and media representations of male marijuana users as “laid back” and non-aggressive. Limitations and Future Directions When interpreting the results of the current study, the follow- ing limitations should be taken into consideration. First, our sample was relatively small, and because of this we may not have had enough statistical power to detect associations between variables. However, our results contribute to the literature by proposing a mechanism through which the gender of friends may influence substance use. Second, similar to many studies on both friendships and substance use, we rely on self- report measures. These reports may not accurately reflect college student’s actual weekly marijuana and alcohol use as they may over or underestimate their weekly substance use. It is likely that college students, especially heavy substance users, forget the number of times they typically use alcohol or marijuana in a given week. In addition, the same- and other- gender friendship measure may not accurately capture the number of same- and other-gender friends with whom college students spend time. College students may nominate friends who they rarely see, or with whom they are not very close. To address both of these issues, future research could use mo- mentary sampling methodology that allows for real-time reporting of both social context and substance use. Third, our data is cross-sectional and did not benefit from a random sampling method; as such, we cannot determine whether a person’s proportion of same-gender friends or gender identity influence substance use, or if substance use influences a person’s proportion of same-gender friends and gender identity. It will be important for future studies to employ a longitudinal design that will help us elucidate the direction of these associations. Fourth, although we were interested in investigating same-and other- gender friendships, gender identity, and substance use in college students due to the higher rate of substance use in college (versus non-college emerging adults), 106 Sex Roles (2014) 70:98–109

10. our findings may not generalize to those who choose not to pursue a higher education. It is also important to note that participants were recruited from an introductory psychology class, and as such are primarily first year students. Our findings therefore may not generalize to other college students. Future research should investigate friendships, gender identity, and substance use in emerging adults who are further along in their college careers and who are in the workforce, where drinking and drug use may be less normative. Fifth, although sexual orientation was assessed, we did not manage to recruit enough sexual minorities to be able to examine how the associations between same-and other gender friends, gender identity, and substance use are similar differ in non- heterosexual college students. Those who identify as gay or lesbian may have more other-gender friends than heterosex- uals (Diamond and Dubé 2002) and may be more likely to engage in substance use (Marshal et al. 2008). Conclusion Our study highlights the importance of including the gender of peers when conducting research or developing theoretical models of peer networks and substance use in college students. Interventions targeting substance use behaviors in college students should not only consider the gender composition of student’s social networks, but should also include peers in inter- vention efforts, as peers may be more effective at limiting drug use than authority figures (Andrews et al. 2002; Room 1996). Our study also highlights the importance of moving beyond binary gender measures to consider socialized gender, such as gender reference group identity, when looking for gender differences in substance use behaviors. Our findings also provide potential avenues for substance use interventions. For male college students who identify as masculine, interventions that encourage healthy masculine behaviors such as engaging in athletic activities and sports may provide an alternative for substance use as a way for constructing masculine identities (De Visser and Smith 2007). For female college students, interventions that promote internal feelings of connection with one’s gender, as well as increased opportunities to socialize with same-gender peers, may help reduce substance use. Acknowledgement The authors would like to thank the two anony- mous reviewers who provided feedback on earlier versions of this man- uscript. We would also like to thank Grant Kuehl, Kelly R. Smith, and Danielle Rose for their comments. References Akers, R. L. (1998). Social learning and social structure: A general theory of crime and deviance. Boston: Northeastern University. Akers, R. L., Krohn, M. D., Lanza-Kaduce, L., & Radosevich, M. (1979). Social learning and deviant behavior: A specific test of a general theory. American Sociological Review, 44, 636–655. doi:10.2307/ 2094592. American Psychological Association (2002). Ethical principles of psy- chologists and code of conduct. Retrieved from http://www.apa.org/ ethics/code/index.aspx. Andrews, J. A., Tildesley, E., Hops, H., & Li, F. (2002). The influence of peers on young adult substance use. Health Psychology, 21, 349– 357. doi:10.1037/0278-6133.21.4.349. Arndorfer, C. L., & Stormshak, E. A. (2008). Same-sex versus other-sex best friendship in early adolescence: Longitudinal predictors of antisocial behavior throughout adolescence. Journal of Youth and Adolescence, 37, 1059–1070. doi:10.1007/s10964-008-9311-x. Arnett, J. J. (2000). Emerging adulthood: A theory of development from the late teens through the twenties. American Psychologist, 55, 469– 480. doi:10.1037//0003-066X.55.5.469. Bahr, S. J., Hoffmann, J. P., & Yang, X. (2005). Parental and peer influences on the risk of adolescent drug use. Journal of Primary Prevention, 26, 529–551. doi:10.1007/s10935-005-0014-8. Baron, R. M., & Kenny, D. A. (1986). The moderator-mediator variable distinction in social psychological research: Conceptual, strategic, and statistical considerations. Journal of Personality and Social Psychlogy, 51, 1173–1182. doi:10.1037/0022-3514.51.6.117. Boyd, C. J., McCabe, S. E., Cranford, J. A., Morales, M., Lange, J. E., Reed, M. B., Ketchie, J. M., & Scott, M. S. (2008). Heavy episodic drinking and its consequences: The protective effects of same-sex, residential living-learning communities for undergraduate women. Addictive Behaviors, 33, 987–993. doi:10.1016/j.addbeh.2008.03. 005. Bukowski, W. M., Sippola, L. K., & Hoza, B. (1999). Same and other: Interdependency between participation in same- and other-sex friendships. Journal of Youth and Adolescence, 28, 439–459. doi: 10.1023/a:1021664923911. Capraro, R. L. (2000). Why college men drink: Alcohol, adventure, and the paradox of masculinity. Journal of American College Health, 48, 307–315. doi:10.1080/07448480009596272. Carter, D. B. (1987). The roles of peers in sex role socialization. In D. B. Carter (Ed.), Current conceptions of sex roles and sex typing: Theory and research (pp. 101–121). New York: Praeger Publishers. Chomak, S., & Collins, R. L. (1987). Relationship between sex-role behaviors and alcohol consumption in undergraduate men and women. Journal of Studies on Alcohol, 48, 194–201. Copenhaver, M. M., & Eisler, R. M. (1996). Masculine gender role stress: A perspective on men’s health. In P. M. Kato & T. Mann (Eds.), Handbook of diversity issues in health psychology (pp. 219–235). New York: Plenum Press. doi:10.1007/978-0-585-27572-7_12. Courtenay, W. H. (2000). Constructions of masculinity and their influence on men’s well-being: A theory of gender and health. Social Science & Medicine, 50, 1385–1401. doi:10.1016/S0277-9536(99)00390-1. De Visser, R. O., & Smith, J. A. (2007). Alcohol consumption and masculine identity among young men. Psychology & Health, 22, 595–614. doi:10.1080/14768320600941772. Deaux, K., & Major, B. (1987). Putting gender into context: An interac- tive model of gender-related behavior. Psychological Review, 94, 369–389. doi:10.1037/0033-295X.94.3.369. Dempster, S. (2011). I drink, therefore I’m man: Gender discourses, alcohol and the construction of British undergraduate masculinities. Gender & Education, 23, 635–653. doi:10.1080/09540253.2010.527824. Diamond, L. M., & Dubé, E. M. (2002). Friendship and attachment among heterosexual and sexual-minority youths: Does the gender of your friend matter? Journal of Youth and Adolescence, 31, 155– 166. doi:10.1023/a:1014026111486. Dick, D. M., Pagan, J. L., Holliday, C., Viken, R., Pulkkinen, L., Kaprio, J., & Rose, R. J. (2007). Gender differences in friends’ influences on adolescent drinking: A genetic epidemiological study. Alcoholism, Clinical and Experimental Research, 31, 2012–2019. doi:10.1111/j. 1530-0277.2007.00523.x. Sex Roles (2014) 70:98–109 107

11. Gaughan, M. (2006). The gender structure of adolescent peer influence on drinking. Journal of Health and Social Behavior, 47, 47–51. doi: 10.1177/002214650604700104. Hibell, B., Guttormsson, U., Ahlström, S., Balakireva, O., Bjarnason, T., Kokkevi, A., & Kraus, L. (2012). The 2011 ESPAD report: Substance use among students in 36 European countries. Retrieved from: http://www.espad.org/Uploads/ESPAD_reports/2011/The_ 2011_ESPAD_Report_FULL_2012_06-08.pdf. Hoeppner, B. B., Paskausky, A. L., Jackson, K. M., & Barnett, N. P. (2013). Sex differences in college student adherence to NIAAA drinking guidelines. Alcoholism, Clinical and Experimental Research, 37, 1779–1786. doi:10.1111/acer.12159. Hummer, J. F., LaBrie, J. W., Lac, A., Sessoms, A., & Cail, J. (2012). Estimates and influences of reflective opposite-sex norms on alcohol use among a high-risk sample of college students: Exploring Greek- affiliation and gender effects. Addictive Behaviors, 37, 596–604. doi:10.1016/j.addbeh.2011.11.027. Huselid, R. F., & Cooper, M. L. (1992). Gender roles as mediators of sex differences in adolescent alcohol use and abuse. Journal of Health and Social Behavior, 33, 348–362. doi:10.1037/0021-843X.103.4. 595. Huselid, R. F., & Cooper, M. L. (1994). Gender roles as mediators of sex differences in expressions of pathology. Journal of Abnormal Psychology, 103, 595–603. doi:10.1037/0021-843X.103.4.595. Iwamoto, D. K., & Smiler, A. P. (2013). Alcohol makes you macho and helps you make friends: The role of masculine norms and peer pressure in adolescent boys’ and girls’ alcohol use. Substance Use and Misuse, 48, 371–378. doi:10.3109/10826084.2013.765479. Iwamoto, D. K., Cheng, A., Lee, C. S., Takamatsu, S., & Gordon, D. (2011). “Man-ing” up and getting drunk: The role of masculine norms, alcohol intoxication and alcohol-related problems among college men. Addictive Behaviors, 36, 906–911. doi:10.1016/j. addbeh.2011.04.005. Johnston, L. D., O’Malley, P. M., Bachman, J. G., & Schulenberg, J. E. (2012). Monitoring the future national results on adolescent drug use: Overview of key findings, 2011. Ann Arbor: Institute for Social Research, The University of Michigan. Knecht, A. B., Burk, W. J., Weesie, J., & Steglich, C. (2011). Friendship and alcohol use in early adolescence: A multilevel social network approach. Journal of Research on Adolescence, 21, 475–487. doi: 10.1111/j.1532-7795.2010.00685.x. Kulis, S., Marsiglia, F. F., & Hecht, M. L. (2002). Gender labels and gender identity as predictors of drug use among ethnically diverse middle school students. Youth and Society, 33, 442–475. doi:10. 1177/0044118X02033003005. Lye, D. N., & Waldron, I. (1998). Relationships of substance use to attitudes toward gender roles, family, and cohabitation. Journal of Substance Abuse, 10, 185–198. doi:10.1016/S0899-3289(99)80133-3. Maccoby, E. E. (1998). The two sexes: Growing up apart, coming together. Cambridge: Belknap Press/Harvard University Press. Malow-Iroff, M. S. (2006). Cross-sex best friendship influences on early adolescent cigarette and alcohol expectancies and use. The Journal of Psychology, 140, 209–227. doi:10.3200/JRLP.140.3.209-227. Marshal, M. P., Friedman, M. S., Stall, R., King, K. M., Miles, J., Gold, M. A., Bukstein, O. G., & Morse, J. Q. (2008). Sexual orientation and adolescent substance use: A meta-analysis and methodological review. Addiction, 103, 546–556. doi:10.1111/j.1360-0443.2008.02149.x. Martin, C. L., & Fabes, R. A. (2001). The stability and consequences of young children’s same-sex peer interactions. Developmental Psychology, 37, 431–446. doi:10.1037/0012-1649.37.3.431. McDougall, P., & Hymel, S. (2007). Same-gender versus cross-gender friendship conceptions: Similar or different? Merrill-Palmer Quarterly, 53, 347–380. doi:10.1353/mpq.2007.0018. Mehta, C. M., & Strough, J. (2009). Sex segregation in friendships and normative contexts across the life span. Developmental Review, 29, 201–220. doi:10.1016/j.dr.2009.06.001. Mehta, C., & Strough, J. (2010). Gender segregation and gender-typing in adolescence. Sex Roles, 63, 251–263. doi:10.1007/s11199-010-9780-8. Michaelieu, Q. (1997). III. Female identity, gendered parenting and adolescent women’s self-esteem. Feminism & Psychology, 7, 328– 333. doi:10.1177/0959353597073005. Monk, D., & Ricciardelli, L. A. (2003). Three dimensions of the male gender role as correlates of alcohol and cannabis involvement in young Australian men. Psychology of Men & Masculinity, 4, 57–69. doi:10.1037/1524-9220.4.1.57. Monsour, M. (2002). Women and men as friends: Relationships across the life span in the 21st century. Mahwah: Lawrence Erlbaum Associates Publishers. Mrug, S., Borch, C., & Cillessen, A. H. N. (2011). Other-sex friendships in late adolescence: Risky associations for substance use and sexual debut. Journal of Youth Adolescence, 40, 875–888. doi:10.1007/ s10964-010-9605-7. Mullen, K., Watson, J., Swift, J., & Black, D. (2007). Young men, masculinity and alcohol. Drugs: Education, Prevention & Policy, 14, 151–165. doi:10.1080/09687630600997816. Peralta, R. (2007). College alcohol use and the embodiment of hegemonic masculinity among European American men. Sex Roles, 56, 741– 756. doi:10.1007/s11199-007-9233-1. Peralta, R. L., & Steele, J. L. (2010). Non-medical prescription drug use among US college students at a midwest university: A partial test of social learning theory. Substance Use and Misuse, 45, 865–887. doi: 10.3109/10826080903443610. Peralta, R. L., Steele, J. L., Nofziger, S., & Rickles, M. (2010). The impact of gender on binge drinking behavior among college students attending a midwestern university: An analysis of two gender measures. Feminist Criminology, 5 , 355–379. doi:10.1177/ 1557085110386363. Poulin, F., & Pedersen, S. (2007). Developmental changes in gender composition of friendship networks in adolescent girls and boys. Developmental Psychology, 43, 1484–1496. doi:10.1037/0012- 1649.43.6.1484. Poulin, F., Denault, A. S., & Pedersen, S. (2011). Longitudinal associations between other-sex friendships and substance use in adolescence. Journal of Research on Adolescence, 21, 776–788. doi:10. 1111/j.1532-7795.2011.00736.x. Razzino, B. E., Ribordy, S. C., Grant, K., Ferrari, J. R., Bowden, B. S., & Zeisz, J. (2004). Gender-related processes and drug use: Self ex- pression with parents, peer group selection, and achievement moti- vation. Adolescence, 39, 167–177. Room, R. (1996). Gender roles and interactions in drinking and drug use. Journal of Substance Abuse, 8, 227–239. doi:10.1016/S0899- 3289(96)90271-0. Rose, A. J., & Rudolph, K. D. (2006). A review of sex differences in peer relationship processes: Potential trade-offs for the emotional and behavioral development of girls and boys. Psychological Bulletin, 132, 98–131. doi:10.1037/0033-2909.132.1.98. Schulte, M. T., Ramo, D., & Brown, S. A. (2009). Gender differences in factors influencing alcohol use and drinking progression among adolescents. Clinical Psychology Review, 29, 535–547. doi:10. 1016/j.cpr.2009.06.003. Silverthorn, P., & Frick, P. J. (1999). Developmental pathways to antisocial behavior: The delayed-onset pathway in girls. Development and Psychopathology, 11, 101–126. doi:10.1017/s0954579499001972. Steele, J. L., Peralta, R. L., & Elman, C. (2011). The co-ingestion of nonmedical prescription drugs and alcohol: A partial test of social learning theory. Journal of Drug Issues, 41, 561–586. Strough, J., & Covatto, A. M. (2002). Context and age differences in same- and other-gender peer preferences. Social Development, 11, 346–361. doi:10.1111/1467-9507.00204. Substance Abuse Mental Health Services Administration. (2012). Results from the 2011 National Survey on Drug Use and Health: Summary of national findings, NSDUH series H-44, HHS publication no. 108 Sex Roles (2014) 70:98–109

12. (SMA) 12–4713. Rockville: Substance Abuse and Mental Health Services Administration. Sutherland, E. H. (1939). Principles of criminology. Chicago: J.B. Lippincott Company. Wade, J. C. (2008). Masculinity ideology, male reference-group identity dependence, and African American men’s health-related attitudes and behaviors. Psychology of Men & Masculinity, 9, 5–16. doi:10. 1037/1524-9220.9.1.5. Whiting, B., & Edwards, C. P. (1988). A cross-cultural analysis of sex differences in the behavior of children aged 3 through 11. In G. Handel (Ed.), Childhood socialization (pp. 281–297). Hawthorne: Aldine de Gruyter. Wright, P. (1989). Gender differences in adults’ same- and cross-gender friendships. In R. G. Adams & R. Blieszner (Eds.), Older adult friendship: Structure and process (pp. 197–221). Thousand Oaks: Sage Publications. Sex Roles (2014) 70:98–109 109

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