انگیزه استفاده از ماری جوانا و اضطراب اجتماعی در میان بزرگسالان جوان مصرف کننده ماری جوانا

Given the high rates of co-occurring marijuana use and social anxiety, the present investigation examined the relations among marijuana use motives, marijuana use and problems, and social anxiety in 159 (54.7% female) young adults (Mage = 18.74, SD = 1.20). As expected, after covarying for a number of variables related to both marijuana use and social anxiety (e.g. gender, alcohol use problems, anxiety sensitivity), social anxiety predicted greater numbers of marijuana use problems. Interestingly, social anxiety was not related to marijuana use frequency. Also consistent with prediction, social anxiety was a significant predictor of coping and conformity motives for marijuana use above and beyond relevant variables. Finally, coping motives for marijuana use mediated the relation between social anxiety and marijuana use problems. These data provide novel evidence for the unique effects of coping-motivated marijuana use in the link between marijuana-related impairment and social anxiety.

Marijuana is the most commonly used illicit drug in the United States (U.S.) and internationally (Project MATCH Research Group, 2004). The use of marijuana is particularly common among young adults, with increasing prevalence rates being reported through the 1990's (Johnson, O'Malley, & Bachman, 2001). Marijuana use in college students is especially high with 60–73% of college students reporting lifetime use of the substance (Bell et al., 1997 and McMillan and Conner, 2002) and approximately one-third of college students endorsing current use (Kilmer et al., 2006). These high rates of marijuana use among young adults are cause for concern given that marijuana is associated with a variety of problems in social, health, and occupational/educational realms (Reilly, Didcott, Swift, & Hall, 1998). Research has begun to identify factors related to marijuana use among young adults. Negative emotional states in general, and anxiety in particular, appear to convey risk for use (Patton et al., 2002). According to tension-reduction models, individuals use substances to decrease negative affect states like anxiety (Conger, 1956). Consistent with this model, marijuana users report increased use during times of affective distress (Kaplan, Martin, Johnson, & Robbins, 1986) and relief from tension is the most common reason given for their marijuana use (Hathaway, 2003 and Reilly et al., 1998). The expectation that using marijuana will reduce negative affect is associated with marijuana use among undergraduates (Schafer & Brown, 1991). In regard to anxiety more specifically, marijuana users appear to use marijuana because they believe that the drug helps to manage anxiety (Hathaway, 2003, Ogborne et al., 2000 and Zvolensky et al., 2006). Social anxiety is one form of anxiety that is associated with particularly high rates of problematic marijuana use. Social anxiety refers to a type of anxiety experienced in or in anticipation of social and/or performance situations for fear of negative evaluation. Recent studies have suggested that marijuana dependence is associated with high rates of social anxiety (Buckner et al., in press). For example, the National Comorbidity Study (NCS) indicated that individuals with social anxiety are seven times more likely to experience marijuana-related impairment relative to the general population ( Agosti, Nunes, & Levin, 2002). The NCS data also indicate that there may be some specificity between marijuana use problems and social anxiety, as the rate of marijuana dependence among individuals with social anxiety disorder was more than twice that of any other anxiety disorder. In a longitudinal investigation, after controlling for relevant Axis I psychopathology, adolescent social anxiety disorder (but not other anxiety or depressive disorders) was linked to greater rates of marijuana dependence at age 30 ( Buckner et al., in press). These data further support the contention that social anxiety increases risk for marijuana use disorders. Consistent with studies focused on clinical conditions, other reports indicate that daily marijuana users report significantly higher levels of social anxiety symptoms than individuals who use marijuana less regularly ( Oyefeso, 1991) and that college students with greater social anxiety symptomatology demonstrate greater numbers of marijuana use problems ( Buckner et al., 2006 and Buckner et al., 2006). Although there is a link between social anxiety and marijuana use problems in clinical ( Agosti et al., 2002, Buckner et al., in press and Lynskey et al., 2002) and college samples ( Buckner et al., 2006 and Buckner et al., 2006) it remains unclear whether social anxiety is related to a greater frequency of marijuana use. We know of only one study that has examined the relation between frequency of marijuana use and social anxiety ( Oyefeso, 1991). This report examined social anxiety among male undergraduate marijuana users and found daily marijuana users demonstrated higher levels of social anxiety relative to individuals who used marijuana less frequently. Although this study is limited by the exclusion of female marijuana users, this finding suggests that at least some socially anxious marijuana users may use marijuana more frequently than non-socially anxious marijuana users. The question arises as to why social anxiety, in particular, is associated with such high rates of marijuana-related impairment. Uncovering pathways through which marijuana-related impairment may emerge among socially anxious individuals is a critical step for research in this area. Motivational models of substance use posit that substance use motivated by different needs represents distinct behaviors as a function of the ability of the substance to fulfill the particular need (Cooper, Frone, Russell, & Mudar, 1995). Thus, different motives are associated with unique patterns of use, use consequences, etc. Two motives, in particular, may be related to social anxiety. First, socially anxious individuals may be vulnerable to using marijuana for coping motives (i.e., to regulate negative affective states). Although we know of no studies directly testing this hypothesis, anxious individuals appear to be at risk for coping-motivated marijuana use. For instance, the perceived ability to cope with stress has been found to moderate the relation between marijuana use problems and social anxiety among college undergraduates (Buckner, Schmidt, Bobadilla et al., 2006). Further, other anxiety conditions have been linked to coping motives for marijuana use (Bonn-Miller et al., 2007 and Comeau et al., 2001). Second, socially anxious individuals may be particularly vulnerable to conformity motives (i.e., using marijuana to avoid social censure). In fact, socially anxious undergraduates with the greatest numbers of substance-using friends have been found to demonstrate greater rates of marijuana use problems (Buckner, Mallott et al., 2006). However, given the cross-sectional nature of those data, it is unclear whether this finding reflects coping or conformity motives. Socially anxious individuals may use marijuana to cope with negative affect and then seek out marijuana-using friends to avoid negative evaluation by peers that do not use marijuana. Alternatively, socially anxious individuals may engage in conformity-motivated marijuana use, using marijuana to avoid negative evaluation by marijuana-using peers. To the extent social anxiety is related to problematic marijuana use, it is possible that coping motives could mediate this association. Using marijuana to cope with negative affectivity may limit, or forestall altogether, more adaptive mood management strategies among active marijuana users. If socially anxious young adults use marijuana to cope with distressing emotional symptoms, they may learn to rely on the drug to: (1) gain “entry” into social situations in which marijuana is present, (2) manage anxiety reactions in anticipation of and/or during social situations, and/or (3) avoid social interactions by using marijuana rather than attending social situations (e.g., class, work, social functions). In so far as this behavior pattern is effective in minimizing negative affect, over time these individuals will presumably be at greater risk for marijuana use problems. However, given mixed data regarding whether conformity motives are related to marijuana use behaviors (Bonn-Miller et al., 2007 and Simons et al., 1998), it is unlikely that conformity motives would play a mediational role in the relation between social anxiety and marijuana use frequency or problems. The present investigation was designed to test four interrelated research aims focused on explicating the associations between social anxiety and marijuana factors among young adults. First, we investigated whether social anxiety would be related to marijuana use frequency and problems above and beyond variables that are associated with social anxiety and/or marijuana-related variables. We examined whether social anxiety was related to frequency of marijuana use above and beyond the effects of gender, anxiety sensitivity (AS; the extent to which an individual believes symptoms of anxiety have harmful consequences) (Reiss & McNally, 1985), obsessive-compulsive (OC) symptoms, alcohol use quantity, and alcohol and marijuana use problems as prior works suggests these constructs are related to both social anxiety and marijuana use (e.g., Agosti et al., 2002, Bonn-Miller et al., 2007, Buckner et al., 2006 and Crum and Anthony, 1993). We also investigated whether social anxiety would be related to marijuana use problems after controlling for gender, AS, OC symptoms, alcohol use quantity, alcohol use problems, and frequency of marijuana use. Consistent with prior work (Buckner et al., 2006, Buckner et al., 2006 and Oyefeso, 1991), it was hypothesized that social anxiety would be related to greater frequency of marijuana use as well as greater number of marijuana use problems. Second, given past data suggesting that social anxiety is linked to marijuana-related impairment in women, but not in men (Buckner, Mallott et al., 2006), we examined the moderational effects of gender on the association between social anxiety and marijuana use problems. Third, we tested whether social anxiety was associated with particular marijuana use motives. In line with past research in this area (Buckner et al., 2006 and Buckner et al., 2006), it was hypothesized that social anxiety would be related to coping and conformity motives, but not other motives, after controlling for variables related to both social anxiety and marijuana use (e.g., gender, alcohol use behaviors, marijuana use behaviors). Finally, we examined whether marijuana motives mediated the relation between social anxiety and marijuana use behaviors. In light of past mediational findings in other populations (Simons, Gaher, Correia, Hansen, & Christopher, 2005) and indirect evidence of mediation with other anxiety conditions (Bonn-Miller et al., 2007 and Comeau et al., 2001), we hypothesized that coping motives would mediate any association between social anxiety and marijuana use behaviors.