Cannabis is the most commonly used illicit drug among teenagers. Adolescents with social anxiety disorder have greater risk of developing adult cannabis dependence relative to those without this disorder. Cannabis use also appeared to be related to cannabis effect expectancies, and a relationship between social anxiety and cannabis effect expectancies was reported in the literature. However, further studies are required to confirm the role of cannabis effect expectancies in the relationship between social anxiety and cannabis use, especially during adolescence, the period of life during which social anxiety and cannabis use generally emerge.
A questionnaire was administered to 1,343 Belgian teenagers (M=15.7; age range: 14-18; SD=0.88; 49.59% of female). The data proceeded from the first of four waves in a longitudinal study. Several factors were studied: lifetime cannabis use, frequency of use, related problems, effects expectancies, and social anxiety. Linear and logistic regressions were performed to identify expectancies related to social anxiety and cannabis use, and mediation/moderation analyses were carried out.
First, social anxiety was shown to be negatively related to lifetime cannabis use but not to frequency and problems of use. Second, lifetime cannabis use was associated with every cannabis effects expectancy and high-order positive and negative effects expectancies. Third, social anxiety was negatively related to perceptual enhancement and craving effect expectancies and positively related to negative behavioral effects expectancies and high-order negative effects expectancies. Fourth, the study showed that relaxation and social facilitation effect expectancies and high-order positive effect expectancies may be considered moderator variables of the relation between lifetime cannabis use and social anxiety. Negative behavioral effects expectancies and high-order negative effects expectancies may be perceived as partial mediating variables.
The present study identified a negative relationship between social anxiety and lifetime cannabis use among adolescents. It also helps define the mechanisms underlying cannabis use initiation. Our data suggest that social anxiety is a potential protective factor for lifetime cannabis use in middle adolescence. Clearly, positive and negative effect expectancies play an important role in this relationship. These results support the importance of cannabis use effect expectancies in preventive programs.