Are adolescents gambling with cannabis use? A longitudinal study of impulsivity measures and adolescent substance use: the TRAILS study

OBJECTIVE: This study examined (a) the predictive value of observed versus reported measures of impulsivity on the onset of cannabis use and determined if lifetime tobacco and cannabis users can be differentiated by their level of impulsivity and (b) the predictive value of observed versus reported measures of impulsivity on repeated cannabis use and determined if repeated tobacco and cannabis users can be differentiated by their level of impulsivity. METHOD: The present study involves 667 (50.5% female) adolescents assessed at two time points of the TRacking Adolescents' Individual Lives Survey (TRAILS). Adolescents in our study participated in the Bangor Gambling Task (BGT), as well as completed self-report questionnaires assessing cannabis use behavior (Mage = 16.11 years) and the Behavioral Inhibition System (BIS)/Behavioral Activation System (BAS) questionnaire (Mage = 13.56 years). RESULTS: Higher levels of BAS functioning increased the likelihood that adolescents would ever use substances such as tobacco or cannabis during their lifetime. In contrast, low BIS functioning increased the likelihood of repeated cannabis use. Repeated tobacco users did not significantly differ from lifetime users by their BIS functioning. The BGT measures were not significant in relation to lifetime or repeated use of cannabis or tobacco. CONCLUSIONS: High BAS seems to be more important for experimental substance use, whereas low BIS seems to be more important for progression into regular cannabis use specifically. In contrast to the BIS/BAS, our laboratory test of impulsivity, the BGT, is not correlated with early-onset tobacco/cannabis use. Furthermore, the BGT is not correlated with the BIS/BAS measures