Psychosocial Determinants of Cannabis Protective Behavioral Strategies: Perceived Efficacy and Social Norms

Background: In the last few years, several studies have shown that using cannabis Protective Behavioral Strategies (PBS, e.g., “Only use when you know you have nothing important to do for the rest of the day/night”) is associated with decreased cannabis use and its related consequences. Thus, identifying the determinants of cannabis PBS use may be useful to inform interventions aimed at increasing PBS use among people who use cannabis as a manner of reducing cannabis use and its related consequences. In the field of alcohol consumption, psychosocial determinants of PBS use have been well-identified. However, the psychosocial determinants of cannabis PBS are understudied. 
Regarding alcohol-PBS, it has been shown that perceiving PBS as useful to reduce alcohol-related consequences (perceived efficacy) and perceiving that peers use PBS frequently (descriptive social norm) is associated with increased personal PBS use. Moreover, it has been shown that the impact of descriptive norm on personal alcohol PBS use is partially mediated by perceived efficacy. This is, those who perceive that their peers use alcohol PBS frequently tend to think that PBS are useful and, consequently, use PBS more frequently. Nonetheless, these relationships have not been tested for cannabis PBS use, for which knowledge about their determinants is very scarce. Thus, we aimed to prospectively examine 1) the predictive value of perceived efficacy of cannabis PBS and descriptive norm of peers´ PBS use, over the personal use of cannabis PBS among young adults, and 2) the mediating role of perceived efficacy between descriptive norm and personal PBS use. 
Methods: Targeted sampling procedure was used to access a community sample of 612 young adults reporting past-month cannabis use. We followed face to face procedure for data collection. From the baseline sample, 505 participants (82.5%) responded to a 3-month follow-up survey. Since 39 participants reported not using cannabis at follow-up and did not respond to PBS items, the analytic sample in this study was 466. We conducted a hierarchical linear regression model to test objective 1. We used the PROCESS macro to test the mediating role of perceived efficacy between social norm and personal PBS use.
Results. Both, perceived efficacy of cannabis PBS to reduce cannabis-related consequences and descriptive norm of peers´ PBS use were prospective and positively associated with personal PBS use. Moreover, we found a partial mediation effect of perceived efficacy between descriptive norm and personal PBS.
Conclusions. Our findings replicate those found in the alcohol PBS field, showing the explanatory value of two important psychosocial determinants of cannabis PBS use. These results may be useful to inform interventions aimed at promoting cannabis PBS use among young adults.
This study is part of the research project Psicocann (PID2020-118229RB-I00), granted for MCIN/AEI/10.13039/501100011033 (IP: Fermín Fernández Calderón)