Bidirectional associations between protective behavioral strategies for cannabis use and cannabis outcomes: A cross-lagged longitudinal approach

Although the use of cannabis Protective Behavioral Strategies (PBS) is associated with lower consumption and fewer harms, most research has relied on cross-sectional designs, leaving the within-person directionality of these associations unclear. This study examined the bidirectional associations between PBS use and cannabis outcomes (frequency, quantity, and negative consequences) over a 15-month period and explored sex differences. We employed a three-wave longitudinal design (baseline, 3-, and 15-month follow-ups) and used a targeted sampling procedure to recruit a community-based sample of young adults who reported past-month cannabis use (n = 612; M age = 21.04; 61.2% = male; 40.8% = university students). Random-intercept cross-lagged panel models disentangled stable between-person differences from within-person change and tested for sex invariance. At the between-person level, greater PBS use was associated with lower cannabis frequency, quantity, and negative consequences. At the within-person level, increased PBS use predicted subsequent reductions in cannabis use frequency, but not in quantity or consequences. Conversely, experiencing higher-than-usual negative consequences predicted subsequent increases in PBS use. No other significant cross-lagged effects were observed. Multigroup analyses revealed that these longitudinal associations were invariant across sex. Overall, findings provide novel evidence of the dynamic role of PBS, indicating that they function both as a protective factor and as a self-regulatory mechanism activated by adverse experiences. The stability of these associations across sex suggests that PBS-based interventions may operate through similar longitudinal mechanisms for men and women.