The role of parents, peers and partners in cannabis use and dependence trajectories among young adult frequent users

In a 3-year qualitative longitudinal study the role of social relationships in cannabis use and dependence in young adults (all frequent users at baseline) was explored. Overall, cannabis use and dependence declined. Changes in use were, for a considerable part, attributable to processes and life events in social relationships with peers and partners, while parents had little influence. Negatively experienced events often triggered increased use and positively experienced events decreased use. Participants often adapted their use to others, depending on associate’s use. Underlying mechanisms appear related to both socialization and selection. Gender-specific processes occurred, particularly with regard to partners; females selected using partners and males nonusing partners, and subsequently cannabis use increased (females) or decreased (males) by socialization. Transitions in cannabis dependence could be explained by using peers, cohabitation and, for females, a new partnership. Persistent and newly nondependent participants were less susceptible to social influences than dependent interviewees.