A number of studies have found higher rates of various psychiatric problems among marijuana users, and there has been much debate about whether marijuana causes these problems or whether those with psychological issues are simply more likely to use it. In this study, Swiss youth were followed for two years to determine how their motive for marijuana use interacts with levels of psychological distress. Social users did not experience any more distress or psychological problems than non-users. Only those who used marijuana as a coping mechanism experienced increased psychological distress. There was no sign that either group of users got worse in terms of psychosocial issues over the two year period. The authors conclude that coping-motivated marijuana users should be targeted for mental and social health care, but “Cannabis users with social motives do not seem to need interventions to prevent psychological or psychosocial distress or life events.”

Jeannette Brodbeck et al., “Motives for cannabis use as a moderator variable of distress among young adults,” Addictive Behaviors 32, issue 8 (August 2007): 1537-1545.

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