Abstract
Structured interviews were conducted to identify factors that contribute to changes in frequency of personal cannabis use (increases, decreases or abstinences). Sixty cannabis users were recruited from locations throughout England (mean duration of use: 14.1 years). Among those who gave reasons for escalating their cannabis use, a large majority (79%) cited the importance of increased use by others. Approximately one-third cited the importance of a change in circumstances that provided more opportunities to use the drug, and a similar proportion claimed a role for the perceived beneficial effects of the drug. The reasons given for reducing or abstaining were more diverse, but changed circumstances were again highlighted (by 55% and 73% respectively). Reductions primarily followed changes to living arrangements, peer relations or employment; in contrast, changes precipitating abstention were more transient. Negative health effects were considered relevant by 31% of reducers and by the same proportion of those who had ever abstained. The results suggest that perceived external constraints play important roles in both upward and downward changes in cannabis use; that perceived functional effects influence escalation; and that concerns about addiction and health are salient to reduced use.