Cannabis use has become common, but we still understand little about how and why people use cannabis. This paper theorises the relationship between cannabis use and social identity, suggesting that cannabis use is an important aspect of many people's identities, and that the reasons for, or meaning, of cannabis use change and vary, over time and by situation. If cannabis use is important to people's identities, then this needs to be understood in the context of a dynamic theory of social identity. Also, issues related to social identity need to be properly understood if we are to formulate rational social policies dealing with cannabis use.

Aims. To examine cannabis users’ patterns of use, their experiences of the positive and negative effects of use, their use of other substances and possible health risks, in the context of increased prevalence of use. Methods. A snowball sample of student cannabis users in the South East England (n = 176) were interviewed with an extensive structured questionnaire that asked about frequency of use of cannabis, of other substances, of methods of use and of positive and negative effects of use. Findings. There were two common types of users; casual users who did not buy cannabis often and regular users who often bought cannabis and used it most days. Fewer users bought cannabis often and used it in a more controlled pattern. The effects of use were similar to those described by Tart [Tart, C. T. (). Marijuana Intoxication: Common Experiences. Nature, 226, 701–704], being predominantly positive and about relaxation and sensuality, although negative effects on mood and cognition were also experienced. Users tended to mix cannabis, tobacco and alcohol more than mixing with other drugs. The biggest health risk posed was tobacco use. Regular users showed more signs of dependence than casual or controlled users. Being in a road traffic accident whilst intoxicated was a strong predictor of other signs of dependence. Signs of dependence did not predict heavy use, which was instead most strongly predicted by seeing cannabis as one of life's main pleasures. Conclusions. Cannabis use has normalised, not all users use in problematic ways and use is moving away from other controlled drugs and towards alcohol and tobacco in a number of respects. There needs to be initiative to dissuade cannabis users from smoking tobacco. As with alcohol, those involved in accidents need to be questioned about their cannabis use and referred to drug services as required. Interventions for heavy cannabis use and dependence should be sensitive to the positive aspects of heavy use.