A community survey of adverse effects of cannabis use.

This survey estimates the frequency of various adverse effects of the use of the drug cannabis. A sample of 1000 New Zealanders aged 18-35 years were asked to complete a self-administered questionnaire on cannabis use and associated problems. The questionnaire was derived from criteria for the identification of cannabis abuse which are analagous to criteria commonly used to diagnose alcoholism. Of those who responded 38% admitted to having used cannabis. The most common physical or mental health problems, experienced by 22% of users were acute anxiety or panic attacks following cannabis use. Fifteen percent reported psychotic symptoms following use. Problems related to physical and mental health and control of level of intake were more common than social or relationship problems.