User reports of problems associated with alcohol and marijuana.

A general population sample of 5126 New Zealanders aged 15-45 in two regions was surveyed to determine their use of alcohol, tobacco, marijuana, and other illicit drugs. Self-reported problems were recorded on identical scales for alcohol and marijuana in order to make a direct comparison between alcohol and marijuana-related problems. The results suggest that alcohol-related problems were more common than marijuana-related ones in the general population, reflecting the fact that alcohol use was more widespread. Within the 17% of the sample who had used both alcohol and marijuana in the last 12 months more problems were reported from alcohol, once again reflecting differences in amounts consumed. Among heavier users of marijuana both alcohol and marijuana-related problems were more commonly reported than in the general sample. Problems were reported at similar levels for both drugs and the pattern of problems is somewhat similar.