Social effects of marijuana use in a recreational setting.

Adult male volunteers with a prior history of either moderate (N = 12) or heavy (N = 14) marijuana use were systematically observed before, during, and after a 21-day period of free access to marijuana cigarettes. Data relevant to social interaction and recreational preferences were collected at hourly intervals. Moderate users consumed an average of 2.6 cigarettes per day and showed both acute and persistent (21-day) decrements in social interaction. Heavy users consumed 5.7 cigarettes per day but indicated fewer social reactions. The results suggested that marijuana inhibits social interaction in moderate users but behavioral tolerance in heavy users may mitigate this effect.