Abstract
The amotivational syndrome hypothesis states that marijuana use decreases the users' activity level and will to achieve. The syndrome is a consistent feature of the clinical studies that dominate the marijuana literature, but the experimental studies have produced equivocal results. The present study used an objective measure of motivation to determine the effect of various levels of marijuana usage on motivation. The subjects were 55 high-school age adolescents who were categorized into four marijuana usage groups: non-users, casual users, heavy users, and heavy users who were now ex-users. The results showed that the heavy- and ex-users were significantly lower on the measure of motivation than the casual and non-users. The conclusion was that a third factor, such as boredom or peer-group association, produces both an increased likelihood of heavy marijuana use and lowered motivation.