Some psychological correlates of long-term heavy cannabis users.

Fifty persons who had all been heavy cannabis users for a long time were given psychological tests measuring psychomotor, perceptual and other variables. Half of these persons were "Charas" smokers, half "Bhang" drinkers. The duration of cannabis use was 4--10 years, with an average daily dose of 150 mg tetrahydrocannabinol. A matched control group of twenty-five persons were given the same tests. Compared with this group, the cannabis users were found to react more slowly, to be poorer in concentration and time estimation, to have higher neuroticism and greater perceptuo-motor disturbance. The higher neuroticism and greater perceptuo-motor disturbance. The Charas smokers were the poorest performers and also showed poor memory, lowered psychomotor activity, and poor size estimation.