EFFECTS OF MARIJUANA ON PERFORMANCE OF A COMPUTERIZED COGNITIVE-NEUROMOTOR TEST BATTERY

To evaluate the sensitivity of a computerized cognitive-neuromotor tes t battery in assessing the effects of marijuana (Delta-9-tetrahydrocan nabinol [THC]), we conducted a study of 10 healthy male volunteers who were experienced marijuana smokers. After extensive training on the p erformance tasks, each subject was tested on three separate days after smoking a cigarette containing either 1.75% THC, 3.55% THC, or placeb o according to a randomized double-blind repeated measures design. Tes ting was carried out before smoking and 30, 90, and 150 minutes after smoking the cigarette. Of the five tasks employed, the digit-symbol su bstitution test with memory and the reaction time task were the measur es most sensitive to effects of marijuana. We examined the usefulness of the coefficient of variation and effect size as indices of sensitiv ity to be used across different types of tasks.