Marijuana: dose-response effects on pulse rate, subjective estimates of potency, pleasantness, and recognition memory.

34 experienced marijuana users were divided into four equated groups of eight subjects each based on recognition memory test performance. One week later each group was retested following administration of marijuana containing 0, 5, 10 or 15 mg delta9-tetrahydrocannabinol. A dose-related effect of marijuana on pulse rate and subjective measures of potency and pleasantness occurred. Ratings of potency and changes in pulse rate were highly correlated, but this relationship did not hold within a given dosage group as determined by partial correlations. No effect of marijuana on the distribution of hit and false alarm rates or confidence ratings during the recognition memory test was noted.