COMPARATIVE EFFECTS OF ALCOHOL AND MARIJUANA ON MOOD, MEMORY, AND PERFORMANCE

This study compared subjective and behavioral effect profiles of alcoh ol and smoked marijuana using technology that controlled puffing and i nhalation parameters. Male volunteers (n = 5) with histories of modera te alcohol and marijuana use were administered three doses of alcohol (0.25, 0.5, or 1.0 g/kg), three doses of marijuana [4, 8, or 16 puffs of 3.55% Delta(9)-tetrahydrocannabinol (THC)], and placebo in random o rder under double blind conditions in seven separate sessions. Blood a lcohol concentration (10-90 mg/dl) and THC levels (63-188 ng/ml) indic ated that active drug was delivered to subjects dose dependently. Alco hol and marijuana produced dose-related changes in subjective measures of drug effect. Ratings of perceived impairment were identical for th e high doses of alcohol and marijuana. Both drugs produced comparable impairment in digit-symbol substitution and word recall tests, but had no effect in time perception and reaction time tests. Alcohol, but no t marijuana, slightly impaired performance in a number recognition tes t. These data are useful for understanding the relative performance im pairment produced by alcohol and marijuana at the delivered doses and the relationship between their subjective and behavioral effects. (C) 1997 Elsevier Science Inc.