The interaction of ethanol and delta9-tetrahydrocannabinol in man: effects on perceptual, cognitive and motor functions.

Twelve paid student volunteers (8 male, 4 female) were used in a double-blind crossover experiment to investigate the effects of delta9-tetrahydrocannabinol (THC) alone, and in combination with ethanol, on human perceptual, cognitive and motor functions. Both THC (10 mg/70 kg) and ethanol (0-5 g/kg) had little effect when administered alone. The combination of drugs, however, induced a significnat decrement in performance in some of the tests and this interaction was considered to be at least additive. The peak blood ethanol concentration was higher (P = 0-05) when subjects received both ethanol and THC than when they received ethanol alone.