Interpersonal effects of marijuana. A model for the study of interpersonal psychopharmacology.

The effect of marijuana on affective changes and interpersonal skills, including empathy, acceptance, warmth, and genuineness, was studied in 20 dyadic relationships in which the experimental subject smoking marijuana containing 6 mg of delta-9-tetrahydrocannabinol and a placebo in separate trials. Marijuana caused a relative decrease in the ratings of the interpersonal skills of the experimental subjects and decreased affective resonance between the experimental subjects and their partners.