Marihuana effects on TAT form and content.

In a double-blind study, 72 normal male subjects were given either placebo or marihuana containing 20 mg. Delta-9-tetrahydrocannabinol. Stories written to cards selected from the Thematic Apperception Test did not differ on hostile or sexual content scales between drug and placebo conditions, but 6 out of 10 scales specifically constructed to detect marihuana effects were successful at differentiating the two conditions. Under marihuana the stories had a timeless, non-narrative quality, with greater discontinuity in thought sequence and more frequent inclusion of contradictory ideas. Novelty of content was somewhat increased by marihuana, while relation to the picture, imagery, repetition, and closure were not significantly affected.