Acute Psychotropic Effects of Oral Cannabis Extract with a Defined Content of Δ9-Tetrahydrocannabinol (THC) in Healthy Volunteers

Introduction: The medical use of cannabinoids is limited mainly by their undesirable effects. With respect to acute psychotropic effects, the aim of this study is the comparison of an oral cannabis extract and low-dose diazepam in a cross-over experiment in drug-nave healthy women. Methods: Sixteen healthy females participated in this randomized, double-blind, active comparator-controlled, single-dose, balanced 2-way cross-over study. Cannabis extract with standardised Delta(9)-tetrahydrocannabinol (THC) content (20 mg) or active placebo (5 mg diazepam) was administered orally. Subjects were assessed by self- and observer-rated visual analogue scales (VAS), the brief psychiatric rating scale (BPRS) and three psychomotor tests up to 6 h after administration. Results: VAS showed significantly elevated fatigue, drowsiness, dizziness, and "feeling high " after cannabis as compared to baseline and diazepam. BPRS scores were significantly higher after cannabis intake. Only in one psychomotor test a decrease of psychomotor activity after cannabis was evident. One subject in the cannabis condition experienced severe transient psychotic symptoms. Discussion: Orally administered cannabis produced significant central depressant side-effects compared to diazepam, mostly subjective effects (VAS) but marginal effects in psychomotor performance in 15 healthy females. Regarding the medical use of cannabis, a rigorous benefit-risk analysis and an exact psychiatric assessment before and during treatment are necessary.