Review Article

Preclinical and Clinical Evidence Supporting Use of Cannabidiol in Psychiatry

Table 3

Clinical studies investigating on CBD anxiolytic effect in healthy subjects.

CBD effectsStudy designPopulationTreatmentEndpointsOutcomeReference

Reduction of delta 9-THC provoked anxietyDouble-blinded, placebo-controlled clinical trialSample: 8 healthy volunteers (six men and two women), aged between 20 and 38 years (average 27)Each volunteer participated in five experimental sessions, separated by a minimum interval of 1 week. Volunteers received orally one of the following treatments: Delta-9-THC 0.5 mg/kg, 1 mg/kg CBD, a mixture containing 0.5 mg/kg delta 9-THC and 1 mg/kg CBD;
10 mg placebo; 10 mg diazepam as control group
Interviews and spontaneous reports, Spielberger’s state- trait anxiety inventory (STAI), Addiction Research Center Inventory for Marihuana Effects (ARCI-Mu), Analogue Self-Rating Scale for Subjective Feelings; Scale of Bodily Symptoms Radial Artery Pulse Rate was used to assess subject’s anxiety stateCBD treatment blocked the anxiety provoked by delta 9-THC
This antagonism does not appear to be caused by a general block of delta 9-THC effects since no change was detected in the pulse-rate measurements
Action of cannabidiol on the anxiety and other effects produced by delta 9-THC in normal subjects; Zuardi et al. [23]

Modulation of delta 9-THC effectsRandomized, double-blind, placebo-controlled clinical trialSample: 40 healthy male volunteers aged between 21 and 34 years8 groups of 5 volunteers each received, respectively, placebo, 30 mg of delta 9-THC, 15, 30, and 60 mg of CBD, and mixtures of 30 mg of delta-9-THC plus either 15, 30, or 60 mg of CBDPulse rate, time production tasks and psychological logical reactions were measured at several time intervals after drug ingestionThe dose of 15–60 mg of CBD alone provoked no effects
CBD blocked most of the effects of delta 9-THC when both drugs were given together
CBD also decreased the anxiety component of Ag-THC effects
Cannabidiol modulates the effects of a 9-tetrahydrocannabinol in man [39]

CBD = cannabidiol; delta-9-THC = delta-9-tetrahydrocannabinol.