The object of the experiment was to verify whether cannabidiol (CBD) reduces the anxiety provoked by d9-THC in normal volunteers, and whether this effect occurs by a general block of the action of d9-THC or by a specific anxiolytic effect. Appropriate measurements and scales were utilized and the eight volunteers received, the following treatments in a double-blind procedure : 0.5 mg/kg d9-THC, 1 mg/kg CBD, a mixture containing 0.5 mg/kg d9-THC and 1 mg/kg CBD, and placebo and diazepam (10 mg) as controls. Each volunteer received the treatments in a different sequence. It was verified that CBD blocks the anxiety provoked by d9-THC, however...