The effect of cannabidiol, alone and in combination with ethanol, on human performance.

Fifteen volunteers received cannabidiol (CBD) (320 microgram/kg) or placebo (both orally, T0), and 60 min later they consumed an ethanolic beverage (0.54 g/kg) or placebo. The effects were measured at T1 (100 min after CBD ingestion), T2 (160 min) and T3 (220 min) using cognitive, perceptual and motor function tests. Factorial analysis indicated that test procedures could be adequately expressed by three rotated factors: A reaction speed factor (I), a standing steadiness factor (II) and a psychomotor coordination/cognitive factor (III). Ethanol produced a significant decrement in factor III. There was no demonstrable effect of CBD, either alone or in combination with ethanol. Neither CBD nor ethanol produced any significant effect on pulse rate. Prior administration of CBD did not significantly affect the blood ethanol levels. Whilst the subjects were able to identify correctly when they were given ethanol, they did not report any subjective effects of CBD.