Exploring the Relationship Between Cannabidiol and Psychosis – Psychiatric Times


The association between Cannabis sativa (cannabis) and psychosis goes back at least as far as the Pen-ts’ao Ching, the world’s oldest pharmacopeia, which is attributed to the Chinese emperor Shen-Nung (circa 2700 BC). It says, “ma-fen [the fruit of cannabis] if taken in excess will produce visions of devils . . . over the long term, it makes one communicate with spirits.”1 In the West, cannabis was used as an experimental psychotomimetic in the 19th century by pioneering French psychiatrist Jacques-Joseph Moreau, and it continues to be used to this day.1,2 Cannabis’ acute psychotomimetic effect is transitory; however, consistent evidence indicates that the chronic and intense use of the plant, especially if started in adolescence, contributes to the occurrence of schizophrenia.3

We know that cannabis contains about 100 cannabinoid compounds and that the psychotomimetic effects of the plant are induced by tetrahydrocannabinol (THC).4 However, we have also known since the early 1970s that the effects of cannabis cannot be attributed solely to THC.5 Other cannabinoids, including cannabidiol (CBD), have intrinsic actions as well.6

Antipsychotic properties

In 1982, a study of the interactions between THC and CBD in healthy volunteers provided the first evidence that CBD might have antipsychotic properties. Our group administered oral CBD concomitantly with a high dose of THC to investigate whether CBD could attenuate THC-induced anxiety. Surprisingly, in addition to alleviating anxiety, CBD reduced the psychotic symptoms commonly induced by THC.7

More recently, this observation was confirmed in a study with THC administrated intravenously after