Cannabidiol (CBD) has been found to have a range of potential therapeutic benefits, including the relief of anxiety and the reduction of psychotic symptoms. Recent studies have explored the effect of CBD on people at high risk of developing psychosis, and have provided important information about the areas of the brain that CBD is targeting. In a 6-week double-blind parallel group randomized controlled trial (RCT) of 300 mg of CBD twice daily, researchers found that CBD improved overall scores on the Unified Parkinson's Disease Classification Scale and did not worsen cognition or motor function. Surprisingly, in addition to relieving anxiety, CBD reduced psychotic symptoms commonly induced by tetrahydrocannabinol (THC).
In two other RCTs, CBD was administered as an adjunctive treatment for 6 weeks with a placebo control; however, the results were contradictory. In one study, the placebo and 300 mg CBD groups improved performance in the second session compared to the first, while the 600 mg CBD group did not. A recent study explored the effect of CBD and placebo on people who had not received previous treatment and were at high risk of developing psychosis. The brains of these individuals were scanned during a verbal learning task, and it was found that when they were given a dose of CBD, the activation in certain areas of the brain became more similar to the activation seen in people without psychosis during the same tasks.
Joseph Pierre, MD, a psychiatrist and professor at the University of California at Los Angeles, suggests that CBD's potential role in treating schizophrenia begins with THC. Studies have shown that another important cannabinoid found in cannabis, cannabidiol (CBD), may be a possible alternative or complementary treatment for psychosis and schizophrenia. Taken together, these studies provide some evidence that pure CBD may have beneficial effects in the treatment of CUD in the general population of patients with CUD. However, this review is limited by the small number of controlled studies available on the subject, and further research is needed to fully understand how CBD can be used to treat psychosis.