In this 2012 double-blind, randomized clinical trial, researchers investigated whether cannabidiol (CBD) could be a viable natural treatment option for acute schizophrenia, comparing its effectiveness with that of the dopamine D2/D3-receptor antagonist amisulpride, one of the most commonly used antipsychotic drugs. The study found CBD to be as effective as amisulpride in improving psychotic symptoms with no relevant difference between the two treatments. CBD also exhibited fewer side effects, including fewer extrapyramidal symptoms, less weight gain, and lower prolactin increase, making it a potentially safer and more tolerable option for schizophrenia patients.
The clinical trial involved 42 patients with acute schizophrenia and showed that both treatments led to significant clinical improvement, as assessed by the reduction in PANSS total score and all subcategories of symptoms of schizophrenia.
The 42 patients were hospitalized for the duration of the study and were randomly assigned to receive either CBD or amisulpride. The dose of each treatment started at 200mg per day and was increased to a daily dose of 200mg four times daily (total 800mg per day) within the first week. The respective treatment was maintained for another 3 weeks. A reduction of each treatment to 600mg per day was allowed for clinical reasons, such as unwanted side effects after week 2. In addition, lorazepam co-medication was allowed with up to 7.5mg per day during the entire study.
The use of antipsychotic drugs in the treatment of schizophrenia often results in side effects such as motor disturbances, weight gain, and sexual dysfunction, which can impact treatment adherence. However, compared to amisulpride, a commonly used antipsychotic drug, the use of CBD was found to result in fewer extrapyramidal symptoms, less weight gain, and lower prolactin increase, which is a predictor of sexual dysfunction. These findings suggest that CBD may be a well-tolerated alternative treatment option for schizophrenia with fewer side effects. Additionally, they found no significant adverse effects of CBD on hepatic or cardiac functions.
The study found that the antipsychotic effects of CBD may be mediated via the endocannabinoid system, through its ability to enhance the endocannabinoid anandamide's signaling by inhibiting the activity of fatty acid amide hydrolase (FAAH), an enzyme responsible for the degradation of anandamide. This hypothesis was supported by the significant association observed in CBD-treated patients between improvement of clinical symptoms and serum anandamide levels, suggesting that the ability of CBD to inhibit FAAH activity and enhance intrinsic anandamide signaling might be a functionally relevant component of its antipsychotic properties.
Overall, the study provides evidence that CBD exerts clinically relevant antipsychotic effects that are associated with marked tolerability and safety, when compared with current conventional medications. The findings suggest a promising therapeutic potential for CBD in the treatment of acute schizophrenia, which warrants further investigation.
Study Title: Cannabidiol enhances anandamide signaling and alleviates psychotic symptoms of schizophrenia
Study Link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3316151