cbd treatment for schizophrenia

Antipsychotic medication is the most important component in the treatment of first-episode psychosis. In the short term, it is used to control the acute presenting symptoms (Huhn et al. 2019). Once these have remitted, continuing with treatment reduces the risk of subsequent relapse (Kishi et al. 2019). In about two-thirds of first-episode patients, the response to treatment of their presenting symptoms is good (Boter et al. 2009) and requires relatively low doses of antipsychotic medication. However, in about a third, these drugs are less effective. In addition, the beneficial effects of these drugs are mainly limited to positive psychotic symptoms; they have less impact on cognitive impairments or negative symptoms (Keefe et al. 2007; Krause et al. 2018). A further issue is that patients with psychosis are often reluctant to take antipsychotic medications, because of their reputation for side effects (Sendt et al. 2015) and because they are associated with schizophrenia, which is perceived as stigmatising (Yılmaz and Okanlı 2015). This reluctance is particularly evident in first-episode patients after their initial symptoms have resolved, as the benefits of prophylactic treatment may not be clear until after a relapse has occurred.


Muller C, Lynch DL, Hurst DP, Reggio PH (2020) A closer look at anandamide interaction with TRPV1. Front Mol Biosci 7:144. https://doi.org/10.3389/fmolb.2020.00144

Corresponding author

Jackson HJ, McGorry PD, Dudgeon P (1995) Prodromal symptoms of schizophrenia in first-episode psychosis: prevalence and specificity. Compr Psychiatry 36:241–250. https://doi.org/10.1016/S0010-440X(95)90068-3

8. Zuardi AW, Morais SL, Guimaraes FS, Mechoulam R. Antipsychotic effect of cannabidiol. J Clin Psychiatry. 1995;56:485-486.

The FDA has recently approved the first cannabis plant-derived medication, Epidiolex (an oral solution of pure CBD), for treatment of seizures associated with Lennox-Gastaut syndrome and Dravet syndrome in patients aged 2 years and older. 1 Consequently, DEA scheduled Epidiolex in Schedule V of the Controlled Substances Act (CSA), the least restrictive schedule. 2 Though Epidiolex is only approved for the above rare seizure disorders, physicians may recommend it off-label for other conditions, based on their own judgment. It is important to note, however, that the only approved form of CBD is Epidiolex and off-label recommendation of other forms of CBD does not follow the same rules.

10. Zuardi AW, Cripp JA, Hallak JE, et al. Cannabidiol for the treatment of psychosis in Parkinson disease. J Psychopharmacol. 2009;23:979-983.

7. Bhattacha ryya S, Morrison PD, Fusar-Poli P, et al. Opposite effects of delta-9-tetrahydrocannabinol and cannabidiol on human brain function and psychopathology. Neuropsychopharmacology. 2010;35:764-774.


2. US Drug Enforcement Administration. FDA-Approved Drug Epidiolex Placed in Schedule V of Controlled Substance Act. 2018. https://www.dea.gov/press-releases/2018/09/27/fda-approved-drug-epidiolex-placed-schedule-v-controlled-substance-act. Accessed February 7, 2019.

9. Zuardi AW, Hallak JE, Dursun SM, et al. Cannabidiol monotherapy for treatment-resistant schizophrenia. J Psychopharmacol. 2006;20:683-686.

Compared with the placebo group, the CBD group showed greater improvement of positive psychotic symptoms over the course of the treatment. Mean improvement of PANSS positive score was 3.2 (SD 2.60) in the CBD group compared with 1.7 (SD 2.76) in the placebo group. Moreover, by the end of the treatment, more patients in the CBD group were rated as “improved” on the CGI-I scale compared with those in the placebo group (78.6% and 54.6%, respectively). Patients who received CBD also showed a trend-level improvement in their cognitive functioning, and a significant improvement of their motor speed compared with controls.


The potential beneficial effects of CBD on cognition in patients with schizophrenia have critical importance, since cognitive deficits are common in schizophrenia (up to 75%-85% of patients), usually precede other symptoms, and respond minimally to the available pharmacological treatments.

The evidence for cannabidiol