Cannabidiol for Treatment of Non-affective Psychosis and Cannabis Use

Cannabidiol for Treatment of Non-affective Psychosis and Cannabis Use

This trial examines the efficacy of cannabidiol (CBD) versus risperidone for treatment of psychosis in patients with non affective-psychosis and lifetime use of cannabis.

People with psychosis and comorbid cannabis use are particularly difficult to treat because cannabis use worsens psychotic symptoms and increases the risk that a first-episode psychosis will progress to schizophrenia. It is the THC (tetrahydrocannabinol) content in cannabis that aggravates psychotic symptoms whereas the CBD content has potential therapeutic effects. This trial investigates treatment with CBD (without THC) versus risperidone (an antipsychotic agent) in people with psychosis and lifetime use of cannabis. We hypothesize that CBD will ameliorate psychotic symptoms and reduce the frequency of cannabis use to a larger extent than risperidone. Sleep disturbances are often a limiting factor in the treatment of psychosis, and it is also examined how CBD affects objective and subjective sleep quality as well as circadian rest-activity cycles. Based on previous studies investigating CBD as monotherapy in patients with schizophrenia, it is expected that CBD will be associated with fewer adverse events than risperidone.

Inclusion criteria:

• ICD-10 diagnosis of schizophrenia (DF20.X), paranoid psychosis (DF22.X), acute/intermittent psychotic disorder (DF23.X), schizoaffective psychosis (DF25.X), other/not specified nonorganic psychotic disorder (DF28/DF29), or cannabis induced psychotic disorder (DF12.5)
• PANSS ≥ 60 and score of ≥ 4 on ≥ 2 PANSS-Positive subscale items: Delusions (P1), conceptual disorganization (P2), hallucinatory behaviour (P3), grandiosity (P5), suspiciousness (P6)
• Lifetime cannabis use
• Age 18-45 years
• Female patients of childbearing potential need to utilize a proper method of contraception

Exclusion criteria:

• Treatment resistance as defined by treatment (ever) with clozapine
• Dependence syndrome of alcohol or psychoactive substances other than cannabis (DF1X.2 other than DF12.2)
• Psychotic disorder induced by alcohol or psychoactive substances other than cannabis (DF1X.5 other than DF12.5)
• Treatment with a long-acting injectable antipsychotic within the past month (or corresponding to the usual interval between two injections)
• Treatment with an oral antipsychotic within the past 7 days
• Use of self-administered CBD products during the trial
• Patients involuntarily admitted
• Pregnancy or lactation
• Severe physical illness that might influence the ability to comply with the protocol