Cannabidiol for Treatment of Non-affective Psychosis and Cannabis Use

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