Cessation of cannabis use by patients with recent-onset schizophrenia and related disorders

Cannabis abuse has been found to be a component risk factor for the onset and poor outcome during the early course of schizophrenia and related disorders. Cannabis use has become a target for prevention and treatment of schizophrenia patients. Therefore, knowledge of factors that influence continuation and cessation of cannabis use is crucial. However, little is known about factors associated with cessation of cannabis use in young schizophrenia patients.

We examined medical records of 206 consecutively admitted young patients with schizophrenia or related disorders, to explore factors associated with cessation of cannabis use.

Of all patients that had used cannabis (167) in the past, more than half (87) ceased the use of cannabis before they were admitted to our clinic. Most patients ceased the use of cannabis after they became psychotic and after their first contact with psychiatric services. According to the urinalysis, only five patients seemed to have lied about their time of cessation. No differences in patient characteristics were found between patients that ceased their use of cannabis and patients that continued their use.

The results suggest that the start of treatment for psychosis is related to the cessation of cannabis use, at least in part of the patients.