Cannabis use and callosal white matter structure and integrity in recent-onset schizophrenia.

Adolescent-onset cannabis use, compared with adult-onset use, has been associated with a higher risk for developing symptoms of schizophrenia-like psychotic disorders. To test the hypothesis that onset of cannabis use in early adolescence in male schizophrenia patients is associated with abnormalities in white matter structure and integrity, we used high resolution structural and diffusion tensor brain images to compare three groups of patients: those who started regular use of cannabis (1) before the age of 15 years (early-onset cannabis users, n = 10) or (2) at the age of 17 years or later (late-onset cannabis users, n = 8), and (3) those who were cannabis naïve (n = 8). To verify patient findings, we also compared white matter integrity of the three patient groups with that of a healthy control group (n = 10).

Reasons for cannabis use and effects of cannabis use as reported by patients with psychotic disorders.

Background: Cannabis is one of the most commonly used substances in patients with a psychotic disorder and is associated with a higher risk of psychotic relapses. Identifying reasons for cannabis use and subjective effects in patients with psychotic disorders can provide insight into the functions of cannabis use, and this may lead to targeted interventions.

Methods: A literature search of the PubMed and PsycINFO databases for articles published from 1985 till 2008 was carried out to review studies that examined self-reported reasons for cannabis use and self-reported effects of cannabis use in patients with psychotic disorders.

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

Background: 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.