title: Relationship between cannabis and psychosis: Reasons for use and associated clinical variables.
abstract: The mechanism underneath the relationship between cannabis and psychosis remains controversial, for which several hypotheses have been proposed, including cannabis as self-medication and cannabis as a risk for the development of psychosis. The aim of this work was to study the relationship between cannabis and psychosis in first-episode psychosis cannabis users and non-users, and non-psychotic cannabis users. The age at the first psychotic episode, duration of untreated psychosis, psychopathology and reasons for cannabis use were assessed. First-episode psychosis cannabis users showed an earlier age at psychosis onset than non-user patients. No significant differences in symptomatology were found. The distinguishing reasons to use cannabis for patients with first-episode psychosis with respect to non-psychotic users were to arrange their thoughts and deal with hallucinations and suspiciousness. These findings are in agreement with both hypotheses: self-medication and secondary psychosis hypothesis. However, longitudinal prospective cohort studies assessing reasons for cannabis use are needed to investigate both hypotheses and their complementarity.
authors.affiliation: IMIM (Hospital del Mar Medical Research Institute) - Neurosciences, Psychiatry, Barcelona, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Spain. Electronic address: manesantacana@yahoo.es.
authors.forename: Anna
authors.initials: A
authors.lastname: Mané
authors.affiliation: Universitat Pompeu Fabra and Universitat Autònoma Barcelona, Barcelona, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Fernández-Expósito
authors.affiliation: IMIM (Hospital del Mar Medical Research Institute) - Neurosciences, Psychiatry, Barcelona, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Spain.
authors.forename: Daniel
authors.initials: D
authors.lastname: Bergé
authors.affiliation: IMIM (Hospital del Mar Medical Research Institute) - Neurosciences, Psychiatry, Barcelona, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Gómez-Pérez
authors.affiliation: IMIM (Hospital del Mar Medical Research Institute) - Neurosciences, Psychiatry, Barcelona, Spain.
authors.forename: Agnés
authors.initials: A
authors.lastname: Sabaté
authors.affiliation: IMIM (Hospital del Mar Medical Research Institute) - Neurosciences, Psychiatry, Barcelona, Spain.
authors.forename: Alba
authors.initials: A
authors.lastname: Toll
authors.affiliation: IMIM (Hospital del Mar Medical Research Institute) - Neurosciences, Psychiatry, Barcelona, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Diaz
authors.affiliation: IMIM (Hospital del Mar Medical Research Institute) - Neurosciences, Psychiatry, Barcelona, Spain.
authors.forename: Cristobal
authors.initials: C
authors.lastname: Diez-Aja
authors.affiliation: IMIM (Hospital del Mar Medical Research Institute) - Neurosciences, Psychiatry, Barcelona, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Spain.
authors.forename: Victor
authors.initials: V
authors.lastname: Perez
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D002188:Cannabis / Q000009:adverse effects*; D003430:Cross-Sectional Studies; D005260:Female; D006212:Hallucinations / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D006801:Humans; D008297:Male; D002189:Marijuana Abuse / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology*; D011446:Prospective Studies; D011599:Psychopathology; D011618:Psychotic Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology*; D012307:Risk Factors; D012559:Schizophrenia / Q000175:diagnosis / Q000453:epidemiology*; D012565:Schizophrenic Psychology; D012651:Self Medication / Q000523:psychology*; D011795:Surveys and Questionnaires; D055815:Young Adult
keywords: Cannabis; First-episode; Reasons for use; Schizophrenia; Self-medication