title: Cannabis and schizophrenia.
abstract: BACKGROUND
  Many people with schizophrenia smoke cannabis, and it is unclear why a large proportion do so and if the effects are harmful or beneficial. It is also unclear what the best method is to allow people with schizophrenia to alter their cannabis intake.
  
  
  OBJECTIVE
  To assess the effects of specific psychological treatments for cannabis reduction in people with schizophrenia. To assess the effects of antipsychotics for cannabis reduction in people with schizophrenia. To assess the effects of cannabinoids (cannabis-related chemical compounds derived from cannabis or manufactured) for symptom reduction in people with schizophrenia.
  
  
  METHODS
  We searched the Cochrane Schizophrenia Group Trials Register (August 2013) and all references of articles selected for further relevant trials. We contacted the first author of included studies for unpublished trials or data.
  
  
  METHODS
  We included all randomized controlled trials involving cannabinoids and schizophrenia/schizophrenia-like illnesses, which assessed: (1) treatments to reduce cannabis use in people with schizophrenia and (2) the effects of cannabinoids on people with schizophrenia.
  
  
  CONCLUSIONS
  Results are limited and inconclusive due to the small number and size of randomized controlled trials available and quality of data reporting within these trials. Currently, there is no evidence to demonstrate that one type of adjunct psychological therapy or one type of drug therapy is more effective than another. There is also insufficient evidence to show that cannabidiol has an antipsychotic effect.
authors.affiliation: Queens Medical Centre, School of Medicine, The University of Nottingham, Nottinghamshire, UK; Pushpa-Rajah and Benjamin Mcloughin were co-lead authors. mzyjp3@nottingham.ac.uk.
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Pushpa-Rajah
authors.affiliation: Queens Medical Centre, School of Medicine, The University of Nottingham, Nottinghamshire, UK; Pushpa-Rajah and Benjamin Mcloughin were co-lead authors.
authors.forename: Benjamin C
authors.initials: BC
authors.lastname: McLoughlin
authors.affiliation: Western Sydney Local Health District-Mental Health, Parramatta, Australia;
authors.forename: Donna
authors.initials: D
authors.lastname: Gillies
authors.affiliation: Faculty of Health Sciences and Medicine, Bond University, Gold Coast, Australia;
authors.forename: John
authors.initials: J
authors.lastname: Rathbone
authors.affiliation: Becklin Centre, CRHT, Leeds, UK;
authors.forename: Hannele
authors.initials: H
authors.lastname: Variend
authors.affiliation: Department of Medicine, University of Nottingham, Nottingham, UK;
authors.forename: Eliana
authors.initials: E
authors.lastname: Kalakouti
authors.affiliation: Department of Medicine, University of Nottingham, Nottingham, UK;
authors.forename: Katerina
authors.initials: K
authors.lastname: Kyprianou
mesh_terms: D002186:Cannabinoids / Q000494:pharmacology*; D015897:Comorbidity; D006801:Humans; D002189:Marijuana Abuse / Q000188:drug therapy / Q000453:epidemiology / Q000628:therapy*; D012559:Schizophrenia / Q000453:epidemiology
chemical_list: D002186:Cannabinoids