title: Substance abuse and psychosis. The strange case of opioids.
abstract: BACKGROUND
  Psychoses correlated with substance abuse prove to be more common in cases involving cannabinoids, stimulants, hallucinogens, alcohol and polyabuse. Among substance abusers, it has not been ascertained whether opioids have a psychotic effect.
  
  
  OBJECTIVE
  The aim of this review is to investigate whether, among substances of abuse, a distinction can be drawn between pro-psychotic and anti-psychotic agents on the basis of the relationship between these substances and psychosis.
  
  
  METHODS
  Studies were identified by searching through multiple literature databases, including PubMed, Scopus, Web of Knowledge. Hand searches through reference lists of relevant reviews were used to complement the computer searches.
  
  
  RESULTS
  Looking at the relationships linking substances of abuse with psychosis, a distinction can, in fact, be drawn between pro-psychotic and anti-psychotic substances. Even if there are no differences in the addictive processes involved, opiates are the only sedative drugs that possess an anti-psychotic effect.
  
  
  CONCLUSIONS
  The whole topic of opiate agonism merits is due for reconsideration: it is not only the anticraving action of opiate agonism, but also its effectiveness on the psychopathological level that qualifies it as to be viewed as a powerful tool in treating mental illness.
authors.affiliation: Vincent P. Dole Dual Diagnosis Unit, Santa Chiara University Hospital, Department of Neurosciences, University of Pisa, Italy. maremman@med.unipi.it  
authors.forename: A G I
authors.initials: AG
authors.lastname: Maremmani
authors.forename: L
authors.initials: L
authors.lastname: Rovai
authors.forename: F
authors.initials: F
authors.lastname: Rugani
authors.forename: S
authors.initials: S
authors.lastname: Bacciardi
authors.forename: L
authors.initials: L
authors.lastname: Dell'Osso
authors.forename: I
authors.initials: I
authors.lastname: Maremmani
mesh_terms: D000701:Analgesics, Opioid / Q000627:therapeutic use; D014150:Antipsychotic Agents / Q000627:therapeutic use; D017831:Diagnosis, Dual (Psychiatry); D005260:Female; D006801:Humans; D013287:Illicit Drugs / Q000009:adverse effects*; D008297:Male; D011605:Psychoses, Substance-Induced / Q000188:drug therapy / Q000209:etiology; D012737:Sex Factors; D013375:Substance Withdrawal Syndrome / Q000188:drug therapy / Q000209:etiology
chemical_list: D000701:Analgesics, Opioid; D014150:Antipsychotic Agents; D013287:Illicit Drugs