title: Correlation of adenosinergic activity with superior efficacy of clozapine for treatment of chronic schizophrenia: a double blind randomised trial.
abstract: OBJECTIVE
  It has been proposed that a deficit of adenosinergic activity could contribute to the pathophysiology of schizophrenia. The authors undertook this study to further evaluate the level of adenosine deaminase (ADA) in patients with chronic schizophrenia treated with monotherapy of haloperidol, risperidone or clozapine and correlation between the ADA level with response to treatment.
  
  
  METHODS
  The trial was a prospective, 8-week, double blind study of parallel groups of patients with chronic schizophrenia. Eligible participants in the study were 51 patients with chronic schizophrenia with ages ranging from 20 to 45 years. All participants were inpatients, in the active phase of illness, and met DSM-IV-TR criteria for schizophrenia. Patients were randomly allocated (17 patients in each group) to risperidone (6 mg/day) or haloperidol 15 mg/day or clozapine (300 mg/day). Serum ADA activity was measured at baseline and week 8.
  
  
  RESULTS
  The plasma levels of ADA in patients with chronic schizophrenia who received clozapine were significantly higher than patients who received haloperidol. In addition, response to treatment was positively correlated with plasma levels of ADA only in the clozapine group (r = 0.46 and p = 0.04).
  
  
  CONCLUSIONS
  The results indicate an increased activity of the enzyme ADA in the serum of schizophrenic patients being treated with clozapine and this increase may be correlated with clozapine's superior antipsychotic efficacy.
authors.affiliation: Research Center for Behavioral Disorders and Substance Abuse, Hamadan University of Medical Sciences, Hamadan, Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Ghaleiha
authors.forename: Navid
authors.initials: N
authors.lastname: Honarbakhsh
authors.forename: Mohammad-Ali
authors.initials: MA
authors.lastname: Boroumand
authors.forename: Morteza
authors.initials: M
authors.lastname: Jafarinia
authors.forename: Mina
authors.initials: M
authors.lastname: Tabrizi
authors.forename: Farzin
authors.initials: F
authors.lastname: Rezaei
authors.forename: Maedeh
authors.initials: M
authors.lastname: Raznahan
authors.forename: Shahin
authors.initials: S
authors.lastname: Akhondzadeh
mesh_terms: D000241:Adenosine / Q000097:blood; D000243:Adenosine Deaminase / Q000097:blood*; D000328:Adult; D002908:Chronic Disease; D003024:Clozapine / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D006220:Haloperidol / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D018967:Risperidone / Q000627:therapeutic use; D012559:Schizophrenia / Q000097:blood* / Q000188:drug therapy*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000243:Adenosine Deaminase; D003024:Clozapine; D006220:Haloperidol; D000241:Adenosine; D018967:Risperidone