title: Nitric oxide in patients with schizophrenia: the relationship with the severity of illness and the antipsychotic treatment.
abstract: OBJECTIVE
  Past studies regarding the relationship between nitric oxide and schizophrenia have reported controversial results. Consequently, the aims of this study are i) to analyze the differences in nitric oxide concentration between patients with schizophrenia and healthy controls, ii) to investigate the influence of antipsychotic treatment on nitric oxide, iii) to correlate nitric oxide concentration with severity of illness, and iv) to investigate the relationship between nitric oxide and any personality disorder.
  
  
  METHODS
  We recruited 24 patients and 24 controls; the sample was divided into three groups of 8 patients, each according to the pharmacological treatment (haloperidol, olanzapine, or risperidone). The severity of illness was assessed by PANSS and personality traits were evaluated by SCID II. A blood sample was taken to assess the plasma concentration of nitrites and nitrates.
  
  
  RESULTS
  Patients presented higher nitrate levels than controls (p < 0.05); subjects under olanzapine reported lower nitrate levels than those treated with risperidone (p < 0.05) or haloperidol (p < 0.001). Nitrate levels were correlated with PANSS total score (rho = 0.748; p < 0.001), but not with SCID II scores.
  
  
  CONCLUSIONS
  Despite the fact that this study found a correlation between PANSS score and nitrate levels, it is unclear whether nitric oxide is related to the severity of schizophrenia, because nitrate levels are also affected by antipsychotic treatment.
authors.affiliation: Department of Psychiatry, Policlinico-Vittorio Emanuele Hospital, University of Catania, Via Santa Sofia 78, 95100, Catania, Italy. giuseppeminutolo@hotmail.com
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Minutolo
authors.forename: Antonino
authors.initials: A
authors.lastname: Petralia
authors.forename: Salvatore
authors.initials: S
authors.lastname: Dipasquale
authors.forename: Eugenio
authors.initials: E
authors.lastname: Aguglia
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D001569:Benzodiazepines / Q000627:therapeutic use; D016022:Case-Control Studies; D005260:Female; D006220:Haloperidol / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D009566:Nitrates / Q000097:blood; D009569:Nitric Oxide / Q000097:blood; D000077152:Olanzapine; D011569:Psychiatric Status Rating Scales; D018967:Risperidone / Q000627:therapeutic use; D012559:Schizophrenia / Q000097:blood* / Q000188:drug therapy / Q000503:physiopathology; D012720:Severity of Illness Index; D055815:Young Adult
chemical_list: D014150:Antipsychotic Agents; D009566:Nitrates; D001569:Benzodiazepines; D009569:Nitric Oxide; D006220:Haloperidol; D018967:Risperidone; D000077152:Olanzapine