title: L-lysine as an adjunct to risperidone in patients with chronic schizophrenia: a double-blind, placebo-controlled, randomized trial.
abstract: Increasing evidence suggest that the nitric oxide signaling system of the brain may contribute to the pathophysiology of schizophrenia, making this system a target for development of novel therapeutics. The objective of this study was to investigate the efficacy and safety of L-lysine as an adjunctive to risperidone in the treatment of patients with chronic schizophrenia during an 8-week trial. Seventy-two chronic schizophrenia inpatients with a Positive and Negative Syndrome Scale (PANSS) total score of ≥ 60 participated in a randomized, double-blind, placebo-controlled trial in the active phase of their disease and underwent 8 weeks of treatment with either L-lysine (6 g/day) or placebo as an adjunctive to risperidone. Patients were evaluated using PANSS and its subscales at baseline and weeks 2, 4, 6 and 8. The primary outcome measure was to evaluate the efficacy of L-lysine in improving schizophrenia symptoms. Repeated measures analysis demonstrated significant effect for time × treatment interaction on the PANSS total (P < 0.001), negative (P < 0.001) and general psychopathology (P < 0.001) subscale scores but not the PANSS positive subscale scores (P = 0.61). The frequency of adverse events (AEs) did not differ significantly between the two treatment groups and no serious AE was observed. The present study demonstrated that l-lysine can be a tolerable and efficacious adjunctive therapy for improving negative and general psychopathology symptoms in chronic schizophrenia. However, the safety and efficacy of higher doses of l-lysine and longer treatment periods still remain unknown.
  
  
  BACKGROUND
  Iranian registry of clinical trials (www.irct.ir): IRCT201202201556N33.
authors.affiliation: Psychiatric Research Center, Roozbeh Hospital, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Atefeh
authors.initials: A
authors.lastname: Zeinoddini
authors.affiliation: Psychiatric Research Center, Roozbeh Hospital, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Morvarid
authors.initials: M
authors.lastname: Ahadi
authors.affiliation: Psychiatric Research Center, Roozbeh Hospital, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Farokhnia
authors.affiliation: Department of Psychiatry, Kurdistan University of Medical Sciences, Sanandaj, Iran.
authors.forename: Farzin
authors.initials: F
authors.lastname: Rezaei
authors.affiliation: Department of Medical Genetics, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mina
authors.initials: M
authors.lastname: Tabrizi
authors.affiliation: Psychiatric Research Center, Roozbeh Hospital, Tehran University of Medical Sciences, Tehran, Iran. Electronic address: s.akhond@neda.net.
authors.forename: Shahin
authors.initials: S
authors.lastname: Akhondzadeh
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D055815:Young Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use; D002908:Chronic Disease; D003863:Depression / Q000188:drug therapy / Q000209:etiology; D004311:Double-Blind Method; D005500:Follow-Up Studies; D008239:Lysine / Q000627:therapeutic use; D011569:Psychiatric Status Rating Scales; D018967:Risperidone / Q000627:therapeutic use; D012559:Schizophrenia / Q000150:complications / Q000188:drug therapy; D016896:Treatment Outcome
chemical_list: D014150:Antipsychotic Agents; D008239:Lysine; D018967:Risperidone
keywords: Clinical trial; Nitric oxide; PANSS; Schizophrenia; l-lysine