title: Towards stage specific treatments: effects of duration of illness on therapeutic response to adjunctive treatment with N-acetyl cysteine in schizophrenia.
abstract: Schizophrenia is a chronic and often debilitating disorder in which stage of illness appears to influence course, outcome, prognosis and treatment response. Current evidence suggests roles for oxidative, neuroinflammatory, neurotrophic, apoptotic, mitochondrial and glutamatergic systems in the disorder; all targets of N-acetyl cysteine (NAC). A double blind, placebo controlled trial suggested NAC to be beneficial to those diagnosed with schizophrenia. The current manuscript aims to investigate duration of the illness as a key factor that may be modulating the response to NAC in the participants who took part in the study. A sample of 121 participants were randomised in a double fashion to 24 weeks (placebo=62; NAC=59). Clinical and functional variables were collected over the treatment period. Duration of the illness at baseline was grouped into <10 years, 10-<20 years and >20 years. Mixed Model Repeated Measures Analysis was used to explore the effect of illness duration on response to treatment with NAC. A significant interaction between duration of the illness and response to treatment with NAC was consistently found for positive symptoms and functional variables, but not for negative or general symptoms or for side effect related outcomes. The pattern of changes suggests that this mediator effect of duration of illness in response to treatment is more evident in those participants with 20 years or more of illness duration. Our results suggest a potential advantage of adjunctive NAC over placebo on functioning and positive symptoms reduction in those patients with chronic schizophrenia. This has potential for suggesting stage specific treatments.
authors.affiliation: Orygen Youth Health Research Centre, Centre for Youth Mental Health, University of Melbourne, Victoria, Australia; Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne and Melbourne Health, 161 Barry Street, Carlton South, Victoria 3053, Australia; Child and Adolescent Psychiatry Department, Hospital General Universitario Gregorio Marañón School of Medicine, Universidad Complutense, IiSGM, CIBERSAM, Madrid, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Rapado-Castro
authors.affiliation: Orygen Youth Health Research Centre, Centre for Youth Mental Health, University of Melbourne, Victoria, Australia; Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne and Melbourne Health, 161 Barry Street, Carlton South, Victoria 3053, Australia; IMPACT Strategic Research Centre, Deakin University, School of Medicine, Barwon Health, P.O. Box 291, Geelong 3220, Australia; Florey Institute for Neuroscience and Mental Health, University of Melbourne, Kenneth Myer Building, 30 Royal Parade, 3052 Parkville, Australia. Electronic address: mikebe@barwonhealth.org.au.
authors.forename: Michael
authors.initials: M
authors.lastname: Berk
authors.affiliation: IMPACT Strategic Research Centre, Deakin University, School of Medicine, Barwon Health, P.O. Box 291, Geelong 3220, Australia.
authors.forename: Kamalesh
authors.initials: K
authors.lastname: Venugopal
authors.affiliation: University of Melbourne, Department of Psychiatry, Level 1 North, Main Block, Royal Melbourne Hospital, Parkville 3052, Australia.
authors.forename: Ashley I
authors.initials: AI
authors.lastname: Bush
authors.affiliation: IMPACT Strategic Research Centre, Deakin University, School of Medicine, Barwon Health, P.O. Box 291, Geelong 3220, Australia.
authors.forename: Seetal
authors.initials: S
authors.lastname: Dodd
authors.affiliation: IMPACT Strategic Research Centre, Deakin University, School of Medicine, Barwon Health, P.O. Box 291, Geelong 3220, Australia; Florey Institute for Neuroscience and Mental Health, University of Melbourne, Kenneth Myer Building, 30 Royal Parade, 3052 Parkville, Australia.
authors.forename: Olivia M
authors.initials: OM
authors.lastname: Dean
mesh_terms: D000111:Acetylcysteine / Q000008:administration & dosage / Q000627:therapeutic use*; D000328:Adult; D014150:Antipsychotic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D008297:Male; D012559:Schizophrenia / Q000188:drug therapy*; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D014150:Antipsychotic Agents; D000111:Acetylcysteine
keywords: Glutathione; N-acetyl cysteine; Neuroprogression; Oxidative stress; Schizophrenia; Staging