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N-acetyl cysteine as a glutathione precursor for schizophrenia--a double-blind, randomized, placebo-controlled trial

journal contribution
posted on 2008-09-01, 00:00 authored by Michael BerkMichael Berk, D Copolov, Olivia DeanOlivia Dean, K Lu, S Jeavons, I Schapkaitz, M Anderson-Hunt, F Judd, F Katz, P Katz, S Ording-Jespersen, J Little, P Conus, M Cuenod, K Q Do, A I Bush
BACKGROUND: Brain glutathione levels are decreased in schizophrenia, a disorder that often is chronic and refractory to treatment. N-acetyl cysteine (NAC) increases brain glutathione in rodents. This study was conducted to evaluate the safety and effectiveness of oral NAC (1 g orally twice daily [b.i.d.]) as an add-on to maintenance medication for the treatment of chronic schizophrenia over a 24-week period. METHODS: A randomized, multicenter, double-blind, placebo-controlled study. The primary readout was change from baseline on the Positive and Negative Symptoms Scale (PANSS) and its components. Secondary readouts included the Clinical Global Impression (CGI) Severity and Improvement scales, as well as general functioning and extrapyramidal rating scales. Changes following a 4-week treatment discontinuation were evaluated. One hundred forty people with chronic schizophrenia on maintenance antipsychotic medication were randomized; 84 completed treatment. RESULTS: Intent-to-treat analysis revealed that subjects treated with NAC improved more than placebo-treated subjects over the study period in PANSS total [-5.97 (-10.44, -1.51), p = .009], PANSS negative [mean difference -1.83 (95% confidence interval: -3.33, -.32), p = .018], and PANSS general [-2.79 (-5.38, -.20), p = .035], CGI-Severity (CGI-S) [-.26 (-.44, -.08), p = .004], and CGI-Improvement (CGI-I) [-.22 (-.41, -.03), p = .025] scores. No significant change on the PANSS positive subscale was seen. N-acetyl cysteine treatment also was associated with an improvement in akathisia (p = .022). Effect sizes at end point were consistent with moderate benefits. CONCLUSIONS: These data suggest that adjunctive NAC has potential as a safe and moderately effective augmentation strategy for chronic schizophrenia.

History

Journal

Biological Psychiatry

Volume

64

Issue

5

Pagination

361 - 368

Publisher

Elsevier

Location

Philadelphia, Pa.

ISSN

0006-3223

eISSN

1873-2402

Language

eng

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

2008, Society of Biological Psychiatry