N-acetyl cysteine (NAC) augmentation in the treatment of obsessive-compulsive disorder: A phase III, 20-week, double-blind, randomized, placebo-controlled trial

• Published in: Progress in neuro-psychopharmacology & biological psychiatry Vol. 117; p. 110550
• Main Authors: Sarris, Jerome, Byrne, Gerard, Castle, David, Bousman, Chad, Oliver, Georgina, Cribb, Lachlan, Blair-West, Scott, Brakoulias, Vlasios, Camfield, David, Ee, Carolyn, Chamoli, Suneel, Boschen, Mark, Dean, Olivia M., Dowling, Nathan, Menon, Ranjit, Murphy, Jenifer, Metri, Najwa-Joelle, Nguyen, Thomas P., Wong, Andrew, Jordan, Rebecca, Karamacoska, Diana, Rossell, Susan L., Berk, Michael, Ng, Chee H.
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 13.07.2022
• Subjects: Anxiety; Clinical trial; Nutraceutical; Obsessive compulsive disorder; Oxidative stress; Obsessive compulsive disorder; Oxidative stress; Clinical trial; Anxiety; Nutraceutical
• ISSN: 0278-5846; 1878-4216
• DOI: 10.1016/j.pnpbp.2022.110550

Preliminary evidence has suggested that adjunctive N-acetylcysteine (NAC), an antioxidant precursor to glutathione, may reduce symptoms of obsessive-compulsive disorder (OCD). We conducted a 20-week, multi-site, randomized controlled trial to investigate the safety and efficacy of the adjunctive use of NAC in OCD. The study was a phase III, 20-week, double-blind, randomized controlled trial across multiple sites in Australia investigating 2 g to 4 g per day of NAC (titrated according to response) in 98 participants with DSM-5 diagnosed OCD. Data were analysed using linear mixed effects models for the 89 participants who attended at least one follow-up visit. A modified intention-to-treat analysis of the primary outcome found no evidence that NAC reduced symptoms of OCD measured on the Yale-Brown Obsessive-Compulsive Scale, relative to placebo (mean difference at week 20 = 0.53, 95% compatibility interval = −2.18, 3.23; p = 0.70; favouring placebo). There was also no evidence that NAC, compared to placebo, improved outcomes on the secondary measures including anxiety, depression, quality of life, functioning, or clinician/participant impression. NAC was well-tolerated with only mild gastrointestinal adverse events associated with the treatment. We found no evidence supporting the efficacy of the adjunctive use of NAC in OCD. •We conducted a randomized controlled trial to investigate the safety and efficacy of the adjunctive use of NAC in OCD•Results revealed no evidence that NAC reduced symptoms of OCD (measured on the Y-BOCS), relative to placebo•The mean difference at week 20 = 0.53, 95% compatibility interval = -2.18, 3.23; p = 0.70; favouring placebo•There was no evidence that NAC improved outcomes for secondary measures such as anxiety or depression, compared to placebo•NAC was well-tolerated with only mild gastrointestinal adverse events associated with the treatment