Psychiatry - Research Publications
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ItemNo Preview AvailableN-acetyl cysteine (NAC) augmentation in the treatment of obsessive-compulsive disorder: A phase III, 20-week, double-blind, randomized, placebo-controlled trial.(Elsevier BV, 2022-07-13)OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: We found no evidence supporting the efficacy of the adjunctive use of NAC in OCD.
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ItemNo Preview AvailableTreatment of refractory obsessive-compulsive disorder with nutraceuticals (TRON): a 20-week, open label pilot study(CAMBRIDGE UNIV PRESS, 2022-10-21)BACKGROUND: Obsessive-compulsive disorder (OCD) is often challenging to treat and resistant to psychological interventions and prescribed medications. The adjunctive use of nutraceuticals with potential neuromodulatory effects on underpinning pathways such as the glutamatergic and serotonergic systems is one novel approach. OBJECTIVE: To assess the effectiveness and safety of a purpose-formulated combination of nutraceuticals in treating OCD: N-acetyl cysteine, L-theanine, zinc, magnesium, pyridoxal-5' phosphate, and selenium. METHODS: A 20-week open label proof-of-concept study was undertaken involving 28 participants with treatment-resistant DSM-5-diagnosed OCD, during 2017 to 2020. The primary outcome measure was the Yale-Brown Obsessive-Compulsive Scale (YBOCS), administered every 4 weeks. RESULTS: An intention-to-treat analysis revealed an estimated mean reduction across time (baseline to week-20) on the YBOCS total score of -7.13 (95% confidence interval = -9.24, -5.01), with a mean reduction of -1.21 points per post-baseline visit (P ≤ .001). At 20-weeks, 23% of the participants were considered "responders" (YBOCS ≥35% reduction and "very much" or "much improved" on the Clinical Global Impression-Improvement scale). Statistically significant improvements were also revealed on all secondary outcomes (eg, mood, anxiety, and quality of life). Notably, treatment response on OCD outcome scales (eg, YBOCS) was greatest in those with lower baseline symptom levels, while response was limited in those with relatively more severe OCD. CONCLUSIONS: While this pilot study lacks placebo-control, the significant time effect in this treatment-resistant OCD population is encouraging and suggests potential utility especially for those with lower symptom levels. Our findings need to be confirmed or refuted via a follow-up placebo-controlled study.
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ItemN-Acetyl Cysteine in the Treatment of Obsessive Compulsive and Related Disorders: A Systematic Review(KOREAN COLL NEUROPSYCHOPHARMACOLOGY, 2015-04)OBJECTIVE: Obsessive compulsive and related disorders are a collection of debilitating psychiatric disorders in which the role of glutamate dysfunction in the underpinning neurobiology is becoming well established. N-acetyl cysteine (NAC) is a glutamate modulator with promising therapeutic effect. This paper presents a systematic review of clinical trials and case reports exploring the use of NAC for these disorders. A further objective was to detail the methodology of current clinical trials being conducted in the area. METHODS: PubMed, Web of Science and Cochrane Library Database were searched for human clinical trials or case reports investigating NAC in the treatment of obsessive compulsive disorder (OCD) or obsessive compulsive related disorders. Researchers with known involvement in NAC studies were contacted for any unpublished data. RESULTS: Four clinical trials and five case reports/series were identified. Study durations were commonly 12-weeks, using 2,400-3,000 mg/day of NAC. Overall, NAC demonstrates activity in reducing the severity of symptoms, with a good tolerability profile and minimal adverse effects. Currently there are three ongoing randomized controlled trials using NAC for OCD (two adults and one pediatric), and one for excoriation. CONCLUSIONS: Encouraging results have been demonstrated from the few pilot studies that have been conducted. These results are detailed, in addition to a discussion of future potential research.
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ItemN-Acetyl Cysteine (NAC) in the Treatment of Obsessive-Compulsive Disorder: A 16-Week, Double-Blind, Randomised, Placebo-Controlled Study(ADIS INT LTD, 2015-09)BACKGROUND: Obsessive-compulsive disorder (OCD) is a disabling mental illness for which pharmacological and psychosocial interventions are all too often inadequate. Recent preclinical and clinical studies have implicated dysfunction of glutamatergic neurotransmission in the pathophysiology of OCD. The amino acid-based nutraceutical N-acetyl cysteine (NAC) is a safe and readily available agent that has been found to modify the synaptic release of glutamate in subcortical brain regions via modulation of the cysteine-glutamate antiporter. OBJECTIVE: The aim of this study was to assess the efficacy and safety of NAC in treating OCD. METHODS: A 16-week, double-blind, placebo-controlled, randomised trial using 3 g/day of NAC (1.5 g twice daily) in 44 participants (aged 18-70 years) with Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5)-diagnosed OCD, during 2013-2015. The primary outcome measure was the Yale-Brown Obsessive Compulsive Scale (YBOCS), conducted every 4 weeks. RESULTS: Analysis of the full sample (intention-to-treat) with repeated measures mixed linear modelling revealed a nonsignificant time × treatment interaction for the YBOCS scale total score (p = 0.39). A per-protocol analysis removing protocol violators also failed to show a significant time × treatment interaction for YBOCS total score (p = 0.15). However, a significant time × treatment interaction was observed for the YBOCS 'Compulsions' subscale in favour of NAC (p = 0.013), with a significant reduction observed at week 12 (dissipating at week 16). At 16 weeks, only four (20%) participants were considered 'responders' (YBOCS ≥35% reduction at endpoint) versus four (27%) in the placebo group. The NAC was well-tolerated, aside from more cases of heartburn occurring compared with placebo (p = 0.045). CONCLUSION: Further research involving NAC for OCD may require larger samples to detect moderate or small effect sizes, involve dosage or formulation differences, use in concert with exposure therapy, or an additional post-study observational period to mitigate study withdrawal. TRIAL REGISTRATION: ACTRN12613000310763.