Oxidative and nitrosative stress markers in obsessive-compulsive disorder: a systematic review and meta-analysis Maia A, Oliveira J, Lajnef M, Mallet L, Tamouza R, Leboyer M, Oliveira-Maia AJ. Oxidative and nitrosative stress markers in obsessive-compulsive disorder: a systematic review and meta-analysis Objective: Obsessive-compulsive disorder (OCD) is a chronic, prevalent, and highly impairing psychiatric illness. Although the pathophysiology of OCD remains unknown, pathways involved in oxidative and nitrosative stress (O&NS) have been implicated. The present study aims to systematically review the literature for quantitative evidence that patients with OCD have altered measures of blood O&NS markers. Methods: Independent random-effects meta-analyses using standardized mean differences were conducted to assess each marker separately. Additionally, data from multiple markers were pooled together in a metaanalysis for measures of oxidant activity and another for measures of antioxidant activity. Results: Thirteen studies met inclusion criteria, involving 433 OCD patients and 459 controls. Eleven blood O&NS markers were eligible for independent quantitative analyses. We found that, in OCD patients, the oxidant markers 8-hydroxydeoxyguanosine and malondialdehyde, and the antioxidants glutathione peroxidase and superoxide dismutase, were significantly increased while total antioxidant status, vitamin C, and vitamin E were significantly decreased, when comparing with controls. Regarding pooled meta-analyses, we found a statistically significant increase in oxidant markers, but non-significant results regarding antioxidant markers. Conclusions: Our meta-analysis suggests that OCD patients have a systemic oxidative imbalance that is not adequately buffered by the antioxidant system. Additional studies are needed in order to support this association.
Summations• Patients with obsessive-compulsive disorder have a dysregulated oxidative profile with increased blood oxidative markers.• No global changes in antioxidant defenses in obsessive-compulsive disorder are of remark thus suggesting that oxidative stress is not adequately buffered.• Our results underline the systemic impact of obsessive-compulsive disorder and should motivate the development of future studies in order to better understand this association.
Considerations• Most studies did not provide measurements of oxidative and nitrosative stress markers according to pertinent demographic and clinical characteristics thus impairing relevant sensitivity analyses that would have allowed to assess the potential impact of these factors in the results.• The limited number of studies, their moderate quality and heterogeneity, and the evidence for publication bias prevent more robust conclusions.