Cognitive Functions in Obsessive Compulsive Disorder and Its Relationship with Oxidative Metabolism.

Abstract

Introduction: While data on oxidative stress in psychiatric disorders are increasing, studies on obsessive-compulsive disorder (OCD) are limited. Although many studies report neurocognitive deficits in OCD, to our knowledge, no study exists examining the relationship between neurocognitive functions and oxidative stress in OCD. This study investigated the neurocognitive functions in OCD and its relationship with OCD severity and oxidative metabolism.

Methods: In our study, 50 OCD patients and 50 healthy controls were included. The groups were well-matched for age, gender, education years, and other socio-demographic characteristics. Comorbid psychiatric diagnoses were excluded. To assess cognitive functions, a battery of neurocognitive tests was used. Oxidative metabolism parameters such as oxidants homocysteine, malondialdehyde, nitric oxide and antioxidants; sialic acid and glutathione peroxidase were measured. Obsessive-compulsive disorder severity was assessed with Yale-Brown-Obsession-Compulsion-Scale (YBOCS). Patients with OCD and control groups were compared in terms of neurocognitive functions, oxidative stress and OCD severity.

Results: OCD group performed significantly worse in various aspects of attention, memory, executive functions (p<0.05). Homocysteine, nitric oxide, malondialdehyde, sialic acid levels were significantly (p<0.05) higher, glutathione peroxidase was significantly (p<0.05) lower in patients versus controls. Yale-Brown-Obsession-Compulsion-Scale scores correlated negatively with most of neurocognitive functions. The relationship between oxidative parameters and cognitive tests was contradictory as some results were opposite to what was expected.

Conclusions: Cognition is affected by OCD and worsens with disorder severity. Considering oxidative parameters were meaningful in patients, oxidative metabolism may be a risk factor for OCD. However, more studies are needed to evaluate the effect of oxidative metabolism on cognitive functions.