Serum Claudin-5, but not Zonulin, May Be Associated with Obsessive-Compulsive Disorder.

BACKGROUND: The aim of this research was to assess serum zonulin and claudin-5 concentrations to show whether or not their eventual changes in patients with obsessive-compulsive disorder (OCD) could have etiopathogenetic importance. There was no research in the literature assessing serum zonulin and claudin-5 levels in OCD to the best of our understanding. SUBJECTS AND METHODS: In this study, we assumed that there may be a deterioration in serum zonulin and claudin-5 levels in OCD patients and this may affect the severity of the disease. Thirty-six OCD patients and 35 healthy controls were included in this study. The patients were administered Hamilton Depression Rating Scale (HDRS) and Yale-Brown Obsession Compulsion Scale (Y-BOCS) to determine the severity of depression and OCD, respectively. Venous blood samples were collected, and serum zonulin and claudin-5 levels were measured. RESULTS: The mean serum claudin-5 level was significantly higher without a significant difference between age, sex, and body mass index, whereas serum zonulin level was not different from the control group in OCD patients. CONCLUSIONS: In conclusion, the current research indicates that claudin-5 is enhanced in OCD patients and this finding may contribute to the role of blood-brain barrier in the pathogenesis of OCD.