Expression levels of miR-132, miR-134, and miR-195 in treatment-naïve children and adolescents with obsessive–compulsive disorder: a case-control study

Obsessive–compulsive disorder (OCD) is a chronic neuropsychiatric condition characterized by obsessions and/or compulsions and arises from a complex interaction of genetic and environmental factors. Emerging evidence suggests that microRNAs (miRNAs) may play a role in the neurobiological mechanisms underlying psychiatric disorders; however, their involvement in pediatric OCD remains unclear. This study aimed to compare serum expression levels of selected miRNAs between children and adolescents with OCD and healthy controls. This study included 50 children and adolescents with OCD and 44 age- and sex-matched healthy controls, all aged 8–18 years. Obsessive–compulsive symptom severity was assessed using the Children’s Yale–Brown Obsessive Compulsive Scale (CY-BOCS), while anxiety and depressive symptoms were evaluated using the Screen for Child Anxiety Related Emotional Disorders (SCARED) and the Children’s Depression Inventory (CDI), respectively. Serum expression levels of miR-132, miR-134, and miR-195 were quantified using quantitative real-time polymerase chain reaction (RT-qPCR). Group differences in miRNA expression were assessed using Mann–Whitney U tests or independent-samples t-tests, and correlations with clinical scores were evaluated using Spearman’s correlation, with Bonferroni correction applied for multiple comparisons. Expression levels of miR-132 and miR-195 were significantly higher in children and adolescents with OCD compared to healthy controls, whereas miR-134 levels did not differ between groups. An analysis of covariance was performed after adjusting for potential confounding variables, including age, sex, and the severity of depressive and anxiety symptoms, and the findings remained unchanged. MiR-134 expression differed across OCD severity subgroups, with higher levels observed in the mild group compared to the moderate group. In contrast, miR-132 and miR-195 showed no association with OCD severity, and none of the three miRNAs were significantly associated with anxiety or depressive symptom scores. The findings suggest that miR-132 and miR-195 may be associated with pediatric OCD and represent candidate molecular markers warranting further investigation. In contrast, miR-134 may be related to clinical heterogeneity. Overall, these results underscore the complex role of miRNAs in OCD and highlight the need for replication in larger and longitudinal studies. Not applicable.