Distinct clinical phenotypes of pediatric Obsessive-Compulsive Disorder with and without neurodevelopmental disorders: evidence for a neurodevelopmental continuum

This study aimed to investigate clinical, demographic, and psychopathological differences between pediatric patients with obsessive-compulsive disorder (OCD) with and without comorbid neurodevelopmental disorders (NDDs), focusing on symptom presentation, comorbidities, and functional outcomes. A total of 121 drug-naïve children and adolescents with recent-onset OCD (66 with comorbid NDDs and 55 without) were assessed at the Child and Adolescent Neuropsychiatry Unit of Bambino Gesù Children’s Hospital. Participants underwent multidisciplinary clinical evaluations, including structured diagnostic interviews (Schedule for Affective Disorders and Schizophrenia for School-Aged Children – Present and Lifetime Version for DSM-5 K-SADS-PL DSM-5), symptom-specific scales (Children’s Yale-Brown Obsessive Compulsive Scale [CY-BOCS], Children’s Depression Inventory 2 [CDI-2], Multidimensional Anxiety Scale for Children 2 [MASC-2]), and adaptive functioning assessments (Children’s Global Assessment Scale [CGAS]). The OCD + NDDs group was significantly younger, had lower IQ, and showed a male predominance, but did not differ in global functioning. No significant differences were found in anxiety or depressive symptoms across groups. However, distinct OCD symptom profiles emerged: sexual and forbidden thought obsessions as derived by CY-BOCS were more frequent in the OCD-NDDs group, while hoarding compulsions were more common in OCD + NDDs. Comorbid tics and ADHD were significantly more prevalent in the OCD + NDDs group, whereas PTSD was more frequent in OCD-NDDs. Findings support the presence of distinct phenotypic and comorbidity profiles in pediatric OCD with and without NDDs, emphasizing the need for tailored diagnostic and therapeutic approaches. While internalizing symptoms may remain comparable, the variation in obsessional content and neurodevelopmental burden highlights the clinical importance of early, individualized assessment strategies.