This descriptive study used self-report medical questionnaires from a large cohort of patients with childhood-onset OCD to estimate the lifetime prevalence of immune-related medical comorbidities. Self-reported lifetime prevalence of encephalitis or meningitis, scarlet fever, RF, and RA was greater than expected in probands with OCD and in their OCD-affected and unaffected first-degree relatives. Similar rates of RF, encephalitis or meningitis, and scarlet fever were identified in first-degree relatives independent of OCD status, suggesting that—if reflective of true increased prevalence—such comorbidities may represent common familial traits and genetic vulnerability rather than state markers of disease.
