Neither age at the time of diagnosis nor YBOCS score was related to the presence of individual comorbidities or their general categories (infectious, autoimmune/inflammatory, or any immune-related comorbidity) (Supplementary Table S3). We next determined OCD symptom scores based on a previous factor analysis of symptoms in the YBOCS-CL (Bloch et al. 2008). Participants reporting at least one immune-related comorbidity had slightly higher scores for forbidden thoughts, cleaning, and hoarding (Supplementary Table S3). These differences were primarily driven by frequent ear or throat infections, the only condition with an increased score for cleaning-related symptoms that remained significant after adjustment for multiple comparisons [2.5 ± 0.9 vs. 2.3 ± 1.0, t(644) = 3.183, p = 0.002, n = 822]. There was no difference in YBOCS score or symptom severity based on gender.
