Brain specimens (N = 16) were obtained through the University of Pittsburgh Brain Tissue Donation Program during autopsies conducted by the Allegheny County Medical Examiner’s Office (Pittsburgh, PA) after consent was given by next-of-kin. An independent panel of experienced clinicians reviewed findings from structured interviews with family members, clinical records, toxicology, and neuropathology to make consensus DSM-IV diagnoses. Unaffected comparison subjects underwent identical assessments and were determined to be free of any lifetime psychiatric illnesses. All procedures were approved by the University of Pittsburgh’s Committee for the Oversight of Research and Clinical Training Involving Decedents and Institutional Review Board for Biomedical Research. To reduce biological variance between groups, each subject with OCD (N = 8) was matched with one unaffected comparison subject for sex (8 males and 8 females), age (standard error of the difference (SED = 0.29), post-mortem interval (PMI; SED = 3.18), and tissue pH (SED = 0.076). The age of unaffected comparison subjects ranged from 20 to 65 years, while the age of OCD subjects ranged from 20 to 69 years (Table 1).Table 1Cohort demographics.OCD subjectsUnaffected comparison
