title: Understanding the heterogeneity of OCD.
authors.forename: John E
authors.initials: JE
authors.lastname: Calamari
mesh_terms: D017668:Age of Onset; D016000:Cluster Analysis; D015897:Comorbidity; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005163:Factor Analysis, Statistical; D006801:Humans; D009771:Obsessive-Compulsive Disorder / Q000145:classification* / Q000175:diagnosis* / Q000453:epidemiology; D011569:Psychiatric Status Rating Scales; D011594:Psychometrics; D020323:Tics / Q000145:classification / Q000175:diagnosis / Q000453:epidemiology