title: Obsessive-compulsive disorder: subclassification based on co-morbidity.
abstract: BACKGROUND
  Obsessive-compulsive disorder (OCD) is probably an etiologically heterogeneous condition. Many patients manifest other psychiatric syndromes. This study investigated the relationship between OCD and co-morbid conditions to identify subtypes.
  
  
  METHODS
  Seven hundred and six individuals with OCD were assessed in the OCD Collaborative Genetics Study (OCGS). Multi-level latent class analysis was conducted based on the presence of eight co-morbid psychiatric conditions [generalized anxiety disorder (GAD), major depression, panic disorder (PD), separation anxiety disorder (SAD), tics, mania, somatization disorders (Som) and grooming disorders (GrD)]. The relationship of the derived classes to specific clinical characteristics was investigated.
  
  
  RESULTS
  Two and three classes of OCD syndromes emerge from the analyses. The two-class solution describes lesser and greater co-morbidity classes and the more descriptive three-class solution is characterized by: (1) an OCD simplex class, in which major depressive disorder (MDD) is the most frequent additional disorder; (2) an OCD co-morbid tic-related class, in which tics are prominent and affective syndromes are considerably rarer; and (3) an OCD co-morbid affective-related class in which PD and affective syndromes are highly represented. The OCD co-morbid tic-related class is predominantly male and characterized by high conscientiousness. The OCD co-morbid affective-related class is predominantly female, has a young age at onset, obsessive-compulsive personality disorder (OCPD) features, high scores on the 'taboo' factor of OCD symptoms, and low conscientiousness.
  
  
  CONCLUSIONS
  OCD can be classified into three classes based on co-morbidity. Membership within a class is differentially associated with other clinical characteristics. These classes, if replicated, should have important implications for research and clinical endeavors.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD 21287, USA. gnestadt@jhmi.edu
authors.forename: G
authors.initials: G
authors.lastname: Nestadt
authors.forename: C Z
authors.initials: CZ
authors.lastname: Di
authors.forename: M A
authors.initials: MA
authors.lastname: Riddle
authors.forename: M A
authors.initials: MA
authors.lastname: Grados
authors.forename: B D
authors.initials: BD
authors.lastname: Greenberg
authors.forename: A J
authors.initials: AJ
authors.lastname: Fyer
authors.forename: J T
authors.initials: JT
authors.lastname: McCracken
authors.forename: S L
authors.initials: SL
authors.lastname: Rauch
authors.forename: D L
authors.initials: DL
authors.lastname: Murphy
authors.forename: S A
authors.initials: SA
authors.lastname: Rasmussen
authors.forename: B
authors.initials: B
authors.lastname: Cullen
authors.forename: A
authors.initials: A
authors.lastname: Pinto
authors.forename: J A
authors.initials: JA
authors.lastname: Knowles
authors.forename: J
authors.initials: J
authors.lastname: Piacentini
authors.forename: D L
authors.initials: DL
authors.lastname: Pauls
authors.forename: O J
authors.initials: OJ
authors.lastname: Bienvenu
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.forename: K Y
authors.initials: KY
authors.lastname: Liang
authors.forename: J F
authors.initials: JF
authors.lastname: Samuels
authors.forename: K Bandeen
authors.initials: KB
authors.lastname: Roche
mesh_terms: D000328:Adult; D000367:Age Factors; D017668:Age of Onset; D015897:Comorbidity; D003430:Cross-Sectional Studies; D003865:Major Depressive Disorder / Q000145:classification / Q000175:diagnosis / Q000235:genetics / Q000523:psychology; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000145:classification* / Q000175:diagnosis / Q000235:genetics / Q000523:psychology; D009771:Obsessive-Compulsive Disorder / Q000145:classification* / Q000175:diagnosis / Q000235:genetics / Q000523:psychology; D010552:Personality Assessment / Q000706:statistics & numerical data; D010554:Personality Disorders / Q000145:classification / Q000175:diagnosis / Q000235:genetics / Q000523:psychology; D011594:Psychometrics; D012737:Sex Factors; D013981:Tic Disorders / Q000145:classification / Q000175:diagnosis / Q000235:genetics / Q000523:psychology