title: Is obsessive-compulsive disorder an anxiety disorder, and what, if any, are spectrum conditions? A family study perspective.
abstract: BACKGROUND
  Experts have proposed removing obsessive-compulsive disorder (OCD) from the anxiety disorders section and grouping it with putatively related conditions in DSM-5. The current study uses co-morbidity and familiality data to inform these issues.
  
  
  METHODS
  Case family data from the OCD Collaborative Genetics Study (382 OCD-affected probands and 974 of their first-degree relatives) were compared with control family data from the Johns Hopkins OCD Family Study (73 non-OCD-affected probands and 233 of their first-degree relatives).
  
  
  RESULTS
  Anxiety disorders (especially agoraphobia and generalized anxiety disorder), cluster C personality disorders (especially obsessive-compulsive and avoidant), tic disorders, somatoform disorders (hypochondriasis and body dysmorphic disorder), grooming disorders (especially trichotillomania and pathological skin picking) and mood disorders (especially unipolar depressive disorders) were more common in case than control probands; however, the prevalences of eating disorders (anorexia and bulimia nervosa), other impulse-control disorders (pathological gambling, pyromania, kleptomania) and substance dependence (alcohol or drug) did not differ between the groups. The same general pattern was evident in relatives of case versus control probands. Results in relatives did not differ markedly when adjusted for demographic variables and proband diagnosis of the same disorder, though the strength of associations was lower when adjusted for OCD in relatives. Nevertheless, several anxiety, depressive and putative OCD-related conditions remained significantly more common in case than control relatives when adjusting for all of these variables simultaneously.
  
  
  CONCLUSIONS
  On the basis of co-morbidity and familiality, OCD appears related both to anxiety disorders and to some conditions currently classified in other sections of DSM-IV.
authors: Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA. jbienven@jhmi
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mesh_terms: D000293:Adolescent; D000328:Adult; D001008:Anxiety Disorders / Q000145:classification / Q000453:epidemiology* / Q000235:genetics / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D015897:Comorbidity; D039721:Diagnostic and Statistical Manual of Mental Disorders; D004812:Epidemiologic Methods; D005190:Family / Q000523:psychology*; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D007406:Interview, Psychological; D008297:Male; D001523:Mental Disorders / Q000145:classification / Q000453:epidemiology* / Q000235:genetics; D008875:Middle Aged; D009771:Obsessive-Compulsive Disorder / Q000145:classification / Q000453:epidemiology / Q000235:genetics / Q000473:pathology; D010641:Phenotype; D012959:Socioeconomic Factors; D055815:Young Adult