title: Early-onset obsessive-compulsive disorder: a subgroup with a specific clinical and familial pattern?
abstract: BACKGROUND
  The familial nature of obsessive-compulsive disorder (OCD) has been previously demonstrated. The identification of candidate symptoms such as age at onset may help to disentangle the clinical and genetic heterogeneity of the disorder. In this study, the specificity of early-onset OCD was investigated, focusing on the effect of gender, comorbid conditions and familial risk of tics and OCD by studying a population consisting exclusively of patients with early-onset OCD.
  
  
  METHODS
  One hundred and forty-four patients having OCD were recruited in the study (108 early-onset probands and 36 late-onset probands). The early-onset probands and 199 of their first-degree relatives were investigated using structured interviews and questionnaires. This sample of early onset was mainly composed of children and adolescents (74 children and adolescents and 34 adults).
  
  
  RESULTS
  The average age of onset of OCD is 9.98+/-3.2 years. Forty-four per cent of the probands have a comorbid tic disorder. The age-corrected morbid risk among the first-degree relatives is 17% for OCD and 12% for tics. Morbid risk for OCD and tics was independent of the presence of tics in probands. Only 32.6% of the probands have a positive family history of OCD.
  
  
  CONCLUSIONS
  These findings are consistent with other reports in the literature that the morbid risk of OCD is elevated in relatives of probands with early-onset OCD. However, the majority of cases do not have a positive family history of OCD. This result suggests that early onset is not the only specific clinical marker for familial risk in OCD. Thus more work is needed to clearly elucidate other factors related to increased genetic vulnerability for OCD.
authors: Service de psychopathologie de l'enfant et de l'adolescent, Assistance Publique-Hôpitaux de Paris, Hôpital Robert Debré, Paris, France. chabane@im3.inserm.fr
authors: Nadia
authors: N
authors: Chabane
authors: Richard
authors: R
authors: Delorme
authors: Bruno
authors: B
authors: Millet
authors: Marie-Christine
authors: MC
authors: Mouren
authors: Marion
authors: M
authors: Leboyer
authors: David
authors: D
authors: Pauls
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D009771:Obsessive-Compulsive Disorder / Q000453:epidemiology / Q000235:genetics* / Q000523:psychology*; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires; D005879:Tourette Syndrome / Q000453:epidemiology