Psychological Medicine

Table of Contents - 2007 - Volume 37, Issue 01  


Original Article

Obsessive–compulsive disorder, tics and anxiety in 6-year-old twins

DEREK BOLTON a1c1, FRÜHLING RIJSDIJK a1, THOMAS G. O'CONNOR a1, SEAN PERRIN a1 and THALIA C. ELEY a1
a1 Institute of Psychiatry, Kings College London, UK

Article author query
bolton d   [PubMed][Google Scholar] 
rijsdijk f   [PubMed][Google Scholar] 
o'connor tg   [PubMed][Google Scholar] 
perrin s   [PubMed][Google Scholar] 
eley tc   [PubMed][Google Scholar] 

Abstract

Background. Previous reports of genetic influences on obsessive–compulsive disorder (OCD) symptoms have suggested moderate heritability. Family history studies of co-morbidity have found familial aggregation with tics, especially for early-onset OCD, and familial aggregation with anxiety disorders.

Method. Heritability of OCD and familial aggregation of OCD, tics and anxiety disorders were investigated in a community sample of 6-year-old twins using a two-phase design in which 4662 twin pairs were sampled and 854 pairs were assessed in the second phase by maternal-informant diagnostic interview using DSM-IV criteria.

Results. In the multivariate model combined additive genetic and common environmental effects were estimated as 47% for sub-threshold OCD, and the model was unable to distinguish these sources of familial aggregation. There were strong familial aggregations between sub-threshold OCD and tics and between sub-threshold OCD and other anxiety disorders (80% and 97% respectively), although again specific sources could not be distinguished.

Conclusions. The findings are consistent with the hypothesis of a tic-related early-onset OCD phenotype, but also with the hypothesis of an anxiety-related early-onset OCD phenotype.

(Published Online September 26 2006)


Correspondence:
c1 Psychology Department, Institute of Psychiatry PO Box 77, De Crespigny Park, London SE5 8AF, UK. (Email: d.bolton@iop.kcl.ac.uk).

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