Ma. Grados et al., The familial phenotype of obsessive-compulsive disorder in relation to ticdisorders: The Hopkins OCD family study, BIOL PSYCHI, 50(8), 2001, pp. 559-565
Background: Obsessive-compulsive disorder (OCD) and tic disorders have phen
omenological and familial-genetic overlaps. An OCD family study sample that
excludes Tourette's syndrome in probands is used to examine whether tic di
sorders are part of the familial phenotype of OCD.
Methods: Eighty case and 73 control probands and their first-degree relativ
es were examined by experienced clinicians using the Schedule for Affective
Disorders and Schizophrenia-Lifetime Anxiety version. DSM-IV psychiatric d
iagnoses were ascertained by a best-estimate consensus procedure. The preva
lence and severity of tic disorders, age-at-onset of OCD symptoms, and tran
smission of OCD and tic disorders by characteristics and type of proband (O
CD + tic disorder, OCD - tic disorder) were examined in relatives.
Results: Case probands and case relatives had a greater lifetime prevalence
of tic disorders compared to control subjects. Tic disorders spanning a wi
de severity range were seen in case relatives; only mild severity was seen
in control relatives. Younger age-at-onset of OCD symptoms and possibly mal
e gender in case probands were associated with increased tic disorders in r
elatives. Although relatives of OCD + tic disorder and OCD - tic disorder p
robands had similar prevalences of tic disorders, this result is not conclu
sive.
Conclusions: Tic disorders constitute an alternate expression of the famili
al OCD phenotype. (C) 2001 Society of Biological Psychiatry.