Familiality of factor analysis-derived YBOCS dimensions in OCD-affected sibling pairs from the OCD Collaborative Genetics Study.
BACKGROUND
Identification of familial, more homogenous characteristics of obsessive-compulsive disorder (OCD) may help to define relevant subtypes and increase the power of genetic and neurobiological studies of OCD. While factor-analytic studies have found consistent, clinically meaningful OCD symptom dimensions, there have been only limited attempts to evaluate the familiality and potential genetic basis of such dimensions.


METHODS
Four hundred eighteen sibling pairs with OCD were evaluated using the Structured Clinical Interview for DSM-IV and the Yale-Brown Obsessive Compulsive Scale (YBOCS) Symptom Checklist and Severity scales.


RESULTS
After controlling for sex, age, and age of onset, robust sib-sib intraclass correlations were found for two of the four YBOCS factors: Factor IV (hoarding obsessions and compulsions (p = .001) and Factor I (aggressive, sexual, and religious obsessions, and checking compulsions; p = .002). Smaller, but still significant, familiality was found for Factor III (contamination/cleaning; p = .02) and Factor II (symmetry/ordering/arranging; p = .04). Limiting the sample to female subjects more than doubled the familiality estimates for Factor II (p = .003). Among potentially relevant comorbid conditions for genetic studies, bipolar I/II and major depressive disorder were strongly associated with Factor I (p < .001), whereas ADHD, alcohol dependence, and bulimia were associated with Factor II (p < .01).


CONCLUSIONS
Factor-analyzed OCD symptom dimensions in sibling pairs with OCD are familial with some gender-dependence, exhibit relatively specific relationships to comorbid psychiatric disorders and thus may be useful as refined phenotypes for molecular genetic studies of OCD.
Hasler
Gregor
G
Laboratory of Clinical Science, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland.
Pinto
Anthony
A
Greenberg
Benjamin D
BD
Samuels
Jack
J
Fyer
Abby J
AJ
Pauls
David
D
Knowles
James A
JA
McCracken
James T
JT
Piacentini
John
J
Riddle
Mark A
MA
Rauch
Scott L
SL
Rasmussen
Steven A
SA
Willour
Virginia L
VL
Grados
Marco A
MA
Cullen
Bernadette
B
Bienvenu
O Joseph
OJ
Shugart
Yin-Yao
YY
Liang
Kung-Yee
KY
Hoehn-Saric
Rudolf
R
Wang
Ying
Y
Ronquillo
Jonne
J
Nestadt
Gerald
G
Murphy
Dennis L
DL
D015897:Comorbidity; D005163:Factor Analysis, Statistical; D005192:Family Health; D005260:Female; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000453:epidemiology; D009771:Obsessive-Compulsive Disorder / Q000453:epidemiology / Q000235:genetics* / Q000503:physiopathology*; D015995:Prevalence; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D012801:Sibling Relations; D035781:Siblings