Cluster analysis of obsessive-compulsive symptomatology: identifying obsessive-compulsive disorder subtypes.
BACKGROUND
There is increasing evidence that obsessive-compulsive disorder (OCD) is a heterogeneous disorder. Different clinical subtypes may be characterized by differing pathophysiological mechanisms and treatment outcomes.


METHODS
A cluster analysis was performed on 45 items of the Yale-Brown Obsessive-Compulsive Symptoms Checklist (YBOCS-CL) for 261 patients with OCD. Cluster solutions emerging at different linkage distance levels, and the associations of identified clusters with demographic, clinical and relevant genetic variables, were investigated.


RESULTS
A 6-cluster solution emerged at a linkage distance level of 1.5, and a 3-cluster solution emerged at a linkage distance level of 2.1. The 3 clusters in the latter solution were labeled I) Contamination / washing, II) Hoarding / symmetry / ordering, and III) Obsessional / checking. Increased Cluster III scores were associated with earlier age of OCD onset and the Met/Met (L/L) genotype of the COMT Val158Met polymorphism.


CONCLUSIONS
The data here are consistent with previous work delineating the different symptom subtypes of OCD, also with previous work suggesting that the Met/Met (L/L) genotype of the COMT Val158Met polymorphism may be associated with anxiety symptoms, as well as with previous work suggesting that dopaminergic genes may be particularly important in early-onset OCD.
Lochner
Christine
C
MRC Unit on Anxiety and Stress Disorders, Department of Psychiatry, University of Stellenbosch, South Africa. cl2@sum.ac.za
Hemmings
Sian M J
SM
Kinnear
Craig J
CJ
Nel
Daan
D
Hemmings
Sian M J
SM
Seedat
Soraya
S
Moolman-Smook
Johanna C
JC
Stein
Dan J
DJ
D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D002394:Catechol O-Methyltransferase / Q000235:genetics*; D016000:Cluster Analysis; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D009771:Obsessive-Compulsive Disorder / Q000145:classification* / Q000175:diagnosis / Q000235:genetics / Q000523:psychology*; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D020641:Polymorphism, Single Nucleotide; D055815:Young Adult
D002394:Catechol O-Methyltransferase