Hoarding in obsessive-compulsive disorder: clinical and genetic correlates

Hoarding may be an important symptom dimension in obsessive-compulsive disorder (OCD). Hoarding in OCD has been associated with poor insight, poorer response to selective serotonin reuptake inhibitors than other OCD symptom dimensions, and a distinctive psychobiological profile. The clinical and genetic correlates of hoarding in OCD therefore deserve additional investigation.

Adult OCD patients (N = 315) underwent a comprehensive clinical assessment that included the Structured Clinical Interview for DSM-IV Axis I Disorders (Patient Edition) and for Diagnosis of Obsessive-Compulsive Spectrum Disorders. DNA extracted from venous blood (10-30 mL) in a Caucasian subset of the interviewed OCD patients (N = 204) and Caucasian controls (N = 169), including patients (N = 94) and controls (N = 138) of Afrikaner descent, was genotyped to investigate polymorphisms in genes involved in monoamine function and previously hypothesized to be relevant to OCD. Data were collected from 1998 through 2004.

OCD patients with hoarding made up 18.1% of the total sample. Compared with nonhoarding OCD, OCD with hoarding was associated with a number of comorbid Axis I disorders, obsessive-compulsive personality disorder, significantly higher OCD severity scores, and more functional impairment. In subjects of Afrikaner descent, the L/L genotype of the COMT Val158Met polymorphism was significantly more common in the OCD hoarding group, with a preponderance of low activity alleles, compared with nonhoarding patients and controls.

These data are consistent with the hypothesis that hoarding represents a unique symptom subtype in OCD with a distinctive clinical and psychobiological profile. Further work is needed to determine the psychobiological mechanisms responsible for hoarding and to replicate the genetic findings noted here.