To the Editor: My associates and I thank Dr. Amdur for his comments on our recent publication. His letter raises several important issues regarding the diagnostic classification of the compulsive hoarding syndrome.

We agree with Dr. Amdur’s contention that compulsive hoarding should be removed from the diagnostic criteria for obsessive-compulsive personality disorder. Only 15%–45% of hoarders meet criteria for obsessive-compulsive personality disorder (1, 2). No correlation was found between hoarding severity and scores on an obsessive-compulsive personality disorder scale (3). Instead, hoarding behaviors correlate significantly with other OCD symptoms (3).

Dr. Amdur suggests that compulsive hoarders may not meet DSM-IV-TR criteria for OCD because they appear to suffer more from their inaction than from repetitive behaviors. However, compulsive hoarders have been found to have many repetitive acquisition and saving behaviors (3). While DSM-IV-TR does not explicitly mention compulsive hoarding as a symptom of OCD, hoarding and saving-related obsessions and compulsions are quite common in patients with OCD (4, 5) and are included in standard OCD assessments, such as the Yale-Brown Obsessive Compulsive Scale symptom checklist (6). Dr. Amdur observes that compulsive hoarders do not appear to have anxiety unless they are threatened by forced clearing, but several studies have found elevated anxiety levels in compulsive hoarders, even in comparison to nonhoarding OCD patients (7, 8). Moreover, hoarders also report a high prevalence of nonhoarding obsessions and compulsions (2, 3) and do not differ from nonhoarding OCD patients in the number of OCD symptoms reported on the Yale-Brown Obsessive Compulsive Scale checklist or overall score (7, 8).

Nevertheless, the question remains: Should compulsive hoarding be classified as a symptom subtype of OCD or as a separate disorder that is frequently comorbid with OCD? Factors that support a separate classification include significant differences between hoarders and nonhoarding OCD patients in comorbidity and family history (2), response to serotonin reuptake inhibitors (9), and the distinct functional brain abnormalities found in our recent study. Neuropsychological, brain imaging, and genetic studies comparing compulsive hoarders to nonhoarding OCD patients will be required to resolve this issue.

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