ABSTRACT
Despite the long-held view that hoarding is a symptom of both obsessive-compulsive disorder and obsessive-compulsive personality disorder, increased evidence has emerged during the last 20 years suggesting that hoarding represents a distinct form of psychopathology. This study reflects the discussions on the nosological status of hoarding carried out by the WHO ICD-11 Working Group on the Classification of Obsessive-Compulsive and Related Disorders. The distinctiveness of hoarding is based on its having core symptoms that differ from those of other disorders, as well as distinctive neurobiological correlates and treatment responses. Furthermore, data showing the clinical utility, global applicability, and appropriateness of the concept of hoarding disorder outside specialty mental health settings suggest that this condition should be included in ICD-11. Finally, given the focus of ICD-11 on primary care and public health, the Working Group suggests that poor insight and severe domestic squalor may be considered as specifiers for hoarding disorder in ICD-11.