State of the Science: Hoarding Disorder and Its Treatment.

This state-of-the-science review describes the relatively new diagnosis of hoarding disorder (HD), characterized by difficulty discarding possessions and resulting clutter in living spaces. We review current theoretical models of HD, including a cognitive-behavioral model, a biopsychosocial model, an attachment model, and an addictions model. We then describe interventions for HD, focusing largely on cognitive-behavioral therapy for hoarding disorder (CBT-HD), the only treatment with conclusive evidence of efficacy. We review the components of CBT-HD and their rationale, noting that clinical results have been modest. The cross-cultural efficacy of CBT-HD is unclear, as are the effects of cultural modifications to the treatment. Future clinical and research directions are discussed.