Hoarding in attention deficit hyperactivity disorder: Understanding the comorbidity

• Hoarding disorder has been associated with ADHD.
• Shared executive functioning deficits have been suggested to explain the comorbidity.
• A correlated liabilities model to understand the comorbidity is proposed.

Hoarding disorder has a frequent co-occurrence with attention-deficit/hyperactivity disorder (ADHD). An accurate understanding of the comorbidity between hoarding disorder and ADHD remains unclear but is essential to inform appropriate assessment, prevention and treatment approaches. This paper will provide a review of potential comorbidity models and aetiological mechanisms implicated in both disorders in order to inform understanding of the nature of the comorbidity between hoarding disorder and ADHD. A correlated liabilities model is identified that implicates genetic, neurological, and executive functioning factors in the development and maintenance of hoarding symptoms in individuals with ADHD.