Differences in symptom severity in hoarding disorder between those with and without attention deficit-hyperactivity disorder.

Hoarding disorder (HD) is associated with symptoms of inattention. Previous studies relied on self-report assessments, which pose limitations in diagnosis; however no study has investigated the severity of hoarding in patients with and without comorbid attention-deficit/hyperactivity disorder (ADHD) using structured diagnostic interviews. A total of 68 patients met the diagnostic criteria for HD, including 20 (29 %) with comorbid ADHD (20/68). This study aimed to compare the severity of hoarding symptoms in HD patients diagnosed with and without ADHD using a structured interview. The participants with HD were divided into HD + ADHD and HD without ADHD (HD-noADHD) groups, diagnosed using the Conners' Adult ADHD Diagnostic Interview for Diagnostic and Statistical Manual of Mental Disorders and Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders. The severity of the hoarding symptoms was compared between the two groups using saving inventory-revised (SI-R), hoarding rating scale-self report(HRS-SR) and clutter image rating (CI-R). No significant differences were found between HD + ADHD and HD-noADHD groups in SI-R (p = 0.329), HRS-SR (p = 0.492) and CI-R (p = 0.589). These results suggest that diagnosis of ADHD was not related to HD severity.