Visually mediated functioning improves following treatment of hoarding disorder

Background: Hoarding disorder (HD) is a highly debilitating psychiatric disorder that affects 2-6% of adults. Neuropsychological deficits in visual memory, detection, and categorization have been reported in HD. To date, no study has examined the relationship between neurocognitive functioning and treatment for HD. We aim to determine the association between neurocognitive functioning and treatment outcomes, as well as the impact of HD-specific treatment on cognitive functioning. Methods: 323 individuals with HD were randomized to 20 weeks of peer- or clinician-led group behavioral treatment. 242 participants completed pre- and post-treatment neuropsychological testing covering eight neurocognitive domains. Rates of cognitive impairment (CI) were assessed for each neurocognitive domain. The association of baseline neurocognitive function on treatment response was examined using multiple regression. MANOVA and post-hoc tests were used to determine neurocognitive performance change pre- to post treatment. Results: Sixty-seven percent of participants had CI on ≥1 cognitive domain. There was no significant effect of pre-treatment neurocognitive functioning on treatment outcome. Post-treatment improvements were observed in visual memory, visual detection, decision making, information processing speed, visuospatial processing, attention/working memory (p≤.001). Declines in performance were found in visual reaction time and categorization. Limitations: This was a non-inferiority trial to examine two treatment types with no normative comparison group. Treatment seeking individuals are more likely to be insightful, motivated, and have other features which limit generalizability. Conclusions: Patterns of cognitive impairment in HD are similar to previous reports. Pre-treatment neurocognitive functioning did not impact treatment response. Neuropsychological functioning improved across multiple domains following targeted treatment.