Poor memory confidence mediates the association between inattention symptoms and hoarding severity and impairment

• Inattention symptoms have been linked to increased hoarding severity.
• We used serial mediation to test mechanisms linking inattention to HD severity.
• Memory confidence mediated the relationship between inattention and HD severity.
• Final model: inattention → poor memory confidence → saving → clutter → impairment.
• The final model accounted for >90% of the variance in HD-related impairment.

Hoarding disorder (HD) is characterized by excessive saving and difficulty discarding possessions, which results in severe clutter and functional impairment. HD shows patterns of elevated comorbidity with the inattentive subtype of attention deficit-hyperactivity disorder (ADHD-I). ADHD-I symptoms are associated with more severe HD pathology (Tolin, Villavicencio, Umbach, & Kurtz, 2011), but the mechanisms underlying this association are unclear. The present study used serial mediation analyses in a sample of individuals with HD (n=32) and healthy controls (n=26) to test one potential pathway: ADHD-I symptoms lead to poor memory confidence, which leads to excessive saving of possessions to facilitate remembering, which in turn leads to clutter and corresponding functional impairment. The model provided a strong fit for the data, accounting for over 90% of the variance in functional impairment. Alternate models that did not include ADHD-I symptoms and poor memory confidence provided a weaker fit. These findings support and extend leading cognitive-behavioral conceptualizations of HD (e.g., Frost & Hartl, 1996) and point to inattention symptoms and memory confidence as potential targets for HD prevention and intervention research.