A Multitrait-Multimethod Matrix Investigation of Hoarding

Area of Science:

• Psychiatry
• Mental Health
• Behavioral Science

Background:

• Hoarding disorder was previously considered a subtype of obsessive-compulsive disorder (OCD).
• Emerging research indicates hoarding disorder is distinct from and more prevalent than OCD.
• Key features include excessive acquisition, difficulty discarding, and clutter, but their interrelation is understudied.

Purpose of the Study:

• To investigate the role of the three core features in defining hoarding disorder.
• To assess the convergent and discriminant validity of these hoarding factors.
• To determine if hoarding features differentiate hoarding disorder from OCD and community controls.

Main Methods:

• Utilized a multitrait-multimethod matrix to examine validity of hoarding factors.
• Factor analytic studies of hoarding scales identified three key features.
• Compared individuals with hoarding disorder, OCD, and community controls.

Main Results:

• The three-factor model of hoarding showed adequate fit with high convergent validity.
• Poor discriminant validity was observed among the hoarding factors.
• Each hoarding feature distinguished hoarding participants from OCD patients and controls, but not OCD from controls.

Conclusions:

• Findings suggest a more parsimonious view of hoarding disorder as a unidimensional construct.
• Acquisition, clutter, and discarding difficulties co-occur strongly, forming a cohesive hoarding phenotype.
• Implications exist for considering acquisition as a specifier in the DSM-5.