Validation of a Behavioral Measure of Acquiring and Discarding in Hoarding Disorder.

Behavioral assessment is an important component of evidence-based assessment and treatment in anxiety and related disorders. The purpose of the current study was to validate a behavioral measure of difficulty discarding and acquiring, the core features of hoarding disorder (HD). Seventy-eight patients with a primary diagnosis of HD completed a computerized acquiring and discarding task; the task consisted of making simulated decisions about acquiring and discarding items of varying monetary value. A subset of patients (n = 42) went on to receive cognitive behavioral therapy (CBT) for HD and completed the computer tasks again after treatment. An additional 30 age- and sex-matched healthy control participants (HCs) also completed the acquiring and discarding tasks. Results showed that HD patients saved and acquired more items than the HC group, and had longer response times during the tasks. In support of the convergent validity of the tasks, item decisions and reaction times were positively correlated with established measures of HD symptoms. Among treatment completers, items saved and acquired and response times decreased from pre- to post-CBT, suggesting that the tasks were sensitive to detect treatment-related changes in difficulty discarding and acquiring behaviors. The findings support the validity of the discarding and acquiring tasks in measuring HD symptoms, and are discussed in terms of the potential advantages of behavioral measures in HD treatment and research.