Rationale. Hoarding disorder (HD) is an obsessive-compulsive spectrum disorder characterized by urges to save objects, difficulty discarding current possessions, and excessive clutter levels in the home. Research suggests that HD is progressive, functionally and cognitively debilitating, socially isolating, and may affect up to 6% of the population. Exposure therapy is the gold standard treatment for obsessive-compulsive spectrum disorders, and exposure-based psychotherapy has been found to be effective in the treatment of HD. No studies of HD have yet utilized a standardized exposure task. The establishment of a standardized exposure task for HD would allow for a uniform way to objectively assess treatment response. The objective of this project was to explore the feasibility and validity of a standardized exposure task for HD by utilizing subjective, physiological, and behavioral assessments of fear response (i.e., response variables) during an exposure-related sorting task.
Design. This study utilized the baseline assessment data from 60 participants enrolled in an ongoing study comparing outcomes for two exposure-based treatments for HD. During the standardized exposure task, all participants sorted items they brought from home and for each item they made the decision to either discard or keep the item. In order to standardize the task, assessors used a script when assisting participants in gathering their items and encouraged participants to gather items from areas of the home that were more difficult to sort (e.g., areas with visible excessive clutter). Assessors also used a script when administering the task to increase the standardization. Throughout the task, participants’ heart rate and subjective units of distress (SUDS) were recorded at regular intervals. The number of exposure items sorted and the percent of items discarded were recorded as behavioral indicators of approach-orientation to the task. Aim 1: Demonstrate the feasibility and construct validity of a standardized exposure task for hoarding through the engagement and completion of a baseline standardized exposure task in which HD patients are asked to sort objects from their homes. Aim 2: Using Pearson correlations, explore the associations of objective and subjective baseline hoarding severity with baseline exposure task response variables.
Results. Aim 1: HD patients were able to engage in the standardized exposure task and sorted items brought from their home until either all items were sorted or the allotted time had elapsed. Heart rate data was only successfully collected from 43% of participants, largely due to assessor error. Only 58% of participants reported elevated SUDS ratings for at least a portion of the task. On average, participants reported that the task was “somewhat similar” to when they sort at home. Participants who reported higher SUDS at the end of the task were more likely to report that the task was similar to sorting at home. A self-report measure of difficulty discarding was significantly correlated with peak SUDS ratings during the task.
Aim 2: Participants’ subjective initial fear activation (i.e., their peak SUDS score) during the sorting task was significantly correlated with their subjective within-session habituation (i.e., the change from their peak SUDS score to their final SUDS score); however, participants’ physiological initial fear activation (i.e., their peak HR) during the sorting task was not significantly correlated with their physiological within-session habituation (i.e., the change from their peak HR to their final HR). Assessor ratings of clutter were not significantly correlated with any of the task response variables. Participants who self-reported higher levels of excessive acquisition reported higher peak SUDS and discarded a lower percentage of items during the task.
Conclusions. Results suggest that the developed standardized exposure task for HD may have incremental validity in the assessment of hoarding symptomology, but further testing is needed in order to determine if the task is sensitive to change in response to treatment. Once the standardized exposure task is fully validated, clinicians treating HD should consider using this task to assess behavioral change during treatment as well as changes in physiological and subjective distress during sorting.