Randomized waitlist-controlled trial of buried in treasures facilitated support groups and in-home uncluttering (BIT+) for hoarding disorder

The Buried in Treasures (BIT) workshop is a promising treatment for hoarding disorder (HD), though many participants struggle with home uncluttering. This randomized waitlist-controlled trial investigated the efficacy of a version of BIT, augmented with in-home uncluttering practice (BIT+). Adults (N = 41) with hoarding disorder were recruited from the community and randomly assigned to BIT+ or waitlist. BIT+ consisted of 16 sessions of the BIT workshop and 10 uncluttering home visits over 18 weeks. Outcome measures included the Saving Inventory-Revised (self-report) and the Clutter Image Rating Scale (self and independent evaluator rated). Between group repeated measures analyses using general linear modeling examined the effect of BIT+ vs waitlist control on hoarding symptoms after 18 weeks. Within group analyses examined pre-post effects for all BIT+ participants combined after 18 weeks. After 18 weeks, BIT+ participants benefited significantly more than waitlist controls on hoarding severity with large effect size (Cohen's d = 1.5, p