Changes in Neural Activity Following a Randomized Trial of Cognitive Behavioral Therapy for Hoarding Disorder

Objective: Cognitive behavioral therapy (CBT) is efficacious for hoarding disorder (HD), though results are modest. HD patients show an increase in activity in the dorsal anterior cingulate cortex (dACC) when making decisions. The aim of this study is to determine whether CBT's benefits follow improvements in dACC dysfunction or abnormalities previously identified in other brain regions. Method: In this randomized clinical trial of 64 treatment-seeking HD patients, patients received group CBT, delivered weekly for 16 weeks, versus wait list. Functional magnetic resonance imaging was used to examine neural activity during simulated decisions about whether to acquire and discard objects. Results: During acquiring decisions, activity decreased in several regions, including right dorsolateral prefrontal, right anterior intraparietal area, both right and left medial intraparietal areas, left and right amygdala, and left accumbens. During discarding decisions, activity decreased in right and left dorsolateral prefrontal, right and left rostral cingulate, left anterior ventral insular cortex, and right medial intraparietal areas. None of the a priori brain parcels of interest significantly mediated symptom reduction. Moderation effects were found for left rostral cingulate, right and left caudal cingulate, and left medial intraparietal parcels. Conclusions: Therapeutic benefits of CBT for HD do not appear to be mediated by changes in dACC activation. However, pretreatment dACC activation predicts outcome. Findings suggest the need to re-evaluate emerging neurobiological models of HD and our understanding of how CBT affects the brain in HD, and perhaps shift focuses to new neural target discovery and target engagement trials.