NEUROPSYCHOLOGICAL MEDIATORS OF TREATMENT FOR TRICHOTILLOMANIA: RESPONSE INHIBITION, SET SHIFTING, AND THE ROLE OF

A randomized controlled trial (RCT) has provided evidence for the effectiveness of the Comprehensive Behavioral (ComB Model of Treatment for trichotillomania (TTM; Carlson, et al., 2021). To best understand the ComB treatment and the mechanisms through which it improves TTM symptoms, it is important to identify mediators of treatment effects. Research on the neuropsychology of TTM provides evidence that response inhibition and set shifting are areas of weakness in this population (Odlaug et al., 2013; Slikboer et al., 2013). Symptom improvement through the ComB intervention may be attributable to changes in these cognitive domains. Specifically, ComB aims to help clients reduce hairpulling by teaching them to recognize and resist urges (related to response inhibition) and replace pulling with alternative behaviors (related to set shifting). Research from Odlaug et al. (2012) provides evidence that age at onset may also be a relevant factor to understanding the neuropsychological mechanisms of TTM. The current study used data from an RCT of ComB to examine response inhibition and set shifting as mediating mechanisms of treatment with age of onset as a moderator. Results were nearly all nonsignificant, providing little to no evidence of a relationship between TTM symptoms and response inhibition or set shifting or a moderated mediation of treatment effects. Research on possible subtypes of TTM and frequent comorbidities indicate that these factors may explain inconsistent findings across research examining the neuropsychology of TTM.