Date of Award

Summer 2020

Document Type

Dissertation - Restricted

Degree Name

Doctor of Philosophy (PhD)



First Advisor

Woods, Douglas W.

Second Advisor

Nielson, Kristy A.

Third Advisor

Larson, Christine L.


The emotion regulation (ER) model of trichotillomania (TTM) has spurred the development of the most efficacious treatments available for the highly impairing disorder. The transient nature of gains derived from these treatments, however, indicates the need for advancing this model. This pilot study investigated whether the extended process model of ER (Ochsner & Gross, 2014), which provides a conceptualization of the neurobiological underpinnings of ER, can be used to advance this model by advancing understanding of ER in TTM. Specifically, this study explored the intrinsic functional connectivity (iFC) of regions comprising a cognitive control system (i.e., the dorsolateral prefrontal cortex [PFC], ventrolateral PFC, dorsal posterior medial PFC, and dorsal anterior cingulate cortex) and valuation system (i.e., the amygdala and insula) in adults with and without TTM, as the extended process model of ER suggests these systems may underlie TTM.In total, 6 adults with TTM (M = 24.50 years, SD = 3.50) and 6 without (M = 19.50, SD = 1.38) completed this study. In their first in-person study visit, participants completed several self-report measures and were assessed with multiple clinician-rated measures. Participants underwent resting-state functional magnetic resonance imaging scanning in their second in-person visit.Results showed the participant groups significantly differed on self-reported ER difficulties, but only when self-reported anxiety and depression were not controlled. The participant groups did not significantly differ on iFC between or within the valuation and cognitive control systems, nor did they differ on iFC with any of the regions comprising these systems when anxiety and depression were controlled. However, results showed that, for participants with TTM, iFC between and within the valuation and cognitive control systems significantly correlated with self-reported ER difficulties, self-reported and clinician-rated TTM severity, and clinician-rated TTM impairment.Although this pilot study’s sample size precludes strong conclusions, the present findings suggest iFC between and within the valuation system may be particularly important in TTM pathology and, further, suggest treatments that modify iFC between and within these systems may be beneficial for TTM. Future research should explore this hypothesis. Future research should also continue to explore TTM neural underpinnings.



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