Abstract

Obsessive-compulsive disorder (OCD) is an often-debilitating psychiatric disorder involving a pattern of obsessive thoughts and compensatory compulsions. Symptoms tend to be chronic, leading to substantial emotional burden and significant impairment across multiple domains of daily functioning. Previous research has identified some consistency in the brain regions implicated in OCD. In particular, cortico-striato-thalamo-cortical (CSTC) circuitry has been linked to behavioral features commonly observed in OCD. Moreover, some studies suggest that distinct patterns of brain activation and functional connectivity may be associated with different OCD symptom dimensions, though findings have not been consistent. One symptom dimension of OCD (scrupulosity) is characterized by religious and/or moral obsessions and compulsions. Scrupulosity remains understudied, is highly heterogeneous in presentation, and has been associated with poorer treatment outcomes. Focused investigation of scrupulosity is therefore needed to improve understanding of its neural circuitry and, ultimately, to inform more effective treatment approaches. The present dissertation aims to characterize the brain circuitry involved in scrupulosity. Secondary to this goal, we aim to improve the neurobiological sensitivity of our methods by accounting for individual variability in functional brain organization, as well as the religious and cultural context of our participants. Study 1 identifies the pattern of brain activation that is associated with experiencing the distressing thoughts and feelings associated with scrupulosity. Study 2 then examines the functional connectivity between the brain regions that demonstrated task-evoked differences in the previous study. Finally, Study 3 examines the neural circuitry associated with OCD symptoms acquired after focal brain injury and contrasts it with the results from the previous studies. Taken together, these studies use converging neuroimaging approaches to elucidate the brain circuits involved in scrupulosity.

Degree

PhD

College and Department

Family, Home, and Social Sciences; Psychology

Rights

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