Neurocognitive and Dysfunctional Belief Candidate Endophenotypes of Obsessive-Compulsive and Related Disorders

Background: The current dissertation examined neurocognitive and dysfunctional belief candidate endophenotypes (CEs) across the obsessive compulsive spectrum to elucidate general versus specific factors. This study included CEs from two etiological perspectives well established in the literature. Secondary analyses examined several CEs multidimensionally and examined the relationship between CEs and of QOL. Methods: A total of 77 participants took part in this study, divided into four groups; OCD (n = 21), Hoarding Disorder (HD; n = 16), Grooming Disorders which included both Trichotillomania and Excoriation Disorder (GD; n = 18), and control participants (n = 22). Participants completed a clinical interview and battery of neurocognitive tasks and questionnaires. Results: Those with HD performed worse than controls on measures of response inhibition and set-shifting. OCD continued to predict significant variance in number sequencing. Examination of dysfunctional belief CEs revealed specificity of Responsibility/Threat beliefs and Importance/Control of Thoughts beliefs to OCD. Perfectionism/Intolerance of Uncertainty appear to be broad CEs; however, differing specificity emerged depending on the measure utilized to measure the construct. Self-report indecision revealed specificity to OCD and HD. Differing patterns of QOL impairments emerged across the spectrum. A better understanding of CEs specificity has implications for diagnostic classification, etiology, course, and treatment.