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UBC Theses and Dissertations

A study of neurocognition in OCD-affected youth, at-risk siblings, and healthy controls. Negreiros, Juliana


OCD is a neuropsychiatric illness that often begins in childhood, has significant impact on family, academic, occupational, and social functioning. OCD has complex genetic underpinnings, with a 10-fold increased risk among siblings of OCD-affected youth. Attempts to identify OCD vulnerability contributory genes have had suboptimal results partially due to the heterogeneous nature of OCD that prevents the differentiation of external symptoms in genetically homogenous subgroups. Although genetic influences are greater in childhood-onset OCD, most studies have used adult samples. There is increasing interest in determining intermediate markers of brain dysfunction (endophenotypes) that are associated with vulnerability for OCD through neurocognitive assessment. This study examined neurocognition in OCD-affected youth (N=29), in comparison to their siblings (N=18), and healthy controls (N=31), in the areas of executive function, attention, visual memory, intelligence, state anxiety, and OCD symptom severity. It was hypothesized that OCD-affected youth and their siblings would have lower performance on all neurocognitive tasks in comparison to healthy controls, with the exception of attention and visual memory. Only the OCD group would present with behaviour challenges associated with executive dysfunction. There would be no relationship between symptom severity and test performance and state anxiety and test performance in the sample. Analysis of covariance (ANCOVA) and mixed model ANCOVA with family membership as a random factor were used to assess group effects on the outcome variables. OCD-identified youth presented with significant deficits in planning and daily behaviour associated with executive dysfunction in comparison to healthy controls. Siblings demonstrated poorer decision-making when compared to OCD and healthy control participants. No significant group differences were found in other examined neurocognitive areas. Symptom severity was not associated with neurocognitive performance of OCD-affected youth, whereas high state anxiety was associated with poorer decision-making across all groups. Impaired planning has been implicated as a potential endophenotype in OCD, similar to previous adult studies. This study contributes to the limited research on neurocognitive functioning of OCD-affected youth and their siblings, increases awareness about neurocognitive deficits in OCD, and provides information for the advancement in school and clinical interventions and early identification of those at risk for developing OCD.

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