Abstract

The limbic system is hypothesized to play a critical role in pathophysiology of schizophrenia, with abnormalities thought to contribute to the expression of various aspects of the cognitive deficits and clinical symptoms. Psychosis is understood as highly heritable and family members, specifically non-affected siblings, while not displaying overt signs of the disorder, often exhibit features similar to those observed in patients, though to a lesser degree. The overarching aim of this project was to investigate the integrity of limbic circuitry in a sample of patients with schizophrenia and their non-affected siblings and examine its potential relationship with various clinical features of the illness. Cortical thickness of the entorhinal, parahippocampal, cingulate, and orbitofrontal cortices; as well as subcortical surface shape of the hippocampus and amygdala were the focus of this study. Findings from this study reveal relative similarity in limbic integrity between individuals with schizophrenia and theirnon-affected siblings, which are both disparate from healthy individuals. This suggests aspects of the neurobiological underpinnings of psychosis, particularly limbic regions, are genetically influenced regardless of symptom expression and are latent features in non-affected family members. Relationships between positive symptomatology and shape abnormalities of subcortical structures suggest a potential substrate for clinical characteristics in psychosis not evident in non-ill siblings.

Degree

College and Department

Family, Home, and Social Sciences; Psychology

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