Advisor(s)
Adrienne Lahti
Committee Member(s)
David Knight
Edwin Cook Iii
Kristina Visscher
Sylvie Mrug
School
College of Arts and Sciences
Document Type
Dissertation
Department (new version)
Psychology
Date of Award
9-11-2025
Abstract
Schizophrenia is a complex psychiatric disorder characterized by hallucinations, delusions, disorganized thinking, and abnormalities in emotional expression, social interaction, and motivation. Cognitive deficits and alterations in perception are core features of psychosis spectrum disorders, though the neurobiological bases of these impairments are not thoroughly understood. Examination of the structures responsible for cognition, along with how their connectivity and neurochemistry are altered in psychosis, is crucial to understanding and treating schizophrenia. Gamma-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the central nervous system and plays a crucial role in the regulation of neuronal activity. Evidence from animal models and postmortem studies have implicated alterations in GABAergic neurotransmission in schizophrenia, though the degree to which this has been demonstrated in vivo has been limited and varies based on study methodology. The anterior cingulate cortex (ACC) is a region of the limbic system connected to the frontal and parietal lobes, and is therefore involved in processing emotional and motivational stimuli and communicating the salience of that information to the rest of the brain. The ACC has been implicated in schizophrenia, showing abnormal activation when compared to healthy controls (HC), as well as altered functional and structural connectivity. Functional magnetic resonance imaging (fMRI) studies have found disruptions in key brain networks such as the salience and the default mode networks, where functional connectivity is reduced in patients with psychosis spectrum disorders. Similarly, diffusion-weighted imaging studies in schizophrenia have found abnormalities in structure, where measures of white matter tract organization and integrity are altered in regions such as the cingulum bundle. Here, we used multimodal approaches to investigate the neurobiological bases of differences in psychosis spectrum disorders. We measured GABA in the ACC, longitudinally and at baseline, along with functional connectivity and white matter integrity, compared between antipsychotic medication-naïve patients with first episode psychosis (FEP) and HC. We found lower GABA levels in FEP compared to HC. Further, the relationships between GABA and both functional connectivity and white matter integrity found in HC were altered or absent in FEP. These findings add to the growing literature implicating GABA’s role in psychosis spectrum disorders.
ProQuest ID
Recommended Citation
Samson, Genelle Dano, "An Analysis Of Gamma-Aminobutyric Acid Levels With Structural And Functional Connectivity In Antipsychotic Medication-Naïve First Episode Psychosis Patients" (2025). All ETDs from UAB. 7449.
https://digitalcommons.library.uab.edu/etd-collection/7449
