Electronic Theses and Dissertations Archive

Date

2026

Document Type

Thesis

Degree Name

Master of Science

Department

Psychology

Committee Chair

Nicholas Simon

Committee Member

Deranda Lester

Committee Member

James Murphy

Abstract

Schizophrenia is a debilitating mental illness that impacts millions of individuals worldwide. While positive and negative symptoms have been well-characterized for decades, cognitive deficits are emerging as one of the strongest predictors of poor disease outcome. One such area of cognition in which individuals with schizophrenia appear to struggle is decision-making under risk of punishment. To disentangle the relationship between schizophrenia, antipsychotic treatment, and risky decision-making, I conducted a series of experiments using Long-Evans rats trained in the Risky Decision-making Task. First, I examined the effects of the antipsychotic risperidone on risky decision-making both in the context of daily use and acute effects. These experiments revealed that risperidone reduces risky decision-making in females only at therapeutic doses, and decreases it in both sexes at a very high dose, with females showing signs of substantial motivational disruption at all doses examined. This prompted us to examine appetitive motivation in the Progressive Ratio task, revealing that risperidone induces a motivational deficit in both sexes, with this effect being more pronounced in females. I also modeled a psychosis-like state using the NMDA antagonist MK-801, which appeared to increase risky decision-making in males only, and the 5-HT2A agonist DOI, which reduced risky decision-making. Lastly, I modeled antipsychotic treatment in schizophrenia by jointly administering risperidone with each psychotomimetic drug, which revealed a true impairment to risky decision-making.

Comments

Data is provided by the student.

Library Comment

Dissertation or thesis originally submitted to ProQuest/Clarivate.

Notes

Embargoed until 2027-04-06

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Available for download on Tuesday, April 06, 2027

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