Electronic Theses and Dissertations Archive

Date

2026

Document Type

Thesis

Degree Name

Master of Science

Department

Psychology

Committee Chair

Nicholas Simon

Committee Member

Helen Sable

Committee Member

James Murphy

Abstract

Risky decision-making is a feature of mental health disorders such as substance use disorder and schizophrenia and is often linked to alterations in the brain’s cannabinoid system. However, how cannabinoid signaling regulates punishment-based risky decision-making remains unclear. To address this question, we assessed the effects of multiple cannabinoid drugs on risky decision-making in male and female Long-Evans rats using the Risky Decision-Making Task (RDT). Following training, rats received varying doses of Δ⁹-tetrahydrocannabinol (THC; CB1/CB2 receptor partial agonist), ACEA (CB1 receptor agonist), Rimonabant (CB1 receptor inverse agonist), and AA-5-HT (FAAH inhibitor that increases endocannabinoid tone). THC did not alter risky choice overall but produced sex-dependent effects, with high-dose THC reducing risky decision-making and impairing sensitivity to changing task contingencies in males but not females. Indirect enhancement of endocannabinoid signaling with AA-5-HT did not significantly affect risky choice in either sex. Direct CB1 receptor activation with ACEA also did not alter risky decision-making but increased latency to select the safe option in females at the highest dose. In contrast, blocking CB1 receptors with Rimonabant reduced risky choice across doses, with effects largely driven by females, particularly at the highest dose, while males showed only modest reductions. Rimonabant also increased trial omissions selectively in males, suggesting sex-specific alterations in task engagement at higher doses. Across experiments, control measures of task engagement, motivation and decision speed including omissions and response latency were largely unchanged by drug administration, indicating that most behavioral effects were not attributable to general motor impairment or reduced motivation. Additionally, shock threshold testing revealed that neither high-dose THC nor Rimonabant altered sensitivity to foot shock, indicating that changes in risky choice were not driven by altered perception of punishment. These findings demonstrate that cannabinoid modulation of punishment-based risky decision-making depends on both the mechanism of receptor manipulation and biological sex. Collectively, the results demonstrate that CB1 receptor signaling plays a critical role in cost–benefit evaluation under threat and highlight the importance of sex-specific considerations when evaluating the cognitive effects of cannabis and cannabinoid-based therapeutics.

Comments

Data is provided by the student.

Library Comment

Dissertation or thesis originally submitted to ProQuest/Clarivate.

Notes

Open Access

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