Electronic Theses and Dissertations

Date

2024

Document Type

Thesis

Degree Name

Master of Science

Department

Psychology

Committee Chair

Helen Sable

Committee Member

Deranda Lester

Committee Member

James Whelan

Abstract

The perception that cannabis (i.e., marijuana) use produces little to no harm is widespread, with about 70% of both pregnant and nonpregnant women believing there is slight or no risk associated with using cannabis once or twice a week. However, perinatal exposure to cannabis has been linked to externalizing behaviors in offspring, including impulsivity, hyperactivity, and substance use – behaviors associated with externalizing disorders including attention-deficit hyperactivity disorder (ADHD). In preclinical research, most studies focus on exposure to the psychoactive constituent of cannabis, delta-9-tetrahydrocannabinol (∆9-THC). ∆9-THC is lipophilic so it can cross the placental barrier and is secreted in maternal milk, thereby exposing the fetus/neonate. Preclinical data on the effects of perinatal ∆9-THC exposure on impulsive behavior is extremely limited. Therefore, we examined whether perinatal exposure to 5.0 mg/kg/day ∆9-THC or an equal volume of vehicle increased impulsivity in adult offspring. We used a differential reinforcement of low rates (DRL) operant task to measure impulsive action where the rat had to press a lever to start a trial but wait a prespecified amount of time before pressing the same lever again to earn a food reinforcer. ∆9-THC-exposed rats earned fewer reinforcers and exhibited a higher proportion of non-reinforced IRT pause responses between 2.5 – 15.0 sec, as well as a lower proportion of reinforced IRT responses greater than 15.0 sec, indicative of impulsivity. Surprisingly, they also appeared to exhibit decreased motivation, which is also frequently observed in ADHD individuals. These results validate epidemiological findings demonstrating an increase in externalizing behavior following perinatal cannabis exposure, but also suggest perinatal cannabis exposure may alter affective behavior

Comments

Data is provided by the student.”

Library Comment

Dissertation or thesis originally submitted to ProQuest.

Notes

Embargoed unitl 3/29/2026

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Available for download on Sunday, March 29, 2026

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