Award Date

1-1-2007

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Psychology

First Committee Member

Douglas Ferraro

Number of Pages

229

Abstract

Previous research indicates that ecstasy users exhibit deficits of verbal learning and memory. This research has not considered polydrug use in ecstasy users, especially marijuana. Marijuana is an important confound because 90 percent of ecstasy users also use marijuana. Several studies have suggested that marijuana use alters verbal memory functioning; consequently, it is difficult to ascertain whether the observed memory deficits in ecstasy users are attributable to ecstasy, marijuana, or other drug use. The present study examined the effects of marijuana and ecstasy on verbal memory function. Marijuana use was accounted for by recruiting concurrent ecstasy-marijuana users' and ecstasy-naive marijuana-only users. Furthermore, the extent of marijuana use was controlled for in the combined ecstasy-marijuana and marijuana-only groups by assigning marijuana users to either the marijuana light or marijuana heavy experimental groups. Recent animal findings suggest that at low frequencies marijuana may exert neuroprotective effects against ecstasy-induced neurotoxicity. Alternatively, other animal findings have demonstrated negative synergistic effects between ecstasy and marijuana and working memory performance. Polydrug use was controlled for by restricting other drug use to not more than 15 occasions. Based upon responses to a drug use history questionnaire, 109 students were retrospectively assigned to one of five groups: marijuana-only heavy users, marijuana-only light users, ecstasy-marijuana heavy users, ecstasy-marijuana light users, and non-drug using controls. Participants were matched for age, gender, education, and intelligence as measured by the Wechsler Adult Intelligence Scale, Third Edition. Verbal learning and memory performance was assessed using the Auditory Verbal Learning Test (AVLT) (Rey, 1964; Schmidt, 1996). The Biber Figure Learning Test-Extended version (BFLT-E) was administered during the 20-minute delay of the AVLT. AVLT performance was compared between the two marijuana-only groups and the controls to determine the impact of marijuana use on mnemonic function. The marijuana-only user groups were compared with the ecstasy-marijuana groups to evaluate the effects of ecstasy on verbal memory. Overall, findings in the present study suggest that marijuana use more than ecstasy were associated with AVLT. Additionally, drug use other than ecstasy and marijuana explained some of the impairment observed on the AVLT and even more so for BFLT-E performance.

Keywords

Auditory; Concomitant; Ecstasy; Ecstasy And Polydrug Use; Effects; Learning And Memory In Ecstasy Users; MDMA-thc Interaction; Marijuana; Memory; Performance; Polydrug Use; Verbal Learning; Verbal Memory In Marijuana Users; Verbal Learning

Controlled Subject

Cognitive psychology; Clinical psychology

File Format

pdf

File Size

4218.88 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

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