Date of Award

12-2007

Degree Name

Doctor of Philosophy

Department

Psychology

First Advisor

Dr. Lisa E. Baker

Second Advisor

Dr. Alan D. Poling

Third Advisor

Dr. Amy Naugle

Fourth Advisor

Dr. Herbert Y. Meltzer

Abstract

Research has shown a differential prevalence of smoking in the schizophrenic population compared to other psychiatric and non-diagnosed populations. The three most commonly investigated reasons for this differential prevalence in schizophrenics are: the self-medication hypothesis, side effects hypothesis, and sociological hypothesis. The self-medication hypothesis which proposes that schizophrenics smoke at a higher rate to ameliorate cognitive deficits is the most substantiated by the research. Of current interest is the possible role of nicotine in improving performance on vigilance and verbal memory, the two areas shown to be most related to impaired social functioning in schizophrenics. It is difficult to make comparisons among the existing research investigating the effects of nicotine on verbal memory and vigilance in non-diagnosed populations due to the use of differing nicotine delivery mechanisms, populations, and assessment tools. The current study implemented standardized and psychometrically sound assessments of verbal memory (immediate and delayed) and vigilance to assess in smokers the impact of nicotine via the participants' normal smoking behaviors. Following acute abstinence (≥ 6 hrs) 15 non-diagnosed smokers completed the Conner's Continuous Performance Test (CPT) and Rey Auditory Learning Test (RVLT) using a counterbalanced design. Results of the repeated measures analysis revealed no statistically significant effect of nicotine. Subsequent covariate analysis revealed a significant effect of nicotine on RVLT total score when controlling for sex and number of cigarettes per day. Likewise covariate analysis revealed a significant effect of nicotine on the CPT overall index and hit rate block change sub-measures when controlling for age. An examination of trend lines revealed a consistent decrease in performance on all CPT sub-measures and on RVLT measures related to memory storage as a result of nicotine abstinence, while nicotine abstinence improved performance on RVLT measures of memory storage. While it is difficult to draw conclusions from the current study, a less robust finding in a non-diagnosed population than is typically found in diagnosed populations might be suggestive of different reasons for smoking between the populations.

Access Setting

Dissertation-Open Access

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