Date of Award

2009

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Psychology

First Advisor

Potter, Alexandra

Abstract

ADHD is one of the most common childhood psychiatric disorders affecting 3- 5% of all children. Between 50 and 80% of those diagnosed with ADHD in childhood will show symptoms that persist into adolescence and adulthood. ADHD is characterized by developmentally excessive activity, impulsivity, inattention, and disorganized, off-task behaviors. A high propensity for risk taking is seen in ADHD and is related to negative outcomes such as job failure, accidents and injuries, and substance use. In an attempt to better understand the behavioral and cognitive deficits associated with ADHD, several neuropsychological models have been proposed. We suggest that those models may be used to learn about risk taking propensity in ADHD. Individuals with ADHD smoke cigarettes at twice the rate of individuals who do not have this diagnosis, and they have greater difficulty quitting. And smokers score higher on a behavioral task of risk taking propensity than non-smokers. The strong association between ADHD and cigarette smoking and the known effects of nicotine on cognition has lead to interest in the role of cholinergic function in ADHD cognitive deficits. Previous work demonstrates that acute nicotine improves behavioral inhibition, working memory, and recognition memory in ADHD. This study examined the acute effects of nicotine on risk taking in non-smoking young adults with ADHD-Combined Type and healthy controls. This single-dose, acute, double blind study assessed the effects of transdermal nicotine and placebo on 26 non-smoking young adults (15 healthy controls and 11 ADHD-C). Participants received acute nicotine (7 mg patch for 45 minutes) and placebo on separate days. The Balloon Analogue Risk Task (BART) was used to assess risk taking propensity. Behavioral ratings were completed daily by each subject and by the blinded investigator. Vital sign data were collected at 30 minute intervals throughout each study day. There were no group differences or interaction of drug and group between the ADHD and control group on risk taking propensity. However, using a median split to identify subjects as either high or low in baseline risk taking there was a significant (p<.05) Drug by Group interaction with nicotine reducing risk taking in high risk taking subjects and increasing risk taking in the low risk taking subjects. These findings are consistent with a large body of research demonstrating ratedependent effects of nicotine on behavior, cognition and mood. Nicotine appears to modulate risk-taking in both high and low risk-taking subjects consistent with cholinergic modulation of behavioral decision making.

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