Doctor of Philosophy (PhD)



Document Type



Research has indicated that individuals who are dependent on substances may have decision-making deficits that contribute to their continued substance use. Previous studies have shown that substance-dependent individuals focus more on the immediate rather than the delayed consequences of their actions, and more rapidly discount rewards that are available after a delay than individuals without a history of substance dependence. The present study compared the performance of four groups of individuals on the Gambling Task and the Delayed Discounting Task. The groups were (a) heavy smokers with comorbid substance dependence, (b) heavy smokers with no history of substance dependence, (c) substance dependent never smokers, and (d) never smokers with no history of substance dependence. Analysis revealed a main effect of substance use disorder status, such that individuals who were dependent on substances other than nicotine achieved lower net scores on the Gambling Task than those with no history of substance dependence (p = .05). A significant sex by substance use disorder status interaction was also identified (p = .01). Unexpectedly, no differences in Gambling Task performance were found between smokers and non-smokers. However, individuals who smoked and/or were dependent on another substance discounted delayed rewards on the Delay Discounting Task more rapidly than individuals with no history of smoking or other substance dependence (all p's < .05), and no differences in the performance of heavy smokers and substance-dependent individuals were found. Overall, findings indicate that smoking status may impact performance on the Delay Discounting Task, but does not impact Gambling Task performance. Although no sex differences in performance were identified on the Delayed Discounting Task, performance on the Gambling Task differed between men and women.



Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Amy L. Copeland



Included in

Psychology Commons