Year of Publication

2014

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Arts and Sciences

Department

Psychology

First Advisor

Dr. Mark T. Fillmore

Abstract

There is growing evidence that acute changes in fundamental mechanisms of impulse control contribute to the transition from social drinking to abusive drinking. One component of impulsivity concerns the ability to inhibit maladaptive behaviors (i.e., inhibitory control). Inhibitory mechanisms are reliably shown to be sensitive to the impairing effects of alcohol, and studies have begun to show that this impairment fails to recover at the same speed as other aspects of behavior. However, the degree to which inhibitory control develops tolerance to alcohol has only been examined under limited conditions. This dissertation consists of three studies examining contexts in which tolerance has been observed for a host of prototypic behaviors, and will compare the degree to which it fails to develop for inhibitory control. Study 1 examined the rate of recovery for inhibitory control compared with other behaviors as blood alcohol concentrations (BACs) declined to zero following a dose of alcohol in 24 social drinkers. Results revealed prolonged alcohol impairment of inhibitory control along the BAC curve, even as BACs approached zero. By contrast, behaviors including reaction time and motor coordination began to show recovery markedly faster, as BACs were still significantly elevated. Study 2 examined the degree to which recent drinking patterns predict acute alcohol impairment from alcohol in a group of 52 drinkers. Recent, heavy consumption predicted less impairment of motor coordination, but bore no relationship to the magnitude of impairment of inhibitory control. Study 3 examined whether increasing the stimulus strength of environmental cues signaling the need to inhibit behavior could reduce alcohol impairment of inhibitory control in 56 participants. Results showed that increasing stimuli strength reduced alcohol impairment of behavioral activation, but actually increased inhibitory failures. Taken together, the findings contribute to the growing body of evidence suggesting that inhibitory control is especially vulnerable to the impairing effects of alcohol compared with other behaviors. Indeed, these studies systematically assessed the pharmacokinetic and environmental factors that contribute to tolerance, indicating that inhibition is disrupted in circumstances under which response activation is unimpaired. The findings have important implications for understanding the behaviorally-disruptive effects of alcohol.

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