Acute Behavioural Tolerance to the Effect of Alcohol on Information Processing, Response Inhibition, and Subjective Intoxication

Abstract

Acute tolerance is a rapid decrease in the effect of alcohol relative to the size of the dose. This thesis is comprised of four manuscripts (Comley & Dry, 2020a; Comley & Dry, 2020b; Comley & Dry, under review-a; Comley & Dry, under review-b), each addresses a limitation in our understanding of the effect. The aims of the literature review (Comley & Dry, 2020a) were to examine paradigms for observing acute tolerance, identify what evidence has been found, identify domains of behaviour where it occurs, and ascertain which conditions influence it. Seven different research paradigms were identified. The effect was found to be prevalent, but not uniform across different behavioural measures. The evident uncertainty around which measures are susceptible to acute tolerance prompted the undertaking of two experimental studies. The first study (Comley & Dry, 2020b) examined acute tolerance in subjective intoxication, and in two cognitive domains: information processing speed measured using the Inspection Time Task, and response inhibition measured using the Sustained Attention to Response Task. An acute tolerance effect was found in ratings of subjective intoxication and Inspection Time Task performance. The second study (Comley & Dry, under review-a) investigated acute tolerance in subjective intoxication, response inhibition measured using the Stop-Signal Paradigm, and executive and psychomotor speed measured using a Multiple-Choice Reaction Time task. This paper also examined the influence of dose-size on acute tolerance. An acute tolerance effect was only seen in ratings of subjective intoxication, and only under the higher dose. The fourth paper (Comley & Dry, under review-b) reports an additional examination of the ratings of subjective intoxication from the second study. Acute tolerance to subjective intoxication was examined using three different paradigms identified in the literature review. In all three paradigms, an acute tolerance effect was observed in the high dose condition, but not in the low dose condition.