The Effects of Acute Alcohol Intoxication and Alcohol Hangover on Cognitive and Driving Performance: A Randomized Control Trial

Alcohol is the intervention being assessed across two study Arms. Alcohol will be consumed twice in Arm 1, once in Arm 2a and once in Arm 2b. Overall, participants will attend the testing site on 7 occasions, 6 for testing and 1 screening. Arm 1: This arm involves 3 test sessions where 0.0 g/kg (placebo), 0.6 g/kg and 0.85 g/kg of alcohol will be administered. 2 of these visits will coincide with Arm 2a. This is as follows: i) Arm 1 placebo (0.0 g/kg), followed by Arm 2a (no alcohol administered) ii) Arm 1 involving 0.6 g/kg (no association to Arm 2a) iii) Arm 1 involving 0.85 g/kg, followed by Arm 2a where additional alcohol is administered up to 1.3 g/kg (accounting for alcohol already consumed). Arm 1 visits will be randomized and commence between 4-6 pm. Alcohol will be Absolut brand vodka mixed with original black label orange juice. Participants are allocated 20 minutes to consume alcohol with the exception of the Arm 2a 1.3 g/kg condition where extra time is allowed (see below). Alcohol will be served by a research assistant (with responsible service of alcohol certification), at the instruction of the principle investigator. Alcohol administration will also be supervised by a research nurse. A research assistant and the research nurse will be present to monitor adherence to the intervention. Each visit will separated by no less than 5 days and no more than 14 days. Arm 2a: This Arm involves 2 test sessions: no alcohol and 1.3 g/kg alcohol. The 2 visits follow the Arm 1 visits described above. Participants are allowed up to 2 hours to consume extra beverages in 1.3 g/kg condition with a mandatory 20 minute absorption period to follow. Alcohol will be served by a research assistant. Participants will be monitored by a research assistant and research nurse and are not obliged to consume all allocated beverages. Following administration of the intervention participants will be sent home for the evening (by taxi) before returning to the test site the following morning for the non-hangover (no alcohol) and hangover (1.3 g/kg) test sessions. These sessions will be between 8-11 hrs after alcohol consumption and will be scheduled between 7-11 am. Arm 2b: This Arm occurs after the completion of Arm 1 and 2a and involves 2 visits: no hangover and hangover. Participants will consume alcohol on a normal night out unrestricted, and attend testing the following morning when experiencing a hangover. The no hangover session will follow a night of alcohol abstinence. Test sessions will be scheduled between 7-11 am. Participants will contacted the morning of the test session to ensure they are attending (both sessions) and are feeling well enough to attend (hangover session only). Participant compliance will also be monitored by self-report assessments of hangover severity and BAC readings of 0.00%. Test visits will be randomized and no less than 5 days and no more than 14 days apart.