Cognitive impairment following consumption of alcohol with and without energy drinks

The aim of the present study was to assess the relative effects of alcohol mixed with energy drink (AmED) versus alcohol alone on cognitive performance across the ascending and descending breath alcohol concentration (BrAC) limb using doses similar to real-world energy drink (ED) intake in AmED drinking sessions. Using a single-blind, placebo-controlled, crossover design, 19 participants completed four sessions where they received: (i) placebo, (ii) alcohol, (iii) alcohol and 500 ml ED, and (iii) alcohol and 750 ml ED. Performance on measures of information processing (DigitSymbol Substitution Task, Inspection Time Task), psychomotor function (Compensatory Tracking Task), and response inhibition (Stop-Signal Task) was assessed at ~0.05% ascending breath alcohol concentration (BrAC), ~0.08% peak BrAC, and 0.05% descending BrAC. The SST and ITT showed no differential effect of AmED versus alcohol. Moderate magnitude improvements in alcohol-induced impairment of CTT and DSST performance were observed after AmED versus alcohol at ~0.050% descending target BrAC. A moderate magnitude decrease in DSST errors was also observed after AmED relative to alcohol at ~0.050% ascending target BrAC. These results indicate that changes in cognitive function after AmED administration may be dependent on the degree of intoxication, BrAC curve limb, and ED volume. Co-administration of ED doses which matched (500 ml) and exceeded (500 ml) maximum daily intake guidelines with alcohol decreased impairment of psychomotor function and global information processing after alcohol consumption. These results cannot be necessarily interpreted to suggest that people are less impaired after AmED, as behaviour is the result of coordination of multiple cognitive functions, and reduced impairment on one aspect of cognition may not translate into global improvements