The present study examined the effects of alcohol on the ability to execute and inhibit behavior in a context in which preliminary information signaled the likelihood that a response should be executed or suppressed. Social drinkers (N = 12) performed a cued go/no-go task that required quick responses to go targets and suppression of responses to no-go targets. Performance was tested under 3 doses of alcohol: 0.65 g/kg, 0.45 g/kg, and 0.0 g/kg (placebo). Alcohol had no effect on inhibition and execution when cues correctly signaled these actions. By contrast, alcohol impaired inhibition and execution in a dose-dependent manner when cues incorrectly signaled actions. These findings are consistent with a resource limitation account of alcohol impairment.

Background-There has been a dramatic rise in the consumption of alcohol mixed with energy drinks (AmED) in young people. AmEDs have been implicated in risky drinking practices and greater accidents and injuries have been associated with their consumption. Despite the increased popularity of these beverages (e.g., Red Bull and vodka), there is little laboratory research examining how the effects of AmED differ from alcohol alone. This experiment was designed to investigate if the consumption of AmED alters neurocognitive and subjective measures of intoxication compared with the consumption of alcohol alone.

Alcoholic drink preferences in college students have made an interesting shift recently, with trends in consumption leaning toward caffeinated alcohol in various forms (e.g., Red Bull and vodka or caffeinated beers such as Anheuser-Busch's B-to-the-E). Despite the dramatic rise in popularity of these beverages, little research has examined the combined effects of alcohol and caffeine, which is problematic for adequately informing the public about the risk or lack thereof of these drinks. The purpose of this study was to directly investigate the acute effects of alcohol and caffeine, alone and in combination, on well-validated measures of cognitive performance and subjective intoxication in social drinkers. Participants (N = 12) performed a psychological refractory period task that measured dual-task interference as the prolonged reaction time to complete the 2nd of 2 tasks performed in close temporal sequence. Performance was tested under 2 active doses and 1 placebo dose of caffeine (0.0 mg/kg, 2.0 mg/kg, and 4.0 mg/kg) in combination with 1 active dose and 1 placebo dose of alcohol (0.0 g/kg and 0.65 g/kg). As expected, alcohol impaired task performance by increasing dual-task interference and increasing errors. The coadministration of caffeine counteracted the effects of alcohol on interference but had no effect on the degree to which alcohol increased errors. Subjective measures of intoxication showed that coadministration of caffeine with alcohol reduced participants' perceptions of alcohol intoxication compared with administration of alcohol alone. The results highlight the complexity of drug interactions between alcohol and caffeine.

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