The Subjective Physiological, Psychological, and Behavioural Risk-Taking Consequences of Alcohol and Energy Drink Co-Ingestion

Background: The increasingly popular practice amongst adolescents and young adults of consuming alcohol mixed with energy drinks (AmED) has raised concern regarding potential increases in maladaptive drinking practices, negative psychological and physiological intoxication side-effects, and risky behavioural outcomes. Comparison of user types has revealed that AmED users report engaging in more risk-taking behaviour relative to alcohol users. However, the comparative likelihood of risk-taking according to session type (i.e., AmED versus alcohol session) remains relatively unknown. Thus, the current study was designed with the aim of establishing the subjective physiological, psychological, and behavioural risk-taking outcomes of AmED consumption relative to alcohol consumption for AmED users drawn from the community. Method: Between May and June 2011, 403 Australians aged 18-35 who had consumed AmED and alcohol only in the preceding six months completed a 10-30 minute online survey about their use of these substances. Results: Despite participants consuming a significantly greater quantity of alcohol in AmED sessions compared to alcohol sessions, the odds of participants experiencing disinhibition and engaging in 26 risk behaviours were significantly lower during AmED sessions relative to alcohol sessions. Similarly, the odds of experiencing several physiological (i.e., speech and walking difficulties, nausea, and slurred speech) and psychological (i.e., confusion, exhaustion, sadness) sedation outcomes were less during AmED sessions compared to alcohol sessions. However, the odds of enduring physiological (i.e., heart palpitations, sleep difficulties, agitation, tremors, jolt and crash episodes, and increased speech speed) and psychological (i.e., irritability, tension) outcomes potentially related to over-stimulation were significantly greater during AmED sessions than alcohol sessions. Conclusions: Co-ingestion may provide a double-edged effect. The increased stimulation from energy drinks may negate some intoxication-related sedation side-effects by increasing alertness. However, it could also lead to negative physiological side-effects associated with over-stimulation. Notwithstanding any stimulatory effects of energy drinks, risk and negative effects of excessive alcohol consumption were present in both session types. However, the odds of engaging in risk-taking were less during AmED sessions relative to alcohol sessions. Objective measurement of behavioural risk-taking via laboratory-based measures could confirm the causal relationship between AmED and risk-taking.