In 2016, the Alcohol Hangover Research Group defined the alcohol hangover as “the combination of mental and physical symptoms experienced the day after a single episode of heavy drinking, starting when blood alcohol concentration (BAC) approaches zero”. In the light of new findings and evidence, we carefully reviewed the different components of that definition. Several studies demonstrated that alcohol hangovers are not limited to heavy drinking occasions. Instead, data from both student and non-student samples revealed that at a group level, alcohol hangover may occur at much lower BAC levels than previously thought. Regression analysis further revealed that for individual drinkers, the occurrence of hangovers is more likely when subjects consume more alcohol than they usually do. However, hangovers may also occur at a drinker’s usual BAC, and in some cases even at lower BAC (e.g. in case of illness). We also carefully reviewed and modified other parts of the definition. Finally, hangovers are not necessarily limited to the ‘next day’. They can start at any time of day or night, whenever BAC approaches zero after a single dinking occasion. This may also be on the same day as the drinking occasion (e.g. when drinking in, or until the morning and subsequently having a hangover in the afternoon or evening). To better reflect the new insights and sharpen the description of the concept, we hereby propose to update the definition of the alcohol hangover as follows: “The alcohol hangover refers to the combination of negative mental and physical symptoms which can be experienced after a single episode of alcohol consumption, starting when blood alcohol concentration (BAC) approaches zero”, and recommend to use this new definition in future hangover research.

The aim of this study was to critically evaluate and compare the different methods to assess overall hangover severity. Currently, there are three multi-item hangover scales that are commonly used for this purpose. All of them comprise a number of hangover symptoms for which an average score is calculated. These scales were compared to a single, 1-item scale assessing overall hangover severity. The results showed that the hangover symptom scales significantly underestimate (subjective) hangover severity, as assessed with a 1-item overall hangover severity scale. A possible reason for this could be that overall hangover severity varies, depending on the frequency of occurrence of individual symptoms included in the respective scale. In contrast, it can be assumed that, when completing a 1-item overall hangover scale, the rating includes all possible hangover symptoms and their impact on cognitive and physical functioning and mood, thus better reflecting the actually experienced hangover severity. On the other hand, solely relying on hangover symptom scales may yield false positives in subjects who report not having a hangover. When the average symptom score is greater than zero, this may lead to non-hungover subjects being categorized as having a hangover, as many of the somatic and psychological hangover symptoms may also be experienced without consuming alcohol (e.g., having a headache). Taken together, the current analyses suggest that a 1-item overall hangover score is superior to hangover symptom scales in accurately assessing overall hangover severity. We therefore recommend using a 1-item overall hangover rating as primary endpoint in future hangover studies that aim to assess overall hangover severity.

The purpose of this systematic review and meta‐analysis was to critically review the (1) prevalence of alcohol mixed with energy drink (AMED) consumption, (2) motives for AMED consumption, (3) correlates of AMED consumption, and (4) whether AMED consumption has an impact on (a) alcohol consumption, (b) subjective intoxication, and (c) risk‐taking behavior.Overall a minority of the population consumes AMED, typically infrequently. Motives for AMED consumption are predominantly hedonistic and social. Meta‐analyses revealed that AMED consumers drink significantly more alcohol than alcohol‐only (AO) consumers. Within‐subject comparisons restricted to AMED consumers revealed that alcohol consumption does not significantly differ between typical AMED and AO occasions. On past month heaviest drinking occasions, AMED users consume significantly less alcohol on AMED occasions when compared to AO occasions. AMED consumers experience significantly fewer negative consequences and risk‐taking behavior on AMED occasions compared with AO occasions. Meta‐analyses of subjective intoxication studies suggest that AMED consumption does not differentially affect subjective intoxication when compared to AO consumption. In conclusion, when compared to AO consumption, mixing alcohol with energy drink does not affect subjective intoxication and seems unlikely to increase total alcohol consumption, associated risk‐taking behavior, nor other negative alcohol‐related consequences. Further research may be necessary to fully reveal the effects of AMED.