The hangover – that discomfort of the “day after a party” – is often trivialized, mocked, or even made a rite of passage. But it is also now a medically recognized phenomenon, since codified by the World Health Organization (WHO) in the latest version of the International Classification of Diseases (ICD-11).
What does scientific research tell us about the causes of this unpleasant state and its consequences? Are there any predispositions? Remedies that work? What changes does the fact that hangovers are now recognized as a medical entity in its own right change? Here are the answers.
What is a hangover?
Hangover “alcohol hangover”) refers to the set of symptoms that appear when the alcohol level in the blood has dropped to zero, generally several hours after excessive consumption. This state lasts from six to twenty-four hours.
According to the Hangover Research Group, an international collective of researchers specializing in the scientific study of hangovers and recent scientific literature, the symptoms are of three types:
- Physical: headache, nausea, vomiting, fatigue, dry mouth, tremors, tachycardia, sleep disturbances;
- Psychological and cognitive: anxiety (illustrated by the English portmanteau “hangxiety”), irritability, depressed mood, attention and memory problems, cognitive slowness;
- Physiological: systemic inflammation, oxidative stress, electrolyte imbalance (electrolytes present in the blood, such as sodium or potassium for example, are involved in several biological processes, notably nervous and muscular functions), hypoglycemia (decrease in blood sugar levels), disruption of the circadian rhythm (the “internal clock” which regulates our body), disruption of neurotransmitters (the chemical messengers which allow neurons to communicate with each other) such as glutamate and dopamine.
Can we predict who will have a hangover?
If a hangover can occur from moderate alcohol consumption (of the order, for example, of four drinks in one evening), the minimum dose varies greatly depending on the individual. Various moderating factors have been well identified. This is particularly the case for the speed of ingestion: the more quickly the alcohol is consumed, the higher the blood alcohol peak, which increases the risk of a hangover.
Biology also plays a role, whether it is gender (we know, for example, that women eliminate alcohol more slowly than men), weight, state of health, or even genetics, which influences enzymatic processes (in particular those involving the enzymes involved in the detoxification of alcohol, such as alcohol dehydrogenase and aldehyde dehydrogenases).
Age also plays a role: Young adults are more prone to hangovers than older people. Young adults tend to consume more quickly and in larger quantities on festive occasions (binge drinking), which greatly increases the risk of a hangover.
Older people often consume more moderately and regularly. With age, some people naturally reduce their consumption and learn to avoid excesses and anticipate the effects. They respond less to the inflammatory effects of alcohol and report fewer hangover symptoms.
Finally, physical state (hydration level, sleep, prior diet) also influences symptoms. Drinking on an empty stomach, without ingesting water or getting enough sleep, increases the symptoms.
Hangover and “blackout”: a worrying link
Alcoholic blackouts, or peri-event amnesia, reflect an acute disruption of the hippocampus, a brain structure that plays an essential role in memory. By interacting with certain receptors present in neurons, alcohol blocks the molecular mechanisms that allow memorization; the brain then no longer prints the memories…
Although these blackouts are not synonymous with hangovers, they are often associated with them. Indeed, such loss of memory indicates severe intoxication, therefore a higher risk of hangover… and long-term brain damage!
A risk factor for addiction?
Several studies suggest a paradox in the link between hangovers and addiction. So, although a hangover is an unpleasant experience, it would not necessarily deter future alcohol consumption and may even be associated with an increased risk of alcohol addiction. For example, one study suggested that frequent hangovers among young people constitute a specific and independent predictive marker of the risk of developing alcohol addiction later in life. This link appears to reflect a particular vulnerability to the aversive effects of alcohol.
Among “social” drinkers, who are characterized by festive alcohol consumption, without presenting an addiction to alcohol, a severe hangover is often a deterrent. However, in certain risk profiles (young, impulsive individuals, or with a family history), a hangover does not lead to a reduction in consumption. Worse: it is perceived as a tolerable inconvenience which reinforces the drinking habit and this response to the subjective effects of the hangover thus constitutes a factor of vulnerability to alcohol addiction, particularly if the individual seeks to relieve the hangover… by drinking again (vicious circle).
No miracle cure
Sparkling water, broth, vitamin C, aspirin, grilled bacon, sauna, pickle juice, “hair of the dog” (“hair of the dog”, which actually means another drink)… Popular literature is rich in grandmother’s remedies supposed to relieve hangovers.
According to everyone, to avoid or limit the inconveniences linked to excessive alcohol consumption, it is necessary to rehydrate (water, broths), support the liver (milk thistle, cysteine), reduce inflammation (antioxidants, ibuprofen), boost dopamine (coffee, chocolate) or even restore electrolytes (sports drinks)… However, to date, the effectiveness of these different remedies has not been supported by any solid scientific evidence.
In 2020, a systematic review of the scientific literature concluded that there was no demonstrated effectiveness of the interventions analyzed, with the effectiveness results deemed “very low quality”. This work included twenty-one randomized controlled trials, analyzed twenty-three different treatments, and concluded that the overall quality of evidence is very low, according to the GRADE system (Grading of Recommendations Assessment, Development and Evaluation).
Previously, other works had also reached the same conclusion. The best prevention therefore remains to drink moderately, slowly and to hydrate.
An ethical issue: should hangovers be treated?
The fact that hangover is now recognized as a medical entity raises questions. This semantic shift is risky: it could trivialize excessive alcohol consumption and even encourage consumption. Is there a risk that one day we will see doctors prescribing a preventive “treatment” to allow us to drink more without suffering?
The medicalization of hangovers could also have a perverse effect: considering that it is possible to “drink without consequences”, provided that you take good care of yourself afterwards… We must not forget that a hangover is not a simple inconvenience: this state is the reflection of intense stress inflicted on the brain and the rest of the body. Understanding it means better protecting yourself and, perhaps, also thinking about your consumption habits.
On this subject, if you wish, you can self-assess your hangover symptoms using this French translation of the Hangover Symptom Scale (HSS).
