Is hangover the same as alcohol withdrawal?

Although a significant amount of overlap exists in the symptoms of hangover and alcohol withdrawal, the two conditions are not the same. Hangover symptoms occur after a single bout of heavy drinking; alcohol withdrawal occurs when someone who regularly drinks alcohol suddenly stops drinking or begins to drink less. Regular alcohol consumption results in neurochemical changes: increased excitatory N-methyl-D-aspartate (NMDA) neuroreceptors and decreased responsiveness of the inhibitory gamma-aminobutyric acid (GABA) receptors in the brain. Without the regular dose of alcohol, NMDA receptors are excessively excited by glutamate and GABA receptors cannot adequately inhibit this excitation. This presents as symptoms of alcohol withdrawal — which include anxiety, confusion, exhaustion, headaches, irritability, shaking and tremors, and sleeplessness — and in the worst case, as hallucinations and seizures that can become severe enough to lead to death.^[1]

There are other major differences between alcohol withdrawal and hangover. Hangover symptoms typically begin within hours of drinking cessation (when BAC reaches zero) and can resolve within 24 hours. In contrast, symptoms of alcohol withdrawal can begin several hours to days after someone stops drinking, and symptoms can last for a week or longer, though they’re typically at their worst around days 2–3.^[1]

In summary, while anyone can experience an alcohol hangover, only individuals who have developed a tolerance for alcohol can experience alcohol withdrawal and the associated symptoms.