Alcohol interferes with the brain’s communication pathways and can affect the way the brain looks and works. Alcohol makes it harder for the brain areas controlling balance, memory, speech, and judgment to do their jobs, resulting in a higher likelihood of injuries and other negative outcomes. Long-term, heavy drinking causes alterations in the neurons, such as reductions in their size. 


The developing brain is particularly vulnerable to effects of alcohol. Misuse of alcohol during adolescence and early adulthood can alter the trajectory of brain development, resulting in long-lasting changes in brain structure and function.


One significant consequence of alcohol misuse is alcohol-induced blackouts. Blackouts are gaps in a person’s memory for events that occurred while they were intoxicated. These gaps happen when a person drinks enough alcohol to temporarily block the transfer of memories from short-term to long-term storage—known as memory consolidation—in a brain area called the hippocampus. 


Continuing to drink despite clear signs of significant impairments can result in an alcohol overdose. An alcohol overdose occurs when there is so much alcohol in the bloodstream that areas of the brain controlling basic life-support functions—such as breathing, heart rate, and temperature control—begin to shut down. Symptoms of alcohol overdose include mental confusion, difficulty remaining conscious, vomiting, seizure, trouble breathing, slow heart rate, clammy skin, dulled responses such as no gag reflex (which prevents choking), and extremely low body temperature. Alcohol overdose can lead to permanent brain damage or death.