Alcohol on the Brain (citations)


Many of the behaviors we see when a person is under the influence of alcohol are directly tied to the effect alcohol has on the brain. Alcohol is classified as a depressant, which means that alcohol slows brain activity. In the most severe cases alcohol slows brain activity so much that the drinker’s brain stops sending signals to the heart to pump blood. More commonly, alcohol influences the parts of the brain responsible for judgment, coordination, and memory:

Interestingly, the behaviors often associated with alcohol consumption (sociability, rowdiness, and poor judgment) are also the result of alcohol’s slowing of brain activity. This is because alcohol slows the brain activity in the part of the brain that tends to keep in check, or in inhibit, self-judgment. As a result, individuals are left at a disadvantage when it comes to fully thinking through their actions. This makes the individual less nervous to engage another in conversation but also less likely to realize the consequences of engaging in risky behaviors, such as drunken driving.1

The part of the brain that is associated with coordination becomes less active under the influence of alcohol. Consequently, the brain’s ability to manage movements deteriorates as the individual becomes more intoxicated. A brain with alcohol in the system has poorer balance, hand-eye coordination, and reaction time than when compared to brains without alcohol. Alcohol also has the effect of making someone drowsy or sleepy.2

Blackouts are another important effect of alcohol on the brain. Like alcohol’s effect on other parts of the brain, it slows the activity in an area called the hippocampus that is associated with forming new memories and recalling memories. When alcohol is consumed in excessive amounts it can keep the brain from forming new memories. When the individual cannot remember what happened during an episode of drinking it is called a blackout. In cases where the individual remembers what happened only after reminders from friends, the event is called a brownout. Both are signs of alcohol’s impairment of the brain’s memory structures.3


1 White, A.M., Ghia, A.J., Levin, E.D. & Swartzwelder, H.S. (2000) Binge pattern ethanol exposure in adolescent and adult rats: Differential impact on subsequent responsiveness to ethanol. Alcoholism: Clinical and Experimental Research, 24(8), 1251-1256.

2 White, A.M., Truesdale, M.C., Bae, J.G., Ahmad, S., Wilson, W.A., Best, P.J. & Swartzwelder, H.S. (2002). Differential effects of ethanol on motor coordination in adolescent and adult rats. Pharmacology, Biochemistry and Behavior, 73,673-677.

3 White, A.M. & Swartzwelder, H.S. (2004). Hippocampal function during adolescence: A unique target of ethanol effects. New Annals of the New York Academy of Sciences, 1021, 206-220.