When a person drinks, they digest alcohol into their bloodstream. The alcohol and blood is pumped to the brain where it leaks into different parts, including the cerebral cortex, cerebellum, and the limbic system. In the brain, alcohol latches onto the membrane of cells. It affects the neurotransmitters sent between different cells. These messages control what a person thinks, does and feels. By inhibiting some messages, and encouraging others, alcohol changes behaviors and thoughts.
The largest part of the brain, the cerebral cortex, controls higher brain functions. When alcohol gets into the neurotransmitters in the cerebral cortex, it can affect thought processes. This leads to potentially poor judgment, and depressed inhibitions.
This often causes the drinker to become more confident and talkative. In addition, it can blunt the senses and increases the drinker’s threshold for pain. Alcohol also affects function in the cerebellum, which controls fine muscle movements and balance that makes the drinker commit what we commonly call party fouls.
The limbic system controls automatic processes of the brain like hunger, sexual arousal, emotion, and memory. Alcohol affects the brain’s function of all of these processes. As a person increases their consumption of alcohol over an evening it can cause short-term memory loss, or even blackouts. Another example is the increase in sexual arousal and simultaneous decrease in sexual performance. Alcohol is also a diuretic; it stops the release of a hormone that prevents constant urination. This explains why there is always such a long bathroom line at the bar.
There are many causes for the different symptoms of a hangover. For example, because alcohol is a sedative, the brain counteracts the effect by releasing stimulants that cause nausea, and light and sound sensitivity. As blood alcohol levels decrease, these stimulants are left in your body without anything to balance them out.
The infamous hangover headache is caused primarily by dehydration. The body’s organs compensate this loss for water, by stealing water from the brain, causing it to decrease in size. This change in pressure causes headaches.
Alcohol affects the brain also because it disrupts sleep patterns, by slowing down a neurotransmitter in the cortex. Although a drinker will feel very tired, the alcohol will initially suppress REM or dreaming while asleep. When the effects of the alcohol wear away, the body compensates by producing an REM backlash. This means that in the later hours of sleep, the drinker has more dreams but gets less rest. As a result, besides the headache, many wake up the next morning feeling irritable.
Alcoholics over a lifetime often suffer from severe permanent changes to the brain especially the cerebellum. Diseases such as the Wernicke-Korsakoff syndrome or hepatic encephalopathy are caused when alcohol reduces the body’s ability to absorb essential nutrients. These cause mental confusion, paralysis of nerves that move the eyes, and an impaired ability to coordinate movements. Often, patients go on to form lasting psychosis, behavioral abnormalities and memory impairments.
Alcohol affects the brain and damages the ability of the brain to create new brain cells and destroys existing ones. It has been found that people that consumed alcohol had smaller brain sizes, as they grew older.
It is important to remember that drinking does not affect every person the same way. Age, drinking history and genetics are some of the factors that influence how a body reacts to alcohol. Watch the video below on an overview of alcohol and your brain.