How Alcohol Affects the Brain: Part II


Written by Katie Esposito

A lot of people think they know the effects that long-term alcohol dependence has on the brain. Many of their ideas are wrong. Alcohol consumption, in most cases, does not cause permanent defects in reasoning, memory, or other forms of cognition. After a couple years of sobriety, this functioning returns to normal. However, there are two main exceptions, when long-term damage can be severe and life altering. The first is Wernicke’s Korsakoff Syndrome.

Wernicke’s Korsakoff Syndrome

More commonly known as “wet brain,” this syndrome is actually caused by thiamine (vitamin B1) deficiency. It happens to people who are long-term alcohol dependent because alcohol blocks the absorption of thiamine. This syndrome arrives in two stages. The first is Wernicke’s encephalopathy, which causes a number of serious neurological problems, such as muscle spasms, paralysis of the eye muscles, and general confusion. During this stage, the disorder can be reversed with thiamine supplementation. But, if no one intervenes, it progresses quickly into Korsakaff psychosis, which is incurable.

At this stage, the individual experiences permanent memory loss and confabulation (creation of new but untrue memories), learning problems, hallucinations, unsteadiness on his or her feet and dementia. It’s ideal to catch the disorder before it gets this far, but, sadly, this is not often the reality.

To prevent either stage from happening, problem drinkers need to watch their vitamin B intake.

Hepatic Encephalopathy

This one has nothing to do with vitamin intake. Instead, it has to do with the liver. When the liver can no longer filter toxins out of the blood, these toxins – like manganese and ammonia – circulate through the body and damage brain tissue. The damage to the brain can slow down reaction time and create general apathy. Sometimes people with hepatic encephalopathy appear drunk even when sober, due to slurred speech and behaviors that lie out of social norms, or even norms for them before the damage occurred. In advanced stages, the brain shuts down completely, leaving the person in a coma. Note that liver failure has to occur first before this disorder becomes symptomatic.

So, otherwise, there’s no brain damage, right?

Well, no. It’s just that most of it’s repairable over time. While heavy drinking constricts blood vessels and can shrink the brain, one type of brain cells appear to be permanently damaged once the person achieves sobriety: the gray cells in the parietal lobe, the part of the brain in charge of spatial processing. Even years after he or she stops drinking, a dependent drinker can have trouble figuring out how things relate to each other, such as judging distances on a map or putting a puzzle together.