Adverse Effects of Alcohol on the Brain

The knowledge of how alcohol affects the brain comes mostly from research done on older individuals, usually former and\or current alcoholics. How alcohol affects the central nervous system of adolescents is poorly understood for several reasons: alcohol is an illegal drug when consumed by adolescents, there is a lack of adolescent volunteers willing to undergo experiments because alcohol is illegal for their age group which may lead them to incrimination or other troubles with authority figures (including parents), and any research done on adolescents using alcohol would have to be approved by the Human Subjects Committee. What is known on alcohol’s effects on the brain comes from work done with older alcoholic adults, and research on adolescents has only been attempted in a few European countries to date.

The following is just a taste of what alcohol does to various parts of the brain. The effects are by no means limited to just the following:

Cerebellum: The cerebellum is a structure on the bottom base of the brain. Its role is to regulate the motor activity of the body, and it does this by receiving information from the cerebrum (located all around the top of the brain from which intelligent thought processes are born) about what kind of coordinated movement is desired. With this knowledge, the cerebellum will “write” the program on how to do this movement. Because the cerebellum controls the motor activity of the body, it’s one of the parts of the brain, which is more easily accessible for various studies (including, the sobriety test). The cerebellum is also thought to be affected the most by alcohol since it's significantly smaller in alcoholics compared to individuals with no alcoholic problems. Although this is under scrutiny a reduced cerebellum is more visible under observation than the other parts of the brain which might be equally impacted.

Hippocampus: Buried deep within the brain lies the hippocampus within which new memories are consolidated from short-term ionic memory to long term memory. The hippocampus also plays a prominent role in how we learn. Its location makes it difficult for studies to be done on it without the benefit of Magnetic Resonance Imaging (MRI) or other forms of scanning techniques. Researchers investigating this part of the brain found that adolescents who do drink alcohol, and who do drink significant amounts tend to have hippocampi that have shrunk ten percent compared to normal healthy hippocampi. This shrinkage in brain volume signals the death of brain cells. Ten percent of brain cells lost this way due to alcohol is a lot of brain cells. Perhaps the most used drug among teens is also the most dangerous. Further studies have shown that learning is impaired as a result of the hippocampus shrinking. Tests done to evaluate skills and knowledge in math, the sciences, and verbal/nonverbal abilities show a ten percent decline in people who drink heavily and who exhibit a decline in the size of the hippocampus.

Other parts of the brain: The extent to which alcohol affects other parts of the brain is still unknown. One reason is that signs that some areas are affected are more obvious, more visible, and more easily recorded. Signs like shaking of the limbs and other movements of the body indicate more damage to certain areas of the brain. If the cerebellum is affected more than the other parts of the brain (and autopsies of alcoholics help support this assumption) help support this assumption) then the reason why the cerebellum is more acceptable to damage by alcohol is still unknown.

· All drug addictions can be traced back to the limbic system as it’s the reward center for various activities such as eating, quenching a thirst and having sex. While the mechanism is still very unclear as to how alcohol creates a buzz, this part of the brain has long been suspected.

· Dopamine, one of the neurotransmitters in the reward system, has also been suspected in alcoholic addiction.

Killing brain cells by drinking?

The exact reason why alcohol kills brain cells is also still under debate, especially when there’s evidence in vitro (in vitro meaning evidence coming from outside the body) supporting one theory over the other. Using a growth medium in a petri dish, investigators can grow neurons and observe neurons dying from alcohol; however, researchers must ask the question “Does this really happen in vivo (inside the body)?” as we are unable to fully visualize nor recreate the complex metabolic actions brain cells would experience within the brain.

One theory suggests that alcohol causes osmosis reactions (the pulling out of water) within the cell, because the water flows to areas of lesser concentrations of water. Once the cell loses enough water, the cell membrane structure is lost, and without the cell membrane structure, membrane functions are affected, and without membrane functions, the neuron can’t fire if the membrane loses its charge potential. If the neuron can’t fire, it’ll die.

Another theory as to why alcohol kills brain cells comes from what the cell membrane is composed of: lipids. Because alcohol dissolves like molecules, and since alcohol has an attraction towards lipids, perhaps alcohol attacks the very structure that makes up most of the cell membrane. However, some would argue that alcohol doesn’t have as much a direct attack against cells as the previous theory suggests.