Alcohol and nervous system

Most of us who enjoy drinking alcohol know that after a hideously stressful day at the office it’s the norm to go out with friends for a “pick-me-up” drink, or go home and collapse on the couch to relax with a beer or glass of your favourite wine.

But before you take that next swig, have you ever thought what alcohol does to your body,and more specifically, to your nervous system?
Not to be a killjoy, but like with most things, moderation is the key word when consuming alcohol.

Is your colleague an alcoholic?

Turns out that South Africans like to drink; in fact, we are some of the biggest boozers in the world, according to the World Health Organisation (WHO).

Consider this sobering statistic:

About 130 people in South Africa die each day due to alcohol related incidents, says Professor Charles Parry, director of the Alcohol and Drug Abuse Research Unit at the South African Medical Research Council (MRC).

His concern goes beyond statistics; he says various non-communicable diseases (NCDs) and conditions are "entirely attributable to alcohol". These include many mental and behavioural disorders, foetal alcohol syndrome (FAS) and nervous system damage.

Foetal alcohol syndrome highest in SA 

“The more alcohol you drink, the more problematic these disease-related complications become,” Professor Parry warns.

How exactly does alcohol affect your central nervous system (CNS), (i.e. your brain and spinal cord) and peripheral nervous system (PNS)?

The CNS plays such vital roles that your body cannot survive without it. These include taking in and processing information through the senses, controlling complex motor functions as well as other tasks like reasoning, thinking and, understanding.

Alcohol acts as a depressant on the brain and other nerve tissue. This means it slows down the functioning of nerves cell and activity in the CNS, explains neurologist Dr Stuart Kieran of Bitterroot Neurology in Montana, USA.

It might sound odd, since most people usually become less reserved and more animated after drinking alcohol. Fact is, the acute feeling of euphoria or loss of inhibition is not stimulation, says Dr Kieran, but rather the result of "certain areas of the brain that normally control judgment, reasoning and instincts being suppressed".  

How alcohol affects your brain

As you continue drinking and more alcohol enters your brain, it impairs your judgement, vision and alertness; dulls the senses; affects concentration; slows your reaction time; and decreases coordination. Just observe a few people having a drink or three and it will soon become obvious that everyone responds differently to alcohol and has varying tolerance levels.

Take this test to see if you are drinking too much

Many factors influence "how and to what extent alcohol affects your brain", according to the National Institute on Alcohol Abuse and Alcoholism. These include how much and how often you drink; at what age you started drinking; your gender; weight; general health status; and family history of alcoholism.

In addition, whether you’re consuming alcohol with food, the period over which you drink, whether you’re mixing it with other drugs like marijuana and even your mood and psychological make-up all contribute to the way alcohol affects the CNS, says an article on Science NetLinks, an educational project linked to the American Association for the Advancement of Science (AAAS).

Long-term effects

Normally your brain’s protective blood-brain barrier prevents or slows the passage of some drugs and other damaging substances from the blood into the CNS. But that doesn’t apply to alcohol, because it’s able to cross this barrier and reach nerve cells (neurons) directly within minutes. There’s also no digestion needed for alcohol, so your body metabolises it before many other nutrients.

When a large amount of alcohol quickly enters the brain, it causes a rapid rise in blood alcohol concentration (BAC), seriously disrupting the activities of several neurotransmitters in specific areas.

If alcohol merely resulted in taking dumb decisions, walking unsteadily, slurring your speech and generally acting like a clumsy clown for a couple of hours, it would probably not be such a big deal.

Why you should kick your drinking habit

Neurologist Dr Kieran says while the acute effect of alcohol on the cerebellum (the area of the brain that controls coordination, movement, balance and complex motor functions) is temporary, chronic effects are not temporary. Alcohol can have a "toxic effect on nerve tissue and cause permanent imbalance", he remarks.

Don’t dismiss the other long-term effects alcohol can have on the body’s CNS. Aside from damaging your nerve cells permanently, long- term alcohol use can also cause short-term memory loss, forgetfulness, weakness and sensation problems like numbness or tingling.

Ways in which alcohol affects your nervous system:

· Memory impairment: Alcohol can cause memory loss (amnesia), and when used long term, can result in permanent memory loss and confusion.

· Impaired walking, reaction time and hand-eye coordination: Alcohol can affect both the inner ear and cerebellum that are involved in balance and coordination, causing walking and sensation difficulties.

· Sleep disturbances: While small amounts of alcohol may initially have a sedating effect, it disrupts sleep overall. It can also cause nightmares and aggravate sleep apnoea, a potentially serious sleep disorder where breathing constantly stops and starts.

· Behavioural changes: The ethanol in alcohol can cause damage to brain neurotransmitters. If this damage is ongoing, it can result in behavioural and mood changes such as depression, anxiety and seizures.

· Alcoholic blackouts: This occurs when you quickly drink a large amount of alcohol. You are still conscious, awake, and able to move, walk and talk, but cannot recall some or all of the events that happened while intoxicated. Individuals that have an alcohol blackout are 70% more likely to get alcohol poisoning, requiring emergency medical treatment.

· Peripheral neuropathy: Chronic or heavy alcohol use can cause this disorder, which involves damage to the peripheral nerves in the feet and legs, resulting in malfunctioning. Peripheral neuropathy produces lack of sensation in the feet, which contributes to unsteadiness.

Bottom line, says Dr Kieran, is that while using "small amounts of alcohol in a responsible way" can be enjoyable for many, remember that just like any other drug, alcohol has many potential side effects and consequences.