How Alcohol Affects the Brain
It is unlikely that when a person is in the midst of a drinking binge or having a quiet night out with a few drinks that they sit and contemplate the effects that alcohol might have on their body – let alone their brain.
The truth is that the damage alcohol can do to the brain goes far beyond a headache or that foggy feeling the morning after the night before. The effects of drinking alcohol on the brain are profound – indeed, heavy drinking can set you on a path to acquiring some of the worst brain diseases. That's because the long-term effects of alcohol have a tendency to completely re-wire the brain – increasing the risk of depression and other conditions.
The impact that alcohol has on the brain is very complex. Most people are aware that long-term alcohol abuse will have detrimental consequences for the body – leading to conditions such as cirrhosis of the liver. What's surprising though is that a new survey carried out this year (2018) in France shows a strong link between excessive alcohol intake and early onset dementia – individuals begin to show these symptoms before the age of 65.
The study indicates that heavy alcohol use, as well as other alcohol use disorders, is an important risk factor for dementia, which can shorten lives by up to 20 years - with dementia as the leading cause of death.
Up until now, dementia has usually been associated with Alzheimers disease, but the study proves there is a definitive link between it and alcohol misuse. To understand the link between the two, it is first useful to understand the effects that alcohol has on the brain as a whole.
Three drinks a day for women and four to five drinks per day for men is what health experts constitute as heavy drinking. There are several factors that decide how alcohol impacts cognitive function. Firstly, and perhaps most importantly, it depends on how much and how frequently a person drinks. Other factors such as the age when alcohol first began being consumed in earnest, combine with prenatal alcohol exposure, age, gender and genetic background as well as the general health of the person are all deciding factors – as is the level of education a person has attained. Poor coordination, slurred speech and slower reaction times are some of the most common symptoms associated with alcoholism. Psychologically, abusers will likely experience cognitive impairment such as memory loss and impaired thinking. This can drastically affect relationships with loved ones and co-workers. Aside from this, people who consume too much alcohol are usually more inclined to engage in risky behaviour, with an addictive personality and will, as a result, end up with symptoms of depression.
Effects of Alcohol
When alcohol is withdrawn, a person is usually expected to experience at least one – if not all of the following symptoms: nausea, shaking, sweating, anxiety and delirium tremens (a psychotic condition typical of chronic alcoholics) – which may include hallucinations. However, there are steps that can be taken to prevent alcohol withdrawal.
When someone consumes alcohol, their liver breaks it down into non-toxic by-products but with excessive consumption, the liver is unable to keep up with the demands required, and the alcohol remains in the bloodstream. The effects of alcohol on the brain depend upon an individual's blood alcohol concentration.
An increase in blood alcohol concentration interacts with the brain through something referred to the blood-brain barrier. Once in the central nervous system, alcohol causes alterations in behavior by acting upon specific regions in the brain that are susceptible to chemical changes.
Alcohol stimulates the mesolimbic pathway – also known as the brain's reward center. It sits within the brain and releases the pleasure hormone that is dopamine.
This pathway is the major one that is involved with alcohol addiction. That's because a constant stimulation of this pathway means that, over time, an increased amount of substance is needed – in this case alcohol – to create the same levels of pleasure. Research has shown that a pathway that is repeatedly stimulated by alcohol becomes covered in a mesh-like glue that makes it difficult to form new synapses or break old ones. This explains why addiction is so tough to overcome because the pattern becomes ingrained and is held together in that way in the brain.
The frontal lobe and prefrontal cortex are the regions in the brain that are responsible for decision-making, motivation, judgment and problem solving among others. It also controls a person's social conduct and inhibitions. Studies into neuropathology have shown a large reduction in the number of neurons in the prefrontal cortex of alcoholics and overall reduced brain mass relative to controls, which, in this case, were people who didn't drink. Therefore, alcoholics who have damaged their frontal lobe and/or their prefrontal cortex may find that they experience personality and emotional changes.
The hippocampus lies within the mesolimbic system and is involved in motivation, spatial navigation, and emotion. It is also crucial for the formation of memories. Evidence also indicates that the hippocampus might also play a role in fear and anxiety and is also one of the few sites for neurogenesis in the adult brain. Neurogenesis is the process of new brain cells being formed from stem cells.
The Hypothalamus is also part of the limbic system. However, it has many connections to a variety of different systems – including being involved in learning and memory function, eating and drinking, controlling body temperature and regulating hormones and emotions. If the hypothalamus is damaged due to alcohol abuse, then a person is likely to experience memory loss and, in severe cases, experience amnesia.
The cerebellum makes up around ten percent of the brain's weight and holds around half of the brain's neurons. Despite its small size, the cerebellum is in charge of coordinating voluntary movement, balance, and eye movement. It also helps to control cognition and emotion – if the cerebellum is exposed to alcohol abuse, it leads to atrophy within the white matter housed there.
The amygdala sits within the temporal lobe and is also connected to the prefrontal cortex, the hippocampus and the thalamus and controls emotions like love and fear and helps a person identify danger – the body's in-built fight or flight system. When the brain is exposed to long-term alcohol abuse, its chemistry is altered as a result of neurotransmitters being affected in the various areas in the brain.
Neurotransmitters are the messengers of the brain that send signals within the central nervous system and throughout our body. If neurotransmitters are altered as a result of alcohol abuse, then the various brain elements will see changes that will impact on the person's behavior and motor functions. Neurotransmitters either increase electrical activity in the brain – if they are excitatory. But, if they are inhibitory, then they will decrease the brain's electrical activity.
Hooked On A Feeling
The consumption of alcohol tends to slow the brain's function down because it binds to the GABA and NMDA receptors – the result is that speech becomes slurred and memory fails and fatigue sets in.
Initially, alcohol will cause the release of norepinephrine as well as adrenaline and an increase in the body's cortisol levels and the happy hormone – dopamine. The person drinking will experience a high, and feel stress-free and the life and soul of the party. However, if alcohol abuse becomes chronic and these neurons become impaired, then norepinephrine release becomes less and as a result the person will not be able to focus for any period of time, will fail to process information effectively and as a result will be unable to retain information and will suffer memory loss.
Alcohol Is A Drug
Research suggests that alcohol's effect on dopamine is more significant for men than women, which may account for men drinking more than women on average. According to results from the 2001-2002 National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), alcoholism affects men more than women: About ten percent of men, compared to three to five percent of women, become alcoholics over the course of their lifetime.
Over time, with more drinking, the dopamine effect diminishes until it's almost non-existent. But at this stage, a drinker is often "hooked" on the feeling of dopamine release in the reward center, even though they're no longer getting it. Once a compulsive need to go back again and again for that release is established, addiction takes hold. The length of time it takes for this to happen depends on the individual - some people have a genetic propensity for alcoholism and for them it will take very little time, while for others it may take several weeks or months.
An example of an excitatory neurotransmitter is glutamate, which would normally increase brain activity and energy levels. Alcohol suppresses the release of glutamate, resulting in a slowdown along your brain's highways. In other words, if alcohol is part of the equation, then the glutamate is prevented from binding to its NMDA receptor. As a result of this inability to bind, the person will experience symptoms of depression. A similar neurotransmitter is serotonin, which is responsible for the pleasure and reward effects that are controlled by the mesolimbic pathway. According to research, chronic alcohol abuse leads to a fifty percent reduction in serotonergic cells, which leads to sleep disruption, low mood, and a decreased appetite.
Following the initial increase of the excitatory neurotransmitters with the first couple of drinks consumed, the stimulation wears off, and there is a build-up of the inhibitory neurotransmitters - GABA and NMDA. This results in the binge drinker feeling depressed, miserable and exhausted after a night of over consumption.
Studies have revealed that there is an overall decrease in neuronal density, blood flow to various regions in the brain and the body's ability to metabolize glucose.
The body needs the vitamin B1 – also known as Thiamine - to metabolize glucose. However, after a period of excessive drinking, this vital nutrient also decreases. It is essential for all the body's tissues, with the brain being paramount. The brain needs thiamine because of its critical role in glucose metabolism and neurotransmitters synthesis.
The body's thiamine levels decrease due to alcohol consumption – mainly due to a lack of a balanced diet, but also the alcohol prevents the body from properly absorbing it and then activating it. The body does have reserves of thiamine, but they are likely to become depleted during heavy drinking. If heavy drinking becomes chronic, then those reserves don't have to ability to rebuild themselves and an individual will start to show signs of thiamine deficiency. Of the people with a thiamine deficiency due to alcohol consumption, eighty percent will usually go on to develop Wernicke Encephalopathy – which is a form of mental confusion and will also experience eye problems as the muscles that control eye movement become affected. They might also experience overall loss of muscle coordination.
Furthermore, up to ninety percent of people suffering from Wernicke encephalopathy (neurological disorder) will also develop Korsakoffs psychosis (chronic memory disorder). Symptoms include difficulty walking and severe memory loss. They will also be unable to make new memories.
But perhaps the most worrying of all drink-related diseases that affect the brain is dementia. Research shows the risk of developing it is three times greater in heavy drinkers than other people. Dementia due to alcohol encompasses both Wernicke encephalopathy and Korsakoffs psychosis.
Other impacts felt by the brain after prolonged alcohol abuse include Cerebellar Syndrome with Anterior Superior Vermal Atrophy. This is where a patient presents symptoms of a broad-based gait, difficulty with eye movements and slowed or slurred speech. Added to this, excessive alcohol consumption over a period of time sees a variety of molecular and chemical changes in the brain that results in a change in the person's behavior and can have an impact on their physical wellbeing too. Global cell death is common – especially in very vulnerable areas in the brain – which will see the brain shrink in size. However, if a person refrains from drinking over an extended period, there is a chance that some cell regeneration might take place in areas such as the cortex and hippocampus.
It's worth noting that even moderate alcohol consumption can have a detrimental impact on brain function. In the past, it was thought that the odd glass of red wine could protect it, but a new study carried out in 2016 pushes back on this notion, and while the research linking excessive alcohol to dementia is still in its infancy, it should act as a stark reminder that over consumption of alcohol will have a negative impact on all the body's major organs – not least the brain. When wondering if you or a loved one may suffer from alcohol addiction, it's best to stick to the national guidelines when it comes to alcohol consumption. Seek help at Peaks Recovery if you think the amount you're drinking is becoming a problem.