Alcohol impairs brain function – long-term use may cause skewed thinking
What actually happens when alcohol goes to your head? "Alcohol has an impairing effect on the brain. It starts in the cortical brain regions, which control our behaviour and display of emotions. The effects are exactly what drinkers often expect to get from alcohol: lack of restraint and decreased social inhibition," says Senior Researcher Olli Kärkkäinen.
"When we drink more, we often lose too much of control and other areas of our brain also become affected. The effects include staggering, slurred speech and memory blackouts, and heavy drinking may finally lead to unconsciousness and respiratory failure."
People who are used to drinking alcohol may seem sober even after they have had several drinks, because long-term alcohol use changed the way our brain functions. "Fighting the effects of alcohol, the brain tries to maintain normal activity. This is why heavy drinkers need to drink more in order to induce the same effect that lower doses have on other people. The delirium during alcohol withdrawal is partly caused by a change in the brain when the impairment from alcohol is replaced by a hyperactive state."
Long-term heavy drinking appears to alter the structure of the brain and the functioning of neurotransmitters. "Some changes that are considered to reinforce addiction occur in the dopamine system, which controls motivation, among other things, and in the serotonin system involved in regulating emotions. Decision-making becomes skewed, so that the motivational role of alcohol increases while other factors that are usually considered rewards, such as food, sex and social life, lose their appeal," says Kärkkäinen.
Decreased brain volumes have recently been observed in middle-aged moderate drinkers as well. In a study conducted in Kuopio, heavy but socially acceptable drinking among young adults has been linked to loss of grey matter in the brain, and in men, to loss of white matter connecting brain areas. "It is unclear, however, whether there are other background and individual factors involved, and how the structural changes are linked to the risk of dementia later in life, for example."
The CAIDE (Cardiovascular Risk Factors, Aging, and Incidence of Dementia) Dementia Risk Score tool showed an increased risk of dementia for drinkers with the APOE4 genotype. Approximately one-third of Finns have this genotype.
Even if alcohol is not a problem at a younger age, it can slowly take control over the years. "Alcohol use at a young age, when the areas of the brain related to self-regulation have not yet fully developed, appears to increase the risk of alcohol addiction later in life. Childhood traumas are also a contributing factor to addiction, and when alcoholism runs in the family, one might be better off not using alcohol at all."
Kärkkäinen has studied the consequences of heavy drinking, for example, by examining post mortem brains of persons with alcohol dependence. In recent years, he has been using metabolomic profiling to study the effects of alcohol on small molecules in blood samples. "The goal is to find markers that will enable us to identify the risk of alcohol addiction or organ failure early on. New markers could also help select the most suitable way to treat alcohol addiction."