Frequent alcohol consumption can reduce intelligence

Millions of Germans drink a dangerous amount of alcohol. Michael Soyka, who has been researching the consequences of addiction for 25 years, explains how long-term consumption affects the psyche. The specialist in psychiatry and psychotherapy teaches at the university hospitals in Munich (LMU) and Bern and runs a private psychiatric clinic in Meiringen, Switzerland.

Süddeutsche.de: Prof. Soyka, what does alcohol do to people?

Michael Soyka: Alcohol is a cell poison. In the long term, it leaves traces all over the body, including the brain. The frontal lobe, which determines personality and critical faculties, is particularly sensitive to alcohol.

Süddeutsche.de: How is brain damage from alcohol manifested?

Soyka: The ability to react decreases, the ability to criticize diminishes, the emotional life gets out of control - you laugh at things that you might not have laughed about before. The intellectual level drops. With pronounced brain damage, concentration, short-term memory and retentiveness suffer. This can go as far as dementia. Psychoses, delusions or hallucinations are less common. An extreme form is the Wernicke-Korsakoff syndrome with complete memory loss.

Süddeutsche.de: What is going on in the brain? Do the nerve cells die?

Soyka: Yes, you can also measure that with imaging methods. The alcohol has a toxic effect on the neurons. In addition, there are liver metabolic disorders and various other factors that affect the nerve cells.

Süddeutsche.de: Do you have to be a heavy drinker or do your brain cells die from a beer after work?

Soyka: It is usually a gradual process. It is assumed that the risk of physical damage increases exponentially with the amount of drink. This means that nothing happens for a long time at low doses, but then the risk increases massively. Ultimately, it is not possible to say with certainty when the critical threshold has been exceeded. We researchers can only make statements about a statistical risk. I think anyone who has been drinking a lot for five to ten years usually has some brain damage. Of course there is always a patient who drinks a bottle of vodka a day and has no brain damage. But that's the big exception.