The branched network of the reward system is activated when we expect a reward or when we give in to a craving, such as eating when we are hungry. The main messenger is dopamine. It creates the anticipation of happiness, motivates action, and reaches its peak when we have achieved our goal and satisfied our desire.
Taking a shortcut to a reward
The use of alcohol and other drugs is a shortcut to the release of dopamine. It is also more powerful than natural happiness enhancers. Amphetamines, for example, release ten times more dopamine than good food. With alcohol or cannabis, it is still twice as much.
But dopamine is not the only neurotransmitter involved in drug use. Drinking alcohol activates a variety of neurotransmitters: Alcohol, for example, binds to so-called GABA receptors, which has a sedative effect. Glutamate receptors are blocked, which has a further depressant effect on the body. Alcohol also stimulates opioid receptors, which release endorphins and make you feel good.
Drinking more, more often, permanently changes neurobiology. Studies show that heavy drinking can lead to a reduction in dopamine receptors. Alcohol is then less able to dock on to the reward system, meaning that larger and larger amounts are needed to feel the same effect. This leads to the development of tolerance.
Did the Corona Pandemic create more alcoholics?
During the pandemic, alcohol consumption was a recurring theme in the media. The fear was that people would reach for the bottle more often in isolation. There are still no reliable figures on whether the Corona crisis has led to more alcoholism in Germany or elsewhere in Europe. What we can say, however, is that people who drink a lot on social occasions have tended to drink less in lockups because they have not had the opportunity to go out. Conversely, it is likely that people who were on the wagon before the lockdowns drank alone at home, thus reinforcing the dependency.
The World Health Organization’s ICD-10 defines what constitutes risky use, and the criteria are clinically applicable to all drugs. An addiction syndrome exists when there is a strong craving and loss of control, when tolerance has developed and the body reacts with withdrawal symptoms when the drug is stopped. In addition, when the use is harmful to the person. Physical damage, such as to the liver, can then be well objectified. Social damage includes, for example, the question of whether one’s own behavior is restricted by consumption.
The path to addiction is usually gradual. It can be described as follows: In the beginning, the hedonic effects of alcohol consumption are in the foreground. You drink because it makes you feel good. Gradually – and this is a slower process with alcohol than with harder drugs – everything revolves around the bottle. Alcohol abusers often don’t have much social contact, and nutrition may be neglected. This essentially means that the reward is primarily obtained through alcohol.
Brain volume is lost
People who drink excessively also lose life expectancy. Studies that used brain scans to examine 36,000 people included participants who abstained from alcohol altogether as well as those who drank four or more units of alcohol a day (one unit was defined as about half a glass of beer). Alcohol consumption was found to be associated with a reduction in total brain volume – the more one drank, the more brain volume was lost. Both gray matter, which is made up of nerve cell bodies, and white matter, which is made up of nerve processes, are affected to the same extent.
For example, if a 31-year-old person goes from one unit of alcohol a day to two units a day (the equivalent of about one glass of wine), he or she will show brain changes equivalent to two years of aging. Going from two to three units of alcohol per day is like aging three and a half years.
Memory of addiction persists years after abstinence
Examining the brains of alcoholics to see how they respond to visual stimuli reveals that the prefrontal cortex plays an important role in behavioral control as a mediator between emotion and reason. When a glass of beer is placed in front of an alcoholic, a circuit is set in motion: The reward system kicks in because it is signaled that alcohol may be available. The prefrontal cortex, which is connected to the reward system, then has to work very hard to keep the person from reaching for the glass. In psychology, this is called “top-down control. For alcoholics, this control no longer works. They develop a sensitivity to alcohol-related stimuli, such as smells. Even after years of abstinence, the memory of addiction is present. Confrontation with alcohol-related stimuli can therefore trigger strong cravings and relapse.
You can’t erase the addiction memory, but you can overlay it with new content. This means that stimulus exposure training is done with people who are very sensitive to alcohol stimuli. Subjects are exposed to their favorite drink and, with the help of a therapist, learn not to reach for it. They experience a reduction in their craving for alcohol, even though they do not drink. This works in a similar way to fear-exposure training, where people with an extreme fear of heights, for example, are sent up a skyscraper. The principle is that you have to face your fear in order to overcome it.