Alcohol addiction: could the brain’s immune system be the key to understanding and treating alcoholism?
Alcohol abuse is a serious problem worldwide. In England alone, over 350,000 alcohol-related hospital admissions – and over 5,000 alcohol-related deaths – were reported in 2018. Long-term alcohol abuse can have many harmful effects on our body. But one of the organs most affected by alcohol is the brain. Even moderate consumption changes brain structure and leads to cognitive issues, such as declines in memory and problem-solving.
Alcohol use is habit forming and can eventually lead to alcoholism. And though there are many treatments available for alcoholism, research shows these interventions often fail – with less than 20% of patients remaining alcohol free after intervention. Like every addiction, alcoholism is a disease and not a choice, so finding the root cause of it will make treatment easier.
Although genetics and the environment you live in are known to play a role in developing alcoholism, these factors don't tell us how dependence occurs.
However, past research has found hints that the brain's immune system cells (known as microglia) may be involved in addiction, including to cocaine and tobacco). One study even found that alcohol exposure and withdrawal in rats increased microglia numbers in the brain, before any other signs of alcohol-induced decline.
Another two recent studies have investigated brain changes seen in people and animals with alcohol dependence. Each of these studies found a common culprit: inflamed microglia.
Microglia are the brain's resident immune system cells. Their main role is to guard and maintain balance in the brain. When microglia detect a threat, they respond by becoming inflamed and attacking. Normally, they return to normal after the threat is gone, but sometimes when inflammation becomes uncontrollable – such as with Alzeimer's disease – it can lead to brain degeneration.