Alcoholism Rewires Brain to Change Fear Response
It’s long been known that chronic alcohol abuse changes the way the brain functions. It’s obvious, for instance, that degradation happens in the brains of chronic drinkers. The damage leads to alcoholic dementia, a condition marked by loss of memory, neurological damage and problems with thinking. Scientists have now found a more subtle change in the brain’s wiring from alcohol abuse.
Alcoholics have trouble recovering from stressful events
In a paper published in Nature (abstract here), the changes are outlined. Called, “prefrontal remodeling,” the connections between neurons are changed with long-term exposure to alcohol and the effect is an inability to rebound from stress. For example, when a normal person is subject to fear, the stress response kicks in but then fades over time when the fearful situation is over. This study shows that alcoholics don’t recover as fast or as well.
The result is that alcoholics don’t rebound from trauma, which increases their chances of suffering post traumatic stress disorder (PTSD).
Alcohol affects neuron connections in the brain
The study was done on mice, but the technique is well-understood and applicable to humans. Two groups of mice were trained to fear a certain sound by coupling it with a shock. One group got alcohol and the other didn’t. The non-alcohol treated group learned not to fear the sound after a period of no associated shocks, but the group with alcohol couldn’t seem to lose their fear. Examining the brains of each group showed there were actual changes in the way the neurons were connected.
A vicious cycle
The interesting thing in humans is that stress might cause someone to drink more as a way to relieve it – there’s the movie trope of a shot of brandy after a fearful event to “calm the nerves.” But those who experience chronic fear, such as in a war situation or with domestic violence, and then drink are only setting the fear response more deeply. They will carry the incident past when it should fade. The danger, of course, is a self-fulfilling cycle of drinking because of stress, extending the effects of that stress because of the drinking, and then drinking even more because of that. What a vicious cycle!