Alcohol addiction increases anxiety disorders.A new study is further cementing the link between alcohol abuse and anxiety problems. The latest research in mice shows that alcohol scrambles certain connections in the brain and makes it harder for alcoholics to recover after a traumatic event.
This explains the well documented link between alcoholism and disorders like PTSD. While traumatic events can effect anyone, those with alcohol problems often find it much harder to recover.
"There's a whole spectrum to how people react to a traumatic event," said study author Thomas Kash, PhD, assistant professor of pharmacology at the University of North Carolina School of Medicine. "It's the recovery that we're looking at - the ability to say 'this is not dangerous anymore.' Basically, our research shows that chronic exposure to alcohol can cause a deficit with regard to how our cognitive brain centres control our emotional brain centres."
The study, which was published by Nature Neuroscience, tested the effects of alcohol on mice. For one month, a group of mice was given a dose of alcohol equivalent to twice the legal driving limit in humans while another group of mice received no alcohol.
Mild electric shocks were then used to get the mice to fear a certain sound. Once the mice were scared of the sound, researchers started playing the feared noise without administering a shock. The alcohol free mice soon learned not to fear the sound, while the alcoholic mice continued to freeze in fear every time the tone was played.
When scientists compared the brains of the two sets of mice after the trial, they found some startling differences. They traced the increased anxiety in the alcoholic mice to differences in the brains circuitry. The alcoholic mice had nerve cells in the prefrontal cortex that were shaped differently to the alcohol free mice. The alcoholic mice also had suppressed NMDA receptors. Researchers believe that if this difference exists in humans it could explain anxiety disorders in humans.
"A history of heavy alcohol abuse could impair a critical mechanism for recovering from a trauma, and in doing so put people at greater risk for PTSD," said NIAAA scientist Andrew Holmes, PhD and the study's senior author. "The next step will be to test whether our preclinical findings translate to patients currently suffering from comorbid PTSD and alcohol abuse. If it does, then this could lead to new thinking about how we can better treat these serious medical conditions."