Alcohol abuse is an ongoing problem throughout the United States. 5.3 percent of people ages 12 and older, or 14.5 million people, report having trouble controlling their drinking. Understanding what causes alcohol addiction is a key part of reducing the rates of alcohol abuse across the country. How does someone develop a problem with their drinking?
Current research suggests that alcohol abuse is caused by a combination of biology and environment. A person’s genetic makeup takes partial responsibility and their environment takes the other portion. Some developmental factors, such as the age the person started drinking, also play a role in problematic alcohol use.
There’s still plenty of grey area surrounding whether someone will abuse alcohol or not. Not everyone who drinks heavily progresses past this point. They can still choose to stop when they want. What makes some people more predisposed to developing a problem with alcohol abuse?
Researchers in the United States and Sweden are looking for answers to this question. They’re making progress in the understanding of alcohol abuse by looking at postmortem brain tissue from humans and mirroring their studies in rats.
Recently, researchers discovered that rats who develop an addiction to alcohol have an impaired signaling mechanism in their brain. This area, responsible for processing emotions, appears to be faulty in both humans and rats. Humans and rats who share this flawed mechanism are more likely to develop an alcohol addiction.
When operating properly, the mechanism clears a substance called gamma-Aminobutyric acid (GABA) away from the amygdala. The amygdala is responsible for learning, memory, motivation, and emotion. When the mechanism is faulty, though, it fails to clear GABA from this region. As a result, too much GABA around the amygdala inhibits proper neural signaling.
According to the authors of this study, about 10 to 15 percent of people exposed to alcohol “develop alcohol-related problems.” The percentage of rats exposed to alcohol who developed problems reflected a similar rate of 15 percent.
Rats who continued to dose themselves with alcohol behaved similarly to humans who exhibit the same behavior. The rodents in the study kept using alcohol even when presented with an alternative. They experienced negative consequences as a result of using alcohol but continued to dose themselves.
Markus Heiling, the senior study author from the Linköping University in Sweden, explained, “We have to understand that a core feature of addiction is that you know it is going to harm you, potentially even kill you, and nevertheless something has gone wrong with the motivational control and you keep doing it.”
This problem with motivational control seems to be a driving force behind both rats in studies and people in real life who abuse alcohol. Researchers looked to the brains of these rodents to determine what causes alcohol addiction. They found the biggest differences in the amygdala region of the brain.
A protein called GAT-3 is responsible for clearing GABA away from the amygdala. The brains of rats who continued dosing themselves with alcohol showed much lower levels of GAT-3 than their counterparts. Researchers realized that this low concentration of GAT-3 caused a buildup of GABA and was likely related to the rats’ problematic alcohol use.
To double-check their findings, researchers silenced the GAT-3 in rats who chose the alcohol alternative. They found that silencing the GAT-3 led these rats to behave similarly to the other rats who kept choosing alcohol; they started choosing alcohol instead of the sugar water alternative.
Swedish researchers looked to researchers at the University of Texas at Austin for further confirmation. Texas researchers found that postmortem human brain tissue mirrored the rodent studies in Sweden. They found that individuals with “documented alcohol addiction” also had low GAT-3 levels, much like the rats.
The connection between low GAT-3 levels and the clearing of GABA gives researchers a new direction to head in. Though there is still a wide range of factors that determine whether someone develops a problem, their findings offer some hope. Overcoming drinking problems can be a great challenge for many people. Researchers hope that by more closely identifying causes of alcohol addiction, clinicians will be able to better treat these individuals. The more tools and resources a person has to help them control their drinking, the more likely they are to find relief from alcohol addiction.