Researchers have long known there was a link between genetics and alcoholism, but the exact genes involved are still being discovered. A recent study, published in Psychiatric Genetics and undertaken by researchers at the University College London in the U.K., has found a rare gene variant that could increase the risk of a person developing alcoholism, as well as schizophrenia and bipolar disorder.
Variant of the GRM3 Gene
The study found that a variant in the GRM3 gene, which occurs in about 1 in 200 people, could increase the risk of alcoholism and other mental health disorders.
In the study, those who had this particular variant were 2-3 times more likely to develop an addiction to alcohol or schizophrenia, and a previous study found it also tripled the risk of bipolar disorder.
For the study, the researchers studied the genes of 6,280 participants, of which 4,971 had been previously diagnosed with alcoholism, bipolar disorder or schizophrenia. They compared the results of their analysis to the 1,309 healthy control participants.
The analysis showed that having a variant of the GRM3 gene increased the chances of developing the condition. The findings as related to schizophrenia were confirmed by a global study that was part of a consortium involving over 200 institutions, including the University College London.
What does the GRM3 Gene Do?
Scientists believe the GRM3 gene is connected to brain signaling. It plays a role in creating the calcium channels used to control the brain cell activation by neurotransmitters, including glutamate and dopamine.
There are two different glutamate receptors, ionotropic that produce fast reactions and metabotropic that produce slower and longer-lasting reactions. The GRM3 gene encodes the metabotropic glutamate receptor 3, which are activated by the neurotransmitter glutamate and are linked to the inhibition of further glutamate release.
A mutation in the gene could change the protein encoding and disturb the transmission of glutamate, which would in return affect certain signaling within the brain. It could also alter how certain chemicals, such as alcohol, affect a person.
Glutamate and Alcoholism
Previous research has found that changes in the brain chemistry, namely to the neurotransmitters, caused by the chemical effects of alcohol contribute to the development of dependency upon the substance.
The most sensitive neurotransmitters and signaling systems to the effect of alcohol include glutamate, serotonin, y-aminobutyric acid (GABA) and dopamine.
The changes to these systems contribute to the behavioral changes associated with alcohol abuse and dependency, including anxiety, sensitivity to stress, and more. The changes in dopamine and glutamate systems have been found to play a significant role in the development of dependence of any addictive substance.
The Future of Alcohol Treatment
This study provides information to help develop new and more personalized treatment options for addiction and the other mental health disorders. Drugs can be developed that will target the gene variant rather than just focusing on curing the symptoms of the disease.
Additionally, by recognizing this gene variant and its relationship with alcoholism, people can be screened for their genetic predisposition to alcoholism. Those with the variant can be more careful about taking preventative measures for avoiding the development of the disease.
This study demonstrates the connection that brain chemistry has not only to the development of addiction but also to other mental health conditions. It could also provide some explanation as to the high rate of comorbidity between mental health disorders and alcoholism.
As more and more studies continue to find genetic clues to the development of addiction, as well as the changes in the brain caused by or contributing to the development of addiction, better treatment options can be developed.