Often, when we are feeling sad, we do things that comfort ourselves. This may be eating in excess, staying in bed, or just being alone for a period of time. Some of us seek more immediate means to change our mood, like drinking alcohol, often in excess.
A Yale-Penn study of the genetics of drug and alcohol dependence have led researchers to discover a gene variant in the brain that is strongly associated with the risk of developing both major depression and alcoholism. Most interestingly is that this association was more commonly seen in African American men.
Major depressive disorder is characterized by at least two weeks of low mood and is often accompanied by low self-esteem, loss of interest, low energy, and pain without a clear cause. This disorder can negatively affect a person’s personal, work, and school life. It is estimated that between two and seven percent of those suffering from major depression take their own life, committing suicide.
Alcohol has been consumed by humans for centuries. It is a common celebratory beverage, helps calm our nerves, and can even be healthy for us in moderation. However, drinking too much and being dependent on the substance can lead to detrimental side effects.
The study in question involved over 7,800 men and women of an average age of 40 years. Participants entire genome was analyzed, looking for specific gene variants associated with comorbid alcohol dependence and major depression.
The researchers discovered a replicable genome-wide significant associate gene variant named SEMA3A in a sample of 4,653 African American men. No such association was seen in a sample of 3,169 European American participants.
“The strength of the findings was unexpected—this was a very strong signal,” said Joel Gelernter, the Foundations Fund Professor of Psychiatry and professor of genetics and of neuroscience.
For the time being, researchers aren’t sure what the cause of this gene association is and why it wasn’t found in Europeans. It does, however, enhance the understanding of genetic mechanisms between these two major afflictions.