Depression is a debilitating condition that affects some people for short periods of time, while it affects others for years. The Center for Disease Control and Prevention says depression and anxiety are two major causes of Americans dying and contracting illnesses. Overall quality of life goes down, the desire to socialize decreases and forms of disability set in.
There are many debates on what exactly causes depression. Some psychologists say environmental factors can trigger it. Others say it relates to how particular people relate to life. Some scientists say there is a genetic cause for this. A recent study is now indicating that a discovered rogue gene may be linked to causing depression.
The Rogue Gene
Scientists from Washington University Medical School in St. Louis have been working with researchers at Kings College London. Their aim has been to find a gene that makes some people more likely to be depressed than others.
They studied 91 families in Australia and 25 in Finland. They noticed that siblings who suffered from depression had the same genetic variations in certain areas of their DNA. The area they pinpointed is a chromosome known as 3p25-26. This area contains 40 genes, and the scientists believe one or possibly more of these genes cause depression. When two or more members of the same family had depression, they noticed similarities in this genetic region.
Gerome Breen from the Institute of Psychiatry at Kings College headed the study. Breen says, “These findings are truly exciting as possibly for the first time we have found a genetic locus for depression. Though these findings will not result in a test for depression, they will help us track down specific genes that are altered in people with this disease.”
He believes that by understanding this gene, better therapies can be created in 10-15 years.
The Serotonin Gene
Previous research has suggested that low levels of serotonin in the brain can cause depression. Serotonin is a chemical that helps people relax.
A study was done in 2003 with 800 people. Researchers examined people whose genetics made their serotonin transporters less functional. They noticed that those with this genetic condition were more likely to respond adversely to stressful situations and develop depression.
This study, however, was counteracted in 2009. Researchers pulled together 14 studies and found that people with less functioning serotonin transporters didn’t have a higher risk for depression than people who had better functioning transporters.
This seesaw research took another turn when scientists from the University of Michigan found that serotonin transporters may actually play a key role in depression after all.
They analyzed the results of 54 studies, which had data on almost 41,000 people. They found that people with less functional serotonin transporters actually are at higher risk of responding badly to stress and becoming depressed. Dr. Srijan Sen is a professor of psychiatry at the University of Michigan and was the lead in the research. He says if only 14 studies are analyzed, there doesn’t seem to be a link. It’s only when its expanded to 54 studies that the link becomes more clear.
Dr. Srijan Sen says, “One of the hopes I have is that we can settle this story and move on to looking more broadly across the genome for more factors related to depression.”
Environmental and Behavioral Causes of Depression
While a lot of research is done on the genetics of depression, other studies also indicate that environmental factors can trigger depression. These can include things like traumatic incidents, separations and other large-scale changes in life.
Some researchers also say that depression may be caused by “learned helplessness.” When a person is constantly experience traumatic events or stressful situations, they may begin to develop feelings of helplessness. This feeling can be then constantly re-enforced and strengthened through habitual thinking patterns. The study that backs this was done with animals, but the researchers believe this is also applicable to humans.
Causes of Depression: Statistics from the CDC
Causes of Depression: Rogue Gene
Causes of Depression: Serotonin Transporter
Causes of Depression: More on the Transporter
Causes of Depression: Learned Helplessnes