More than 20 million people in the United States suffer from depression. It is estimated that around 12 percent of women and 7 percent of men experience some form of depression every year.
A study in 2003 claimed to have found a gene in the neurotransmitter serotonin connected to depression and how people deal with stress. The research was called into question, however, in 2009 by an alternate group of studies that insisted there was no biological link between the gene and depression.
Fast forward to 2010: Researchers at the University of Michigan Medical School have compiled 54 different studies from 2001 to 2010, the largest analysis of its kind, and have found that an individual's genetics do indeed contribute to how they cope with depression.
The findings support the 2003 study by showing that people with a shorter allele (or DNA sequence) on the serotonin gene have a more difficult time dealing with traumatic events and depression.
But a short allele is not the only contributing factor to depression; a variety of other things, such as specific life events or childhood trauma, could play a part as well.
This breakthrough in understanding the biology of mental illnesses such as depression and anxiety could lead to earlier diagnosis and more effective treatments in the future.