Genes play a large role in determining physical characteristics like gender and eye color. They also have a hand in determining a person's vulnerability to a particular health condition. While scientists do not know the exact mechanism that triggers disorders like depression and anxiety, it is likely that the right combination of environmental, biological and genetic factors must be in place to trigger their onset. Understanding the role that genetic factors play in these mental health conditions may ultimately lead scientists to a cure.
Gene Variation and Anxiety
Scientists have recognized for years that anxiety disorders tend to run in families and have speculated that gene interaction plays a part. In 2008, researchers at Massachusetts General Hospital and scientists at the University of California at San Diego and Yale University studied the role of gene variation and anxiety. The published results are in the March 2008 issue of the Archives of General Psychiatry, and summarized findings appear on PsychCentral's website.
Blood samples, magnetic resonance imaging, personal interviews and questionnaire analysis led this group to discover a particular genetic variation linked to inhibition or introverted behavior. They discovered that participants with introverted/inhibition genes or alleles also experienced increased neurotransmitter receptor activity in the amygdala and the insula. These are parts of the brain involved in the emotional processing of fear and anxiety.
Twin Studies Link Depression to Genetics
Much of the accepted truth regarding genetic factors and depression is based on studies of identical twins. Twins are very helpful in scientific studies because they possess exactly the same DNA genetic code. When one identical twin becomes depressed, the other will also develop clinical depression approximately 76 percent of the time. Identical twins raised separately will both only become depressed 67 percent of the time, suggesting a strong genetic influence. Because twins do not both become depressed 100 percent of the time confirms the notion that other factors, such as the environment and biology, also influence depression. While genetics may make a person more vulnerable to depression, experiences such as traumatic events, substance abuse and even medical illnesses play a major role.
Pediatric Anxiety and Late Onset Depression
Anxiety disorders diagnosed during childhood may be a risk factor for later onset of depression in those children with a family history of moderate to severe depression. A three-generation study looked at 161 children and their parents and grandparents. Reported in the 2006 Archives of General Psychiatry and summarized on the Johns Hopkins Health Alert website, the results indicated that 60 percent of the children with a family history of depression had at least one psychiatric disorder themselves. Anxiety disorders were chief among these disorders, leading researchers to stress the importance of early intervention and treatment of anxiety disorders coupled with generational history.
