Study links depression to gene-environment interaction
Researchers have used brain scans to demonstrate how people with a certain version of the serotonin transporter gene could be more likely to suffer from depression in times of high stress. The study, which is partly funded by the EU's Sixth Framework Programme, is published in the Online Early Edition of the Proceedings of the National Academy of Sciences. Breakdowns in the serotonin system are implicated in a range of mood disorders, such as depression, suicidality and other negative emotional traits such as neuroticism and harm avoidance. However, the picture is complicated by the interaction of environmental factors, such as stress, with genes. Previous studies have shown that people with the 'short' version of the serotonin transporter gene are more likely to suffer from depression in response to stressful life events than people with the 'long' version of the gene. The team of American and German scientists used functional magnetic resonance imaging (fMRI) to measure blood flow in areas of the brain which are linked to depression and stress, such as the amygdala. Until now it had been suggested that people with the short version of the gene overactivated the amygdala in response to emotional stimuli. Instead, the team found that the amygdala of people with the 'short' version of the gene was overactivated in its resting state, particularly in people with high levels of life stress. The researchers suggest that the higher resting activation state of the amygdala could lead to a chronic state of vigilance or threat in those with the short version of the gene. The research sheds new light on why stressful situations and events lead to depression in some and resilience in others. The research is released in the same week as World Mental Health Day. Another piece of research, from the Karolinska Institute in Sweden, suggests that depression is costing Europe €118 billion a year and a reduced quality of life for 21 million people. In his doctoral thesis, entitled 'Health Economics of Depression,' Patrik Sobocki notes that a great deal of money could be saved by ensuring patients are treated quickly and fully. This would enable them to return to work and have fewer health care visits, as well as improving their quality of life.
Countries
Germany, Sweden, United States