Mental illness is the leading cause of disability in the U.S. The National Institute of Mental Health estimates that those with mental illness live with it for 27 years on average at a cost to the American economy about $79 billion. One of the major reasons mental illness is so disabling is that it can strike a person in the prime of their lives. Many go undiagnosed and without help even if effective treatment exists because of the stigma that surrounds having a mental illness. This leads to family troubles, job loss, and a variety of other personal and social problems.
Fortunately, new ways of approaching this staggering issue are starting to emerge. New research out this week found that it may be soon be possible to identify those likely to develop depression or anxiety years before symptoms appear.
Where did this idea come from?
The researchers observed that people respond differently to stressful life events. Some people, for example, recover from the loss of a loved one while others can fall into a deep depression. The researchers wondered if maybe the way the brain processes emotion and stressful situations had something to do with who was susceptible to mental illness when stress arises.
The team focused on a part of the brain called the amygdala. While the amygdala has often been associated with fear, it also plays a more general role in detecting when a person is in a threatening situation, how they should respond to stress and their ability to learn from negative experiences. The researchers thought that maybe if someone’s amygdala responded more strongly to a stressful situation, they would be more likely to fall into a negative response to stress that could lead to depression or anxiety.
How did the research team test this?
The team gathered a group of college students without a diagnosis of depression or anxiety and scanned their brain with a machine called a functional MRI that can show brain activity in real time. While the scanning was taking place, the researchers showed the students pictures of menacing faces that normally activate the amygdala and watched their brain to see what happened. Once this was done, they followed up with the students every three months and asked them about any stressful life events they had experienced and surveyed them for any signs of symptoms of depression and anxiety. The researchers followed up with the students for up to four years.
What did the research show?
They found that those students whose amygdalas had responded most strongly to the threatening faces were also more likely to have symptoms of depression and anxiety when they experienced a stressful life event. The effect was small. Those students with more reactive amygdalas were only 1 to 5% more likely to have these symptoms. But the researchers say that the effect could be much larger in populations more likely to be at risk for depression and anxiety that are exposed to significant stress much more often.