WEDNESDAY, July 6, 2011 (HealthDay News) -- People who experience serious adversity early in life and those who've had prior episodes of depression become more easily depressed than others when confronted with relatively minor misfortunes, researchers say.
Previous research has found that about 30 percent of people with first-time depression and 60 percent of those with a history of depression develop the disorder after a negative event that most people would be able to shake off.
"We have known for a long time that some people are more likely to experience mental and physical health problems than others," George Slavich, an assistant professor at Cousins Center for Psychoneuroimmunology at the University of California, Los Angeles, said in a university news release.
"For example, while some people get depressed following a relationship breakup, others do not. In this study, we aimed to identify factors that are associated with this phenomenon and to examine whether increased sensitivity to stress might be playing a role."
This new study included 26 men and 74 women with depression who were interviewed about adverse events they experienced when they were young, how many times they'd had depression, and recent stressful situations.
Slavich and colleagues found that fairly low levels of recent life stress could trigger depression in people who lost a parent or who had been separated from a parent for at least one year before age 18, and in people who had experienced more episodes of depression over their lifetime.
The study, published in a recent online edition of the Journal of Psychiatric Research, raises the question of how adversity early in life and prior depression increase sensitivity to stress.
It may be that people who experience early adversity or repeat bouts of depression develop negative beliefs about themselves or the world, and these beliefs take over in subsequent stressful situations, the researchers suggested.
Or it could be that early adversity and depression have a biological effect that lowers the threshold at which depression is triggered, they added.
The U.S. National Institute of Mental Health has more about depression.