Study: Handling stress may be a matter of 'Y'

All people don't deal with stress the same way. And a new study suggests there may be a biological reason for that. The research, published Monday in the Archives of General Psychiatry, finds the more neuropeptide Y (NPY), you have in your brain, the better you are likely to handle stress.

Researchers classified those participating in the study as having low, medium, or high amounts of NPY. When presented with a negative word – “murder” for instance – those with low amounts of NPY showed a lot of activity in the prefrontal cortex, a part of the brain involved in processing emotions. Those with high amounts of NPY showed less activity in that region, as measured by an MRI.

“This tells us that individuals with the risk-associated NPY gene variant tend to activate this key brain region more than other people, even in the absence of stress and before psychiatric symptoms are present,” says the study’s lead author, Dr. Brian Mickey, in a written statement.

A similar experiment using physical pain instead of a negative word showed similar results. When researchers injected a saline solution (salt water) into subjects' jaws to create moderate pain for about 20 minutes, those with lower levels of NPY reported being more emotionally affected, both by the pain itself and by the anticipation of the pain beforehand.

Could the greater emotional impact of stress also lead to higher rates of depression? To test that idea, scientists looked at the amount of NPY in a group of individuals with major depressive disorder. Many of those in that depressed group also had low levels of NPY.

“We’ve identified a biomarker – in this case genetic variation – that is linked with increased risk of major depression,” says the study’s senior author Dr. Jon-Kar Zubieta, in a written statement. “This appears to be another mechanism, independent of previous targets in depression research, such as serotonin, dopamine and norepinephrine.”

This research contributes to what many call the future of health care: Personalized medicine. “These are genetic features that can be measured in any person,” says Mickey. “We hope they can guide us toward assessing an individual’s risk of developing depression and anxiety.”

While the results could contribute to a new antidepressant someday, the study's findings do little to help those currently suffering from depression.

“Nobody has ever found one single abnormality that every depressed person shares. It’s not that kind of illness. There’s literally thousands and thousands of pathways that interact with each other in wildly complicated ways,” says Dr. Charles Raison, CNNHealth's Mental Health expert and an associate professor of psychiatry and behavioral sciences at Emory University. “It’s not the case that every person who has low levels of NPY will be depressed, nor that every depressed person will have low NPY.”

The research was led by a team at the University of Michigan and included 181 participants.