According to the Centers for Disease Control and Prevention, around 1 in 10 American adults report having some form of depression. Now, researchers have revealed an unlikely strategy for treating the condition; activating neurons in the brain associated with stress-induced depression may actually trigger natural resilience to it.
The research team, led by Allyson K. Friedman, PhD, of the Icahn School of Medicine at Mount Sinai in New York, NY, says their research could lead to new targets for "naturally acting antidepressants."
To reach their findings, recently published in the journal Science, the researchers conducted a study on mice that were susceptible to depression.
The team says mice that are resilient to social defeat stress - a form of stress triggered by losing a dispute or from a hostile interaction - currents in the cation channels, or ion channels, of the brain are significantly increased, compared with depressed or control mice. The cation channels are responsible for transporting positive ions in dopamine neurons.
For their latest study, the researchers wanted to see whether increasing currents in the cation channels of mice susceptible to depression would enhance their resilience and coping mechanisms.
Brain performs a 'complex balancing act' to become resilient to depression
The investigators exposed the mice to optogenetics. This involves using laser optics and gene virus transfer to control the signaling of dopamine neurons.
Increased activity of dopamine neurons in mice allowed them to cope with stress without developing symptoms of depression.
They found that increasing such activity allowed the mice to cope with stress without developing symptoms related to depression. Furthermore, they were amazed to find that the hyperactivity of the dopamine neurons normalized.
"To our surprise, we found that resilient mice, instead of avoiding deleterious changes in the brain, experience further deleterious changes in response to stress, and use them beneficially," says senior study author Ming-Hu Han, PhD, also of the Icahn School of Medicine at Mount Sinai.
Friedeman explains that in order to achieve this resilience when under social stress, the brain must perform a "complex balancing act," which involves negative stress-related changes in the brain activating positive changes.
The team says their findings may lead to the development of new antidepressant medication. They add that if a drug could boost the resilience and coping mechanisms of individuals susceptible to depression, it may have fewer side effects and could tackle depression in a more natural way.
Commenting on the team's findings, Dr. Eric Nestler, of the Icahn School of Medicine - who was not involved in the study - says:
"In this elegant study, Drs. Friedman and Han and their colleagues reveal a highly novel mechanism that controls an individual's susceptibility or resilience to chronic social stress.
The discoveries have important implications for the development of new treatments for depression and other stress-related disorders."
Earlier this year, Medical News Today reported on a UK study that revealed the discovery of the first biomarker that may predict clinical depression in teenage boys.