Here's yet another friendly, scientific reminder that mental health conditions are not within your control. Depression is an illness that can affect your entire body -- potentially on a cellular level, according to a recent study.
Researchers from the University of Granada conducted a meta-analysis of 29 previous studies, where they looked at biomarkers in the cells of people with depression before and after treatment with antidepressants and compared them with a healthy control group. In particular, they looked at levels of malondialdehyde -- a biomarker in the body that indicates cell deterioration and oxidative stress -- finding an association between depression and elevated levels of the compound.
Oxidative stress occurs when the body both overproduces and then struggles to flush out free radicals, which are molecules that can negatively alter proteins, lipids and DNA in the body and trigger a number of illnesses. While it's unknown how depression and oxidative stress are linked, the study indicates a connection between the two.
Before treatment, depressed people had high levels of malondialdehyde and low levels of the antioxidants zinc and uric acid, indicating oxidative stress. But after the patients received treatment, their malondialdehyde dropped so significantly that most treated depression patients' levels were nearly indistinguishable from healthy patients, the researchers found.
The findings indicate that depression "should be considered a systemic disease," according to the researchers. It could also explain the link between depression and other maladies such as cardiovascular disease.
"Results suggest that oxidative stress plays a role in depression and that antidepressant activity may be mediated via improving oxidative stress [and] antioxidant function," the study authors wrote in the conclusion.
Previous research suggests a clear link between a person's mental health and physiological state. Depression may be linked with inflammation and experts believe that the illness could be genetic. Moreover, those with the disorder experience physical symptoms, such as gastrointestinal issues and severe headaches.
Despite these links, another recent study published in the journal Health Affairs found that doctors follow up with patients with depression the least when compared to individuals with other conditions like diabetes or asthma.
Research like this most recent study and the Health Affairs study may play a role in changing the way everyone views mental illness. "The brain and body are connected," Sagar Parikh, associate director of the University of Michigan Comprehensive Depression Center previously told The Huffington Post. "The bottom line is that treating mental health problems not only reduces individual pain but it actually has an impact on physical health."
The results were published in the Journal of Clinical Psychiatry.