No direct association between depression and all-cause mortality, says study

Depression is increasingly being associated with greater rates of mortality. Major depression is one of the most common mental health disorders in the United States. According to the National Institute of Mental Health (NIMH), in 2015, more than 16 million people aged 18 years or older, representing 6.7 percent of all adult population, had at least one major depressive episode in the previous year.

While scientific studies done in the past few decades suggest depression to be an increasing cause of mortality, a new research states otherwise. Researchers from the Johns Hopkins University, the University of Amsterdam and the Federation University Australia re-analyzed 293 studies derived from 15 systematic reviews. The studies involved over 3.6 million participants and 400,000 deaths.

The purpose of the research, published in the journal World Psychiatry on May 12, 2017, was to understand the features of studies that address the depression-mortality relationship and to outline some practical reasons for diversity between studies. Besides, the researchers wanted to explore whether evaluations done on the relationship between depression and mortality on the basis of most rigorous studies differed from evaluations of previously done meta-analyses.

According to Beyon Miloyan, researcher at the Johns Hopkins University and faculty at the Federation University Australia, while the studies conducted over the years have led people to believe that depression is directly to blame for high mortality, the evidence collected over the years is not convincing enough to directly link depression with all-cause mortality. Instead, the research results prove other variables including health behaviors and existence of one or more additional disorders to be related to higher rates of mortality among depressed individuals.

95 percent studies found worthless

The researchers found at least 95 percent of the studies to be insufficient and of not good quality. Only 5 percent of the studies adjusted for at least one comorbid mental health condition. That is, out of the total studies analyzed, the researchers discovered only about 5 percent to adjust their statistical models for other mental health conditions, including anxiety and substance use problems. They concluded that symptoms of depression, including insomnia and fatigue, were common with many physical conditions or may have developed out of the negative side effects of medications used to treat existing disorders.

In addition, there appeared to be a pronounced publication bias as the largest estimates came from studies involving small samples, low number of deaths and brief follow-up periods. Post their analysis, the researchers pointed out that given the overall poor quality of available evidence, they were unable to draw a solid conclusion about the relationship between depression and mortality.

Authors of the new study hope that their findings encourage other researchers to investigate the question more carefully before designing and executing policies and programs aimed at treating depression. “This isn’t to suggest that depression shouldn’t be treated, of course, but rather that as far as the cause of overall mortality is concerned, the key factors probably lie somewhere else and warrant more rigorous future research,” said Miloyan.

Road to recovery

While depression has often been linked to high death rates, the new research proves that the key factors affecting the cause of overall mortality probably lie somewhere else and requires rigorous research. Though depression is a serious mental health problem in the U.S., it can be treated with timely medical intervention.

If you or someone you know is suffering from any mental health disorder, it is imperative to seek professional care at a certified treatment facility. For more information on mental health and mental disorders, get in touch with mental health experts at the 24/7 Mental Health Helpline. Call us at our 24/7 helpline number 855-653-8178 or chat online to know mental health centers near you.