Depression less deadly than previously thought

May 16, 2017, University of Amsterdam
Credit: Universiteit van Amsterdam (UVA)

Over three decades of research suggest that depression increases the odds of death. However, a new research paper throws doubt on this presumed link after finding no evidence of a direct association between depression and all-cause mortality. The paper, authored by a research team from Johns Hopkins University, Federation University Australia and the University of Amsterdam (UvA), involved the largest ever analysis on the topic and is published in the latest edition of World Psychiatry.

Since the 1980s, numerous studies have appeared which suggest a high risk of mortality among people suffering from . This has generally been taken as evidence that depression directly causes . As part of their study, researchers Beyon Miloyan and Eiko Fried re-evaluated this supposed link by reassessing 293 studies derived from 15 systematic reviews. The studies in question comprised over 3.6 million participants and 400,000 deaths.

Despite the widespread suggestion that depression leads to more death, at least 95 percent of the studies the researchers investigated were found to be of insufficient quality. Using quantitative and qualitative methods, the researchers identified a pronounced publication bias. Specifically, studies that identified the largest associations between depression and mortality featured small samples, a low number of deaths, and short follow-up periods. Moreover, the researchers discovered that only about 5 percent of the 293 studies adjusted their statistical models for other like anxiety or substance use problems, which are very common among : comorbidity rates exceed 50 percent.

The researchers also found that two-thirds of the studies comprised respondents who were pre-selected on the basis of medical conditions. Many symptoms of depression like insomnia and fatigue are shared with various physical conditions or may arise as side effects of medications used to treat existing disorders. This, say Miloyan and Fried, could lead to the conclusion that depression is the cause of death, even though death may be better attributed to preexisting illnesses. To eliminate this confound, one solution is to properly control for comorbid psychological and physiological conditions, another to specifically study depressed patients without pre-existing physical illnesses.

'The studies we looked at have over the years led many people to place too easily, and perhaps mistakenly, a lot of confidence in the notion that depression is directly to blame for the high mortality', says Miloyan, a researcher at Johns Hopkins University and faculty member at Federation University Australia. 'In fact, when we look more closely at the data from the few studies that are of acceptable quality, we do not find convincing evidence that depression is directly associated with all-cause mortality.'

Instead, the results suggest that other variables, more specifically health behaviours and comorbidity, might be related to the higher rate of mortality among depressed individuals. 'For example, it is known that depression goes hand in hand with unhealthy lifestyle behaviours such as smoking, drinking and physical inactivity', says Fried, a psychologist and postdoctoral researcher at the UvA. 'Smoking in particular is associated with an increased risk of developing depression and with many causes of death. Such complex interactions among variables associated with depression and death, which have been largely ignored in the literature, imply that it is premature to draw strong causal conclusions.'

Miloyan and Fried hope their findings encourage other researchers to investigate this question more carefully before designing and implementing programmes and policies aimed at curbing depression in order to substantially reduce deaths. Miloyan: '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.'

Explore further: Mortality risk in T2DM increased with depression and/or anxiety

More information: Beyon Miloyan et al. A reassessment of the relationship between depression and all-cause mortality in 3,604,005 participants from 293 studies, World Psychiatry (2017). DOI: 10.1002/wps.20439

Related Stories

Mortality risk in T2DM increased with depression and/or anxiety

January 16, 2017
(HealthDay)—For individuals with type 2 diabetes, anxiety symptoms affect mortality risk, independently of depression symptoms, and attenuate the excess mortality associated with depression, according to a study published ...

Mortality up with depression just before breast cancer diagnosis

April 14, 2017
(HealthDay)—Women with newly-developed depression before a breast cancer diagnosis have a modestly, but significantly, increased risk for death, according to a study published online April 7 in Cancer.

Anxiety and depression are common in people with epilepsy

May 4, 2017
An analysis of published studies found that in individuals with epilepsy, there is a 20.2 percent prevalence of anxiety disorders and a 22.9 percent prevalence of depression. Investigators also found no differences in the ...

Changes in depression symptoms tied to mortality in lung cancer

October 7, 2016
(HealthDay)—Longitudinal changes in depression are associated with differences in mortality among patients with lung cancer, according to a study published online Oct. 3 in the Journal of Clinical Oncology.

The heterogeneous nature of depression

October 25, 2016
Depression is generally considered to be a specific and consistent disorder characterised by a fixed set of symptoms and often treated with a combination of psychotherapy and medication. However, the standard rating scales ...

Combo of diabetes, depression increases post-MI mortality

February 27, 2012
(HealthDay) -- Having both diabetes and depression significantly increases the risk of dying in the years following a heart attack, beyond the increased risk from either condition alone, according to a study published in ...

Recommended for you

People are more honest when using a foreign tongue, research finds

August 17, 2018
New UChicago-led research suggests that someone who speaks in a foreign language is probably more credible than the average native speaker.

FDA approves brain stimulation device for OCD

August 17, 2018
(HealthDay)—A brain stimulation device to treat obsessive-compulsive disorder (OCD) has received approval for marketing Friday by the U.S. Food and Drug Administration.

Research eyes role of stress in mental illnesses

August 17, 2018
We all face stress in our lives. Even researchers seeking to understand why some people shrug it off while others face battles against disorders like depression or PTSD.

16 going on 66: Will you be the same person 50 years from now?

August 17, 2018
How much do you change between high school and retirement? The answer depends on whether you're comparing yourself to others or to your younger self.

Men and women show surprising differences in seeing motion

August 16, 2018
Researchers reporting in the journal Current Biology on August 16 have found an unexpected difference between men and women. On average, their studies show, men pick up on visual motion significantly faster than women do.

Expecting to learn: Language acquisition in toddlers improved by predictable situations

August 16, 2018
The first few years of a child's life are crucial for learning language, and though scientists know the "when," the "how" is still up for debate. The sheer number of words a child hears is important; that number predicts ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.