A recent study published in the Journals of Gerontology has confirmed that both men and women who have at least one major depressive episode have a significantly higher mortality risk. Moreover, this risk has progressively increased for women.
Depression is one of the most widespread mental disorders among adults in the United States. According to data provided by the National Institute of Mental Health, 6.7 percent of all U.S. adults had at least one major depressive episode in 2015 alone. A major depressive episode, as defined by the Diagnostic and Statistical Manual of Mental Disorders, occurs when five or more of the following symptoms are consistently present for a period of 2 weeks: depressed mood, loss of pleasure in normally pleasurable activities, abnormal weight loss or weight gain, sleeplessness or oversleeping, abnormal physical agitation or slowness, fatigue, feelings of guilt or worthlessness, lack of focus, and “recurrent thoughts of death.”
The study shows adults 50 and older who suffer from major depression face a 43 percent increase in the risk of death, especially cardiovascular disease or cancer.
“There’s a major link between major depression and mortality. Taking all these other health behaviors out of it, you can continue to find this unique relationship between depression and mortality,” said Jarron M. Saint Onge, a KU assistant professor of sociology and the study’s lead author. “There’s something that’s leading to early death. And that’s taking out smoking, taking out exercise, all these behavioral factors that would explain it.”
For the mortality data, researchers examined the 1999 National Health Interview Study linked to the 2006 National Death Index, which included a sample size of 11,369 adults respondents ages 50 and older, of whom 2,162 have died from non-suicide or accident related deaths. To measure major depression, they used data derived from the World Health Organization’s Composite International Diagnostic Interview Short-Form, or CIDI-SF, which is generally accepted as an accurate measure of major depression.
Saint Onge said the study’s findings are significant because they suggest that the relationship between depression and mortality is not due solely to people smoking or exhibiting unhealthy behaviors or experiencing chronic conditions that contribute to a higher risk of mortality.
When the researchers adjusted for factors such as marital status, education, employment status, family income, alcohol consumption, level of physical activity, smoking status, body mass, functional limitations and chronic conditions, they still found an independent association among major depression and increased risk of non-suicide mortality among the age group.
This includes findings that major depression was associated with 2.68 times the risk of cardiovascular disease mortality among those who did not have cardiovascular disease at the baseline.
“What we’re finding here is it’s important to be vigilant to find depression among people older than 50 because of a host of reasons,” Saint Onge said. “It’s important because of its relationship with health-compromising behaviors, but it’s also important because it stands as an independent risk factor in mortality. There might be something unique about depression, taking aside all of your other behaviors, that there’s something about depression that might lead to an increased risk of mortality.”
He said related research has suggested major depression may have a physiological effect on blood pressure or arterial tightening that can cause cardiovascular disease.
“It’s physiologically important, but it’s also socially important to think of depression as a risk factor for death as well,” he said.
Also another study recently published in the Canadian Medical Association Journal, Ontario, Canada confirmed major depressive episodes as a significant risk factor of early death for both men and women.
“There are fewer stigmas associated with depression, better treatments are available, but depression’s link to mortality still persists. At first, the association was limited to men, but in later years it was seen for women as well,” the study shows. The team analyzed data sourced from 3,410 adults from Atlantic Canada enrolled in the Stirling County Study, which focused on gaining a better understanding of various mental illnesses.
In the current research, the authors were interested in seeing to what extent depression was linked to a heightened mortality risk, and whether this risk was different for men versus women.
They conducted their study over 60 years, analyzing data from participants enrolled during three distinct periods: 1952–1967 (1,003 participants), 1968–1990 (1,203 participants), and 1991–2011 (1,402 participants). The participants’ mean age at the time of enrollment was 49 years.
This information was also linked to death records from the Canadian Mortality Database.
A strong connection between a diagnosis of depression and a significantly increased risk of mortality was noted for men across all three periods. For women, however, a link between depression and risk of death was only observed from the 1990s onwards.
Moreover, the team reports that the most severe risk of death follows a depressive episode, but also that this risk might be counteracted by an improvement in the individual’s mental health.