“There is less stigma associated with depression, better treatments are available, but depression's link to mortality still persists,” said Stephen Gilman of the Eunice Kennedy Shriver National Institute of Child Health and Human Development.
Researchers analyzed six decades of mental health data on 3,410 individuals during three periods: 1952 to 1967, 1968 to 1990, and 1991 to 2011. They used the data from the Stirling County Study that started in 1952 in Canada. It is also one of the first community-based studies on mental illness. The average age of the participants was around 49 years. For at least 19 years, the researchers followed half of the participants.
During the 60-year period, the team found that young adults with depression at 25 years old had a shorter life expectancy ranging from 10 to 12 years in the first group, while the second and third groups lived four to seven years and seven to 18 years shorter, respectively.
Results showed that the link between depression and early death was shown every decade in men, while it started in the 1990s in women. The risk of death linked with depression was greatest in the years following a depressive episode. This led the researchers to conclude that this risk could be reversed by treating depression.
“Most disturbing is the 50 percent increase in the risk of death for women with depression between 1992 and 2011,” said Ian Colman, Canada Research Chair in the School of Epidemiology, University of Ottawa, Canada.
Changes in the society may have caused the increased risk of death for women who suffer from depression.
“During the last 20 years of the study in which women's risk of death increased significantly, roles have changed dramatically both at home and in the workplace, and many women shoulder multiple responsibilities and expectations,” explained Colman.
Depression has also been associated with unhealthy diet, physical inactivity, smoking, and alcohol consumption, which are all factors that can lead to chronic health conditions. (Related: Depression may Cause Heart Disease and Related Death.)
The researchers noted that their study's limitations include a long gap between participant interviews that hindered them to identify the exact timing of depression and the subjects' experiences of repeated instances of depression between interviews. They also recommended that family doctors should observe patients for mood changes, especially repeated episodes of depression, for them to be able to offer treatment and support.
The study was published in the Canadian Medical Association Journal.
According to the World Health Organization (WHO), depression is the leading cause of poor health and disability globally. Latest records show that over 300 million people around the world are suffering from depression, which is an increase of more than 18 percent from 2005 to 2015.
“These new figures are a wake-up call for all countries to re-think their approaches to mental health and to treat it with the urgency it deserves,” WHO Director-General Margaret Chan said in a press release.
Depression has been linked to different health disorders and diseases. The WHO identified that depression increases the risk of chronic health diseases such as diabetes and heart disease. While people with these conditions are also more prone to being depressed. In addition, depression is a crucial risk factor for suicide.
“A better understanding of depression and how it can be treated, while essential, is just the beginning. What needs to follow is sustained scale-up of mental health services accessible to everyone, even the most remote populations in the world,” Shekhar Saxena, director of the Department of Mental Health and Substance Abuse at WHO, said in the same press release.