Depression can shatter your mood, turn your relationships to shit, and leave you in physical pain. Now, research based on 60 years of data suggests that the mental illness doesn't just affect how we live, but also when we'll die: Men and women who have experienced depression are more likely to die early than those who haven't, according to a study published today in the Canadian Medical Association Journal.
For the study, the researchers gathered three separate representative samples of the population, in 1952, 1970, and 1992. Each of the 3,410 people who participated in the study answered questions about their mental health. To be diagnosed as "depressed," they had to exhibit typical signs of a depressed mood as well as changes in their appetite, sleep, and activity. The symptoms must have affected their daily functioning and lasted at least one month.
The interview wasn't a one-and-done deal: The researchers followed up with everyone later on, so that the people who joined the study in 1952 were reinterviewed in 1970 and again in 1992. (The participants from 1972 were also re-evaluated in 1992.) They found a strong link between depression and early death in both men and women. Once someone had been symptom free for 15 years, their risk subsided, but as soon as another depressive episode occurred, it increased again.
The researchers also discovered distinct gender trends. In the first sample, men who were depressed at the time of their interview were almost three times as likely as to die early—10 to 12 years earlier, in fact—as men who were not depressed. The link weakened over time: In the second sample, depressed men were twice as likely to die early, and in the last sample, they were 52 percent more likely to do so. "Among men, the mortality risk associated with depression over the three calendar periods was most pronounced in the study's early years and diminished substantially over time," the authors write.
More From Tonic:
But for women, it's a different story. There was hardly any link between depression and early death for women in the first two samples. That changed in the 1992 group: The risk of dying early for women who were depressed was 51 percent higher than for women who didn't meet the diagnosis. "When we see a pattern like this, where over a long period of time the patients change, it really points you to ask, well, what else changed in the intervening years that could explain this?" says study author Stephen Gilman, an investigator and acting chief of the health behavior branch at the National Institute of Child Health and Human Development.
What's different about life today compared to the 1950s? Gender roles, for one. "Women's roles have changed dramatically in recent decades," says study author Ian Colman, a professor at the University of Ottawa. Today, women carry many more responsibilities at home and at work. That's a huge step in the right direction for gender equality, but it could partially explain why the risk jumped in the 90s. "This may make it more difficult for women to successfully manage difficulties with their mental health."
Also important: The link persisted even after the researchers controlled for risk factors like obesity and smoking and drinking habits. "These factors didn't explain the high risk of mortality in our study," Gilman says. "What we'd like to do over time is to try to understand exactly why this association exists, because that will give us a better idea of where we can intervene." It probably has something to do with depression's connection to other chronic issues like cancer, inflammation, and heart disease, he adds.
Lots of progress has been made since the mid-20th century toward making mental health less of a taboo topic. But the stigma is still very much alive. "Despite major advancements in reducing stigma relating to mental health, the fact remains that a very high proportion of individuals with depression don't seek help," Colman says. It's no small problem: In 2015, an estimated 6.7 percent of adults in the US were living with depression—approximately 16.1 million people. And people still have trouble finding the mental health care that they need, whether it's due to fear or lack of access.
The researchers' results suggest that depression can cut your life short by seven to 10 years, Colman says. "Getting people with depression into care as early as possible results in better long-term outcomes," he adds. "The easiest thing we can do as a society is to support people who are struggling with their mental health and encourage them to reach out for help."
Read This Next: I Thought I Was Depressed But It Turns Out I'm Bipolar