A long-term study on mental health has “strongly linked” depression to a higher risk of early death.
An international team of researchers looked at 60 years of mental health data in a rural Nova Scotia county and compared that data to the Canadian mortality database.
The researchers found that participants with recurrent depression died earlier than usual, in some cases up to 18 years earlier. The reasons for these early deaths isn’t clear.
“We looked at smoking, alcohol abuse and obesity and also educational attainment . . . because we thought those could be factors that might explain this increased risk,” said co-author Stephen Gilman of the Eunice Kennedy Shriver National Institute of Child Health and Human Development in Bethesda, Maryland, which is part of the National Institutes of Health.
But while lifestyle and health factors couldn’t be confirmed, the authors didn’t rule them out, either.
Most of the participants with depression died of the same diseases — cancer and heart disease — that kill people in the general population.
There’s an obvious link between depression and suicide but “very few” of the participants killed themselves, Gilman said.
The Stirling study has tracked the mental health histories of 3,410 county residents since 1952.
The region isn’t identified for privacy reasons. The pseudonym Stirling County was created at the start of the study.
It has become one of the most recognized “longitudinal” mental health studies in the world. Participants have been interviewed, and in some cases re-interviewed, over three periods: 1952 to 1967, 1968 to 1990 and 1991 to 2011.
“In 1952 it represented a sample of the county, just using general population-based survey sampling approaches,” Gilman explained. “And then in 1970 it did two things, it re-interviewed the 1952 participants — and so that’s a typical longitudinal study — but it also drew a new . . . representative sample of the same county.”
The remaining 1952 participants were also re-interviewed in 1992, when another survey sample was started.
“We were able . . . to find out, if they were depressed earlier, are they still depressed. What we found in relation to mortality is that the highest risk of mortality was among the group of participants . . . who had experienced depression over multiple time points in the study.”
That drives home one of the study’s main messages, Gilman said, “which is it’s very important to be vigilant about recurrent (depression) episodes” through long-term monitoring by a health-care provider.