In the interns, as Sen and his team have shown in previous work, depressive symptoms increased dramatically (126%) during the stressful year of training that includes long and irregular work hours — often in environments far from friends and family.
In the widows and widowers, depressive symptoms increased 34% over their pre-widowhood scores. This correlates with past research showing loss of a spouse can be one of the biggest stressors in a person’s life, Cleary said.
A crossover effect
Then, the researchers factored together the depression symptom findings with each person’s polygenic risk score for depression, and their individual responses to questions about connections with friends, family and other social supporters.
Most of the interns lost social support from their pre-internship days – which fits well with the common experience of leaving the place where they attended medical school and going to a new environment where they may not know anyone.
Interns who had the highest polygenic risk scores and also lost social support had the highest scores on measures of depression symptoms later in the stressful intern year.
Those with the same high level of genetic risk who gained social support, though, had much lower depressive symptoms. In fact, it was lower than even their peers with low genetic risk, no matter what happened to their social support. The researchers call this a “crossover effect.”
Unlike the interns, some widowed individuals reported an increase in social support after the loss of their spouse, potentially as friends and family reached out to offer help or just a listening ear.
But the crossover effect was visible in them, too. Widows with high genetic risk for depression who gained social support showed a much smaller increase in depressive symptoms than their peers with similar genetic risk who lost social support after losing a spouse.
There were also some widows who lost social support or didn’t experience a change in support, and whose depressive symptoms didn’t change. Cleary notes that in future work, it will be important to look at this group’s history in light of any caregiving they may have done for a spouse with a long-term illness.
The team also hopes that other researchers will study this same interaction of genetic risk, stress and social support in other populations.
In the meantime, Cleary and Sen say, the message for anyone going through stressful times, or watching a friend or relative go through stressful times, is to reach out and maintain or strengthen social connections.
Doing so can have benefits both for the person under stress, and the person reaching out to them, they note.
Reducing the level of ongoing stress that the person is facing, whether it’s at work, school, after a personal loss or in family situations can be critical.
And even though the study did not examine the role of professional mental health help, individual and group therapy is an important option for those who have developed depression or other mental health concerns.
Note: The polygenic risk score used in the study is validated for use on people of mainly European ancestry, which limits the ability to generalize the findings to people of other backgrounds. Sen notes that additional work is being done using data from the Intern Health Study and Health & Retirement Study to develop polygenic risk scores based on depression-related genetic traits in other populations including people of East Asian and African descent.