Overview: Social support during stressful times helps reduce the risk that people with a genetic predisposition to depression will develop symptoms.
Source: University of Michigan
It’s always a good idea to reach out to someone who is under stress. But a new study suggests that support may be especially important for someone whose genetic makeup makes them more likely to develop depression.
The study demonstrates the importance of social support in buffering the risk of developing depression symptoms in general, using data from two very different groups of people under stress: new doctors in the most intense year of training and older adults of whom the spouses have recently passed away.
But the greatest effect was seen in those with the most genetic variation who increased the risk of depression.
The paper uses a measure of genetic risk called a polygenic risk score, which is based on decades of research into the small variations in specific genes associated with depression risk.
Compared to individuals in the study who had low polygenic risk scores for depression, the doctors and widows with higher risk scores had more depression after they lost social support, but also had less depression when they received social support during stressful times.
The study, published in the American Journal of Psychiatry by a team from the University of Michigan suggests that more could be done to target social support to those who would benefit most.
Genes, stress and social connection
“Our data show a wide variability in the level of social support individuals received during these stressful times, and how this changed over time,” said first author Jennifer Cleary, MS, a U-M psychology doctoral student who conducts research with senior author Srijan Sen, MD, Ph.D., of UM Medical School.
“We hope that these findings, which include genetic risk scores as well as measures of social support and depressive symptoms, elucidate gene-environment interactions and specifically the importance of social connection in depression risk.”
Sen, who is the director of the Eisenberg Family Depression Center and a professor of psychiatry and neuroscience, adds that even as genetic testing reveals more of the DNA variation associated with vulnerability to depression, it is crucial to learn how that variation leads to depression.
“A better understanding of the different genetic profiles associated with susceptibility to loss of social support, inadequate sleep, excessive work stress and other risk factors could help us develop personalized guidelines for depression prevention,” he said.
“Meanwhile, these findings reaffirm the importance of social connections, social support, and individual sensitivity to the social environment as factors in well-being and prevention of depression.”
Different populations, similar patterns
The new study used data from two long-term studies that both capture genetic, mood, environmental and other data from populations of participating individuals.
One is the Intern Health Study, which enrolls first-year medical residents (also called interns) in the United States and abroad and which Sen directs.
The other is the Health and Retirement Study, based at the UM Institute for Social Research.
The data for the new paper came from 1,011 interns training in hospitals across the country, nearly half of whom were women, and 435 recently widowed, 71% of whom were women, who had data from surveys conducted before and after the death of their husbands. .
As Sen and his team have shown in previous work, depressive symptoms in the trainees increased dramatically (126%) during the stressful year of training with long and irregular work hours – often in environments far from friends and family.
In the widows and widowers, depressive symptoms increased by 34% compared to their pre-widowhood scores. This is consistent with previous research showing that the loss of a partner can be one of the biggest stressors in a person’s life, Cleary said.
A crossover effect
Next, the researchers paired 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 interns lost social support during their pre-internship days — which fits well with the general experience of leaving the place where they went to medical school and moving to a new environment where they may not know anyone.
Interns who had the highest polygenic risk scores and also lost social support scored the highest scores on measures of depression symptoms later in the stressful internship year.
However, those with the same high genetic risk who received social support had far fewer depressive symptoms. It was even lower than their low genetic risk peers, regardless of what happened to their social support. The researchers call this a ‘crossover effect’.
In contrast to the interns, some widowers reported an increase in social support after the loss of their partner, possibly because friends and family reached out to offer help or simply to lend a listening ear.
But the crossover effect was also visible there. Widows with a high genetic risk for depression who received social support showed a much smaller increase in depressive symptoms than their peers with a similar genetic risk who lost social support after losing a partner.
There were also some widows who lost social support or experienced no change in support, and whose depressive symptoms did not change. Cleary notes that in future work it will be important to look at the history of this group in light of any care they may have provided to a partner with a long-term illness.
The team also hopes that other researchers will study the 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 seeing a friend or family member going through stressful times, is to reach out and maintain or strengthen social connections.
This can have benefits for both the person under stress and the person contacting them, they note.
Reducing the level of ongoing stress the person faces, whether at work, school, after a personal loss, or in family situations, can be critical.
And while the study didn’t examine the role of mental health professionals, individual and group therapy is an important option for those who have developed depression or other mental health problems.
About this news about genetics and depression research
Writer: Press Office
Source: University of Michigan
Contact: Press Service – University of Michigan
Image: The image is in the public domain
Original research: Closed access.
“Polygenic risk and social support in predicting depression under stress” by Jennifer L. Cleary et al. American Journal of Psychiatry
Polygenic risk and social support in predicting depression under stress
Despite substantial progress in identifying genomic variation associated with major depression, the mechanisms by which genomic and environmental factors together influence the risk of depression remain unclear. Genomically transmitted sensitivity to the social environment may be a mechanism linking genomic variation and depressive symptoms. The authors assessed whether social support affects the likelihood of developing depression differently across the spectrum of genomic risk in two samples that experienced substantial life stress: 1,011 first-year training physicians (trainees) in the Internal Health Study (IHS) and 435 recently widowed Health and Retirement Study (HRS) participants.
Participants’ depressive symptoms and social support were assessed with questionnaires administered before and after the life stressor. Polygenic risk scores (PRSs) for major depressive disorder were calculated for both samples.
Depressive symptom scores increased by 126% after the start of the internship in the IHS sample and by 34% after widowhood in the HRS sample. There was an interaction between depression PRS and change in social support in the prediction of depressive symptoms in both the IHS sample (incidence ratio [IRR]=0.96, 95% CI=0.93, 0.98) and the HRS sample (IRR=0.78, 95% CI=0.66, 0.92), associated with higher depression PRS with greater sensitivity to changes in social support. Johnson-Neyman intervals indicated a crossover effect, where loss and gain in social support moderated the effect of PRS on depressive symptoms. (Johnson-Neyman interval in the IHS sample, −0.02, 0.71; in the HRS sample, −0.49, 1.92).
The study’s findings suggest that individuals at high genomic risk of developing increased depressive symptoms under adverse social conditions also benefit more from nurturing social environments.