Reaching out to encourage someone who is stressed is always a good idea. A new study reveals that support may be especially crucial for people whose genetic composition predisposes them to depression.
The study combines data from two very different groups of individuals under stress to highlight the role of social support in buffering the likelihood of developing depression symptoms in general, utilizing data from two very distinct groups of people under stress: new doctors in their most intense year of training and elderly persons whose spouses just died.
The greatest effect, however, was seen in those with the highest genetic variation that increased the risk of depression.
The study employs a polygenic risk score, which is based on decades of research into which minor differences in specific genes are associated to depression risk.
In comparison to those in the study who had low depression polygenic risk scores, doctors and widows with higher risk scores had greater rates of depression after losing social support, but also reduced rates of depression when they gained social support during stressful periods.
The study, published in the American Journal of Psychiatry by a University of Michigan team, suggests that more could be done to target social support to those who can most benefit.
Genes, stress and social connection
“Our data show wide variability in the level of social support individuals received during these stressful times, and how it changed over time,” said first author Jennifer Cleary, M.S., a psychology doctoral student at U-M who is doing her research with senior author Srijan Sen, M.D., Ph.D., of the U-M Medical School. “We hope these findings, which incorporate genetic risk scores as well as measures of social support and depressive symptoms, illuminate the 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 research reveals more of the DNA variation related to depression vulnerability, learning how that variation leads to depression is crucial.
“Further understanding the different genetic profiles associated with sensitivity to loss of social support, insufficient sleep, excessive work stress and other risk factors could help us develop personalized guidance for depression prevention,” he said. “In the meantime, these findings reaffirm how important social connections, social support and individual sensitivity to the social environment are as factors in wellbeing and preventing depression.”
Our data show wide variability in the level of social support individuals received during these stressful times, and how it changed over time. We hope these findings, which incorporate genetic risk scores as well as measures of social support and depressive symptoms, illuminate the gene-environment interactions and specifically the importance of social connection in depression risk.
Jennifer Cleary
Different populations, similar patterns
The new study made use of data from two long-term studies that collect genetic, mood, environment, and other information from communities of participants.
One is the Intern Health Study, which enrolls first-year medical residents (also called interns) around the United States and beyond, and which Sen directs.
The other is the Health and Retirement Study, based at the U-M Institute for Social Research and funded by the National Institute on Aging.
The new paper’s data came from 1,011 interns training at hospitals around the country, nearly half of whom were female, and from 435 recently widowed people, 71% of whom were women, who had data from surveys performed before and after their spouses died.
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.
Depressive symptoms increased 34% in widows and widowers compared to pre-widowhood levels. 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
The depression symptom data were then combined with each person’s polygenic risk score for depression, as well as their individual replies to questions about ties with friends, family, and other social supporters.
The majority of the interns lost social support from their pre-internship days, which aligns with the normal experience of leaving medical school and moving to a new workplace where they may not know anyone.
Interns with the greatest polygenic risk scores who also lost social support had the highest scores on depressive symptom measures later in the stressful intern year.
Those with the same high level of genetic risk who received social support, on the other hand, had much reduced depression 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 bereaved people reported an increase in social support following the death of their spouse, maybe because friends and family reached out to offer assistance or just a listening ear.
But the crossover effect was visible in them, too. Widows with a high hereditary risk for depression who received social assistance experienced a substantially lesser rise in depressive symptoms than their contemporaries with a similar genetic risk who did not receive social help after the death of a spouse.
Some widows lost social support or did not see a change in support, and their depressive symptoms did not improve. 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.
Individual and group therapy is an important alternative for persons who have developed depression or other mental health difficulties, even though the study did not investigate the role of professional mental health care.
Note: The polygenic risk score employed in the study has only been validated on persons of primarily European ancestry, limiting the capacity to extrapolate the findings to people of other origins.
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.
In addition to Cleary and Sen, the study’s authors are Yu Fang, M.S.E., Laura B. Zahodne, Ph.D., Amy S.B. Bohnert, Ph.D., and Margit Burmeister, Ph.D., all of U-M. Zahodne, Bohnert and Burmeister are members of the Eisenberg Family Depression Center; Sen and Burmeister are members of the Michigan Neuroscience Institute; Sen and Bohnert are members of the U-M Institute for Healthcare Policy and Innovation.
The National Institute of Mental Health (MH101459) and the National Institute of Child Health and Development (HD007109) funded the study.
