In 1978, Dr. Constance Hammen received a new book in the mail to review, written by a pair of sociologists named George W. Brown and Tirril Harris. It was “Social Origins of Depression.”
“I thought, wow, that’s great,” said Hammen, who was then beginning to build a career at the forefront of research into mood disorders. “What a tool. And how great that sociologists came up with a concept for the context in which stress and depression occurs.”
The book investigated clinical depression “as an understandable response to adversity” and helped prod Hammen to examine the role of acute and chronic stress throughout one’s life and across generations. “We could imagine practically anyone developing depression given a certain set of environmental circumstances,” the authors wrote.
And yet, the subtitle of the book revealed the field’s focus on depression: “A Study of Psychiatric Disorder in Women” because depression was considered a disease of middle-aged women. “To a great majority of the medical community, it was as though men and younger people just weren’t depressed,” Hammen said.
But research on depression has come a long way since 1978, a topic that Hammen discussed with an engaged audience at a Grand Rounds presentation in May sponsored by the Women’s Behavioral Health Division of Yale School of Medicine’s Department of Psychiatry.
“We recognize now that depression is both a serious disorder and it is widespread,” said Hammen, a Distinguished Professor of Psychology and Psychiatry and Biobehavioral Sciences at the University of California, Los Angeles. “And it affects large numbers of the population across all cultures, across all nations. And particularly women.”
In fact, depression is the leading cause of disability for women worldwide. About 8 percent of Americans 12 and over have some form of current depression, though rates are higher in women and people between the ages of 18 and 29. People living below the poverty line suffer depression at rates 2.5 times greater than those more economically secure.
Experts in 2010 estimated that the annual economic cost of depression in the United States amounts to $210 billion, a number that’s likely far greater today.
Before publication of the third edition of the American Psychological Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM-III) in 1980, mental health professionals had no codified criteria for diagnosing depression in patients. There was little understanding of its causes, and there were no effective treatments.
Published in 2013, the DSM-V defines major depressive disorder (MDD) as occurring in someone who experiences a “depressed mood or a loss of interest or pleasure in daily activities for more than two weeks” as well as five or more other symptoms that could include loss of sleep or substantial weight loss.
Most importantly, Hammen explained, although researchers and clinicians now understand that emotional, cognitive, biological, and behavioral factors play a role in the development of depression, stress can act to provoke underlying vulnerabilities within this spectrum of factors.
“Stress is a concept that emerges as a core construct in depression, a core player,” she said. “I think questions of how this stress gets ‘under the skin’ are vitally important and very interesting. But I’ve always been more interested in what goes on in people’s lives and in the environment.”
Dr. Carolyn M. Mazure recalled how the start of her own research into stress as a trigger for depression was met with skepticism about the ability to effectively measure stress and prove its link to a physical disease state.
“Yet when I saw patients, it was apparent that there was a strong interaction among biological factors, mental and emotional health, and factors in the environment — especially stress,” Mazure said.
It’s an exciting ride to be able to discover something new.
Dr. Constance Hammen
Hammen noted in her presentation that stress can trigger depression but clearly not always. People most at risk for stress precipitating depression include females, those who have a depressed parent, and those who experience interpersonal difficulties.
While it is important to understand the effects of acute, negative life events, Hammen and her colleagues examined the ramifications of chronic stress and how it negatively affects daily functioning. For example, people who suffered from chronic maltreatment as children show a higher likelihood of developing depression as adolescents and adults.
Hammen and her colleagues also have shown that children who were depressed by age 15 had less satisfying romantic relationships by the time they turned 20. And in another study, she learned that youth are more susceptible to high interpersonal stress, particularly what she called “targeted rejected events” such as a non-mutual breakup or getting fired from a job.
Although depression runs in families, “children inherit not just the genetic predispositions, but the constellation of adverse circumstances producing stress that can lead to depression,” Hammen said.
The quality of parenting becomes an essential ingredient in contributing to whether depression is likely to occur in the next generation. Hammen stressed the urgent need to identify children at risk early on, particularly teenagers at the highest levels of risk.
“Environmental stress sculpts the brain in childhood, affecting neurobiological mechanisms associated with stress reactions,” she said, echoing work advanced by Dr. Hilary Blumberg, the John and Hope Furth Professor of Psychiatric Neuroscience and Professor of Psychiatry at Yale.
In addition to medication and other therapies, mental health practitioners must help patients learn to confront stress in more adaptive ways by considering the totality of the environment that causes stress, Hammen said.
“When you’re treating a depressed adult, there is a family to consider, whether that is a traditional family or essential individuals who make up a family constellation,” she said.
But even after learning so much over so many years, Hammen still embraces trying new techniques for measuring stress and evaluating its effect on depression.
“It’s an exciting ride to be able to discover something new that sheds light on a subject as important as this,” she said.
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