Early Adversity, Adult Misery: How Small Events Trigger Depression

A new study confirms that childhood wounds don't always heal--and explains why some challenges reopen them and others don't

The brain does something weird when confronted with stress: It kills off neurons that could help it defend itself, and prevents new brain cells from forming in the hippocampus, a region associated with healthful stress responses. For years, mental health experts have tracked how this biological chain of events plays out in real life. Numerous studies on victims of childhood abuse, loss, or parental separation have documented how such woes make them more vulnerable to stress and, consequently, depression in a process called stress sensitization. They tend to go through more depressive episodes and get depressed following relatively minor problems. They're wounded indefinitely.

But the small stressors that trigger depressive episodes in this at-risk population haven't been studied much: that topic, says Kimberly Dienes, a Roosevelt University psychologist, "is relatively unexplored territory." To learn more about how little obstacles can lead to full-blown depression, George Slavich of the University of California, Los Angeles, worked with University of Notre Dame's Scott Monroe and Stanford University's Ian Gotlib for a study to be published in the Journal of Psychiatric Research.

The team conducted in-depth interviews with 100 adults who had gone through episodes of major depressive disorder but had been asymptomatic for at least six months. Among the 49 participants who reported a history of parental loss during childhood, 23 had divorced or separated parents, eight had a deceased parent, five were abandoned, six had parents who were absent due to work, and seven had absentee parents for other reasons. The researchers inquired about each person's experiences with depression, and the severity and nature of the stressors involved.

Much like other researchers, Slavich and his collaborators observed that individuals who went through childhood trauma were more likely to get depressed when they encountered less serious ordeals as adults. They noticed a new twist, however: This effect was unique to respondents whose depressive episodes were prompted by interpersonal stress, such as the demise of a budding romance or the transfer of an office confidant. "Everyone in the study developed depression," Slavich adds, "but those who do not have a history of early parental loss were, on average, more resilient."

That small setbacks spark depression doesn't surprise UCLA researcher Steve Cole, whose own research has linked early-life difficulty with adult immune-system deficiencies. "The most toxic life stress involves social stress," he says, adding that what he found interesting is how Slavich's work on selective stress sensitization seems to reaffirm the work of psychoanalysts like Sigmund Freud. "Of course their detailed theories are not likely to be true," he says, "but this suggests they were right in that deeper historical patterns play a major precipitating role."

Queen's University psychology professor Kate Harkness says the Freudian "matching" of the nature of early and later stress is indeed intriguing and warrants future investigation. "It shows that early loss events sensitize individuals specifically and preferentially in the same loss domain," she says. Slavich agrees but has reservations: "The matching hypothesis is very interesting. But it's also possible that more severe types of early adversity like abuse may sensitize people to all forms of later life stress."

Still, the study's recognition of the power of seemingly trivial interpersonal loss is enough to advance depression interventions. Cole suggests that, since childhood heartbreak plays a major role in a patient's resilience to stress, psychologists should review more than a patient's immediate past when taking a patient history. They must be cautious when patients share stressful interpersonal loss events, adds Williams College psychology professor Catherine Stroud, no matter how inconsequential they seem. More specifically, Dienes says the finding bolsters the use of cognitive behavioral therapy (CBT), which is typically used to correct misguided and maladaptive beliefs, in depression treatment and prevention. "Cognitive distortions may arise from early feelings of abandonment," she says. "This research gives therapists a target to focus on for individuals at-risk for depression."

Harkness says a nontraditional alternative is also available for those who may prefer to combat depression on their own: mindfulness meditation. As the authors of The Mindful Way Through Depression explain on their site:

When you enter a phase in your life during which you are vulnerable to depression, you lose touch with what is going on around you. It is a sort of tunnel vision; you can only see part of the landscape... Low mood can bring back memories and thoughts from the past, and make you worry about the future. Mindfulness helps to halt the escalation of these negative thoughts and teaches you to focus on the present moment, rather than reliving the past or pre-living the future.

Regardless of how people deal with the remnants of their fractured childhoods, though, Harkness emphasizes the need for vigilance. "Early experiences stay with us," she says. "They make strong and distinct impressions in our minds and brains."

Image: apdk/flickr