Two studies explore some of the developmental roots of depression in childhood and adolescence.
In the first study, published in the journal Clinical Psychological Science, researchers focused on depressive rumination, or the relentless focus on what has gone wrong or will go wrong, coupled with an inability to see a solution to these overwhelming problems. It’s no surprise that rumination has a strong connection to depression— in fact, studies show that some talk therapies can actually make depression worse by compelling people to focus on problems and their origins, rather than guiding them toward positive solutions on what to do about them.
To better understand what role rumination might play in seeding depression to begin with, however, the researchers, led by Mollie Moore at the University of Wisconsin-Madison studied 756 young adolescent twins, aged 12 to 14. They compared identical twins, who share the same genes, to fraternal twins, who are no more genetically alike than other siblings, using questionnaires designed to tease out whether the teens tended to brood over their problems and their insolubility or whether they thoughtfully reflected on them with an eye toward finding possible solutions. What psychologists have labeled “moody pondering” or brooding is more likely to be associated with depression, while reflection may actually be helpful as a coping mechanism for emotional or challenging experiences. The authors also looked at whether the teens were able to distract themselves from their problems, noting that “individuals who have a greater tendency to ruminate and a lesser tendency to distract are at the greatest risk for experiencing depressive symptoms.”
They found that while much of brooding is influenced by environmental influences such as parenting and peers, virtually all of the connection between whether that brooding is associated with depression may be driven by genes. Someone who inherits a tendency to brood, in other words, also seems to inherit a tendency to become depressed.
“I appreciated the authors’ distinction between brooding and distraction and their finding that the two played opposite roles,” says Gregory Smith, professor of psychology at the University of Kentucky in Lexington, who was not associated with the research, “At the core, they found that although brooding is not highly heritable, genetic influences appear to contribute to the relationship between brooding and depression.”
That doesn’t mean that people who brood are necessarily at higher risk of depression. Because the research only looked at the twins at one point in time, the authors note that “it remains unclear from our results alone whether brooding is a risk factor for depression or is merely associated with depressed mood concurrently.” Since rumination can be re-directed and managed through cognitive behavioral therapy or other interventions, figuring out whether the tendency to brood can trigger depression could lead to early and effective treatments, which might actually prevent depression by stopping ruminating before it becomes engrained in brain circuitry.
Smith, who is also investigating some of the potential root causes of depression, reports in his study, published in Psychological Science, on an interesting connection between depression and people’s tendency to act without thinking when faced with strong emotion, known among psychologists as “urgency.” Although this behavior seems unrelated to depression, he and his colleagues found a surprising link.
“In numerous longitudinal studies, [urgency] has been shown to predict subsequent involvement in a range of rash, ill-advised behaviors, including problem drinking, pathological gambling, smoking, risky sex, drug use, binge eating, and others,” he says.
And what’s driving these behaviors is an impulse to act without considering the consequences. “It might be [more] useful to understand impulsivity more broadly: as the tendency to respond to an immediate urge or need, without due consideration of one’s ongoing, long-term interests and health,” Smith says.
That can lead to not acting when it’s necessary, as well as actively making poor choices. “Sometimes inaction can meet an immediate need at the expense of an ongoing goal pursuit,” he says. “For example, one might be very nervous about asking one’s boss for a promotion and raise. Inaction [not asking] would alleviate the immediate nervousness, but at the expense of one’s longer-term interests.”
In the study, Smith and his colleagues studied over 1,900 fifth graders as they made the transition from elementary school into sixth grade middle school. After controlling for factors like gender and early onset of puberty that could also affect depression, they found that fifth grade urgency was one of the best predictors of being depressed in sixth grade: the only greater predictor was already having been depressed in fifth grade.
And this prediction held up even after the authors controlled for early involvement with smoking, drinking or binge eating: addictive behaviors that might themselves lead to depression because of their negative consequences. Instead, the findings suggest that impulsivity in the face of emotion — leading to either action or inaction — increases risk for both addictive disorders and depression.
While the connections between either ruminative negative thoughts or impulsive behaviors and depression might seem obvious, such finer-grained understanding of how these tendencies may contribute to depression could lead to better ways of preventing an array of behavior problems.