People with a history of depression respond differently than others to feeling guilty, brain scans show, a finding that may begin to explain how the emotions are processed by the brain.
Patients who had recovered from depression were more likely to show activation in areas of the brain associated with guilt, even when primed with scenarios where someone else was at fault, according to a study today in the Archives of General Psychiatry.
A century ago, Sigmund Freud proposed that excessive guilt was part of depression. Today’s study may point to how the brain experiences guilt and depression, said Roland Zahn, a study author and senior lecturer at the University of Manchester in the U.K. Though the study doesn’t say whether added sensitivity to guilt causes depression, the imaging may lead to new ways to diagnose vulnerability.
“It’s a very subtle change,” Zahn said. “These people are more prone to overgeneralize guilt, to feel guilty for everything. But something else must trigger depression, because when we saw them, they were quite well. Something must interact with this.”
Perhaps, if these people were to lose their jobs or be dumped by a romantic partner, they would be more likely to blame themselves, and less likely to take into account extenuating circumstances, Zahn said.
“These people may lose hope and think, ‘Maybe I’m a total failure, I can’t do anything right,’” Zahn said.
The researchers recruited 22 healthy people with no family history of depression and 25 people who had previously had a major depressive episode. They were then asked to imagine they had behaved poorly toward their best friend, or that their best friend had acted badly toward them. The people who had previously been depressed were less able to coordinate brain regions to become indignant when they were wronged.
Because of the past depression, it’s not clear whether the abnormal activation was a “scar” from depression, or the vulnerability itself, said Helen Mayberg, a neurologist at Emory University in Atlanta, who wasn’t involved in the research. The areas implicated are the same ones she’s targeted in her treatment of depression with deep brain stimulation, she said.
“Depressed people do get into this spin cycle, and I think the concept is really fantastic, because it’s not enough to just feel bad,” Mayberg said. “You don’t blame yourself when you have cancer. But here, the areas of your brain that don’t work right cause you to blame yourself.”
People who have previously been depressed are more likely to experience another depressive episode, Zahn said. Knowing how the brain is vulnerable may help researchers target treatments, whether through therapy or new kinds of medication.
The next step is to see if imaging can predict whether someone will have another episode of depression within the year, Zahn said. He and his colleagues are also considering ways of seeing if the unusual activation of the anterior temporal lobe, the area affected, can be unlearned, he said.
Mayberg also suggested recruiting people with family histories of depression who haven’t yet gotten sick to see if they show similar patterns.
Today’s study was funded by the University of Manchester and the Wellcome Trust, among others.