In the never-depressed people, there was a synchrony in the firing of two brain regions, one involving socially appropriate behavior (the anterior temporal lobe) and the other involving feelings of guilt (the subgenual cingulate cortex and nearby septal region, or SCSR). These two regions fired together whether the person was experiencing guilt or indignation. But the brains of formerly-depressed people had a kink: The two regions fired together when experiencing indignation, but during guilt, the activation of the two regions was “uncoupled” so that they did not communicate with each other. People who had higher levels of self-blame also had more “decoupling” of the two brain regions, which suggests a strong connection between what’s going on in the brain and the specific behavior.

“The scans revealed that the people with a history of depression did not ‘couple’ the brain regions associated with guilt and knowledge of appropriate behaviour together as strongly as the never depressed control group do,” said author Roland Zahn. “Interestingly, this ‘decoupling’ only occurs when people prone to depression feel guilty or blame themselves, but not when they feel angry or blame others. This could reflect a lack of access to details about what exactly was inappropriate about their behaviour when feeling guilty, thereby extending guilt to things they are not responsible for and feeling guilty for everything.”