Research reportNeural systems underlying thought suppression in young women with, and at-risk, for depression

- Three groups of late-teens/young adult women; a group with depression, at risk for depression and healthy controls.
- Imaging paradigm used individual ruminative statements in a block/event related design.
- Activation of the DLPFC was greatest for HC > at-risk > MDD during thought suppression.
- Activation of the ACC was greatest for HC > at-risk > MDD during thought re-emergence.

ObjectiveRuminative brooding is associated with increased vulnerability to major depression. Individuals who regularly ruminate will often try to reduce the frequency of their negative thoughts by actively suppressing them. We aimed to identify the neural correlates underlying thought suppression in at-risk and depressed individuals.MethodsThree groups of women were studied; a major depressive disorder group, an at-risk group (having a first degree relative with depression) and controls. Participants performed a mixed block-event fMRI paradigm involving thought suppression, free thought and motor control periods. Participants identified the re-emergence of “to-be-suppressed” thoughts with a button press.ResultsDuring thought suppression the control group showed the greatest activation of the dorsolateral prefrontal cortex, followed by the at-risk, then depressed group. During the re-emergence of intrusive thoughts compared to successful re-suppression of those thoughts, the control group showed the greatest activation of the anterior cingulate cortices, followed by the at-risk, then depressed group.ConclusionsAt-risk participants displayed anomalies in the neural regulation of thought suppression resembling the dysregulation found in depressed individuals. The predictive value of these changes in the onset of depression remains to be determined.