Recalling happy memories in remitted depression: a neuroimaging investigation of the repair of sad mood.

Major depressive disorder (MDD) is a recurrent mood disorder. The high rate of recurrence of MDD suggests the presence of stable vulnerability factors that place individuals with a history of major depression at an increased risk for the onset of another episode. Previous research has linked the remitted state, and therefore increased vulnerability for depressive relapse, with difficulties in the use of pleasant autobiographical memories to repair sad mood. In the present study, we examined the neural correlates of these difficulties. Groups of 16 currently euthymic, remitted depressed individuals and 16 healthy (control) women underwent functional magnetic resonance imaging (fMRI) during sad mood induction and during recovery from a sad mood state through recall of mood-incongruent positive autobiographical memories. Sad mood was induced in participants by using film clips; participants then recalled positive autobiographical memories, a procedure previously shown to repair negative affect. During both the sad mood induction and automatic mood regulation, control participants exhibited activation in the left ventrolateral prefrontal cortex (vlPFC) and cuneus; in contrast, remitted participants exhibited a decrease in activation in these regions. Furthermore, exploratory analyses revealed that reduced activation levels during mood regulation predicted a worsening of depressive symptoms at a 20-month follow-up assessment. These findings highlight a dynamic role of the vlPFC and cuneus in the experience and modulation of emotional states and suggest that functional anomalies of these brain regions are associated with a history of, and vulnerability to, depression.