Abstract:

Background: According to cognitive diathesis-stress theories, a latent cognitive vulnerability to depression is activated by negative affect in individuals at risk for depressive relapse. This vulnerability can manifest as mood-congruent memory during sad mood and may involve amygdala response, which is implicated in memory for emotionally arousing stimuli. This study examined whether amygdala modulates memory for negatively valenced words before and after a sad mood induction in healthy individuals with and without a history of recurrent major depression.

Methods: Fourteen unmedicated remitted depressed (RD) and 14 matched never depressed (ND) individuals were scanned using functional magnetic resonance imaging (fMRI) while performing a self-referent encoding/evaluation task (SRET) preceding and following a sad mood challenge. After each SRET, participants' free recall was assessed.

Results: Following sad mood induction, bilateral amygdala response during encoding of valenced words predicted increased recall of negative self-referent words for a subset of RD participants. This association was not present before the sad mood induction and was not evident in individuals without a history of depression, regardless of mood state.

Conclusions: These results are consistent with cognitive diathesis-stress theories and suggest a role for the amygdala in modulating mood-congruent memory during transient sad mood in individuals who are vulnerable to depression relapse.