Mood-induced changes on the Implicit Association Test in recovered depressed patients.

A mood induction paradigm was used to examine dysphoria-related changes in two types of cognitive processing in individuals who had previously experienced depression. Formerly depressed patients (n = 23) and never-depressed controls (n = 27) completed the Dysfunctional Attitudes Scale, a self-report measure of effortful processing, and performed the Implicit Association Test, an automatic-reaction time task that measures evaluative bias, before and after a negative-mood induction. The formerly depressed group showed both an increase in endorsement of dysfunctional attitudes and a more negative evaluative bias for self-relevant information after the induction, relative to controls--however, there was no association between the mood-linked changes observed on these two measures. The shift in evaluative bias shown by the formerly depressed group was similar to that seen in a group of 32 currently depressed individuals. These findings suggest that even a mild negative mood in formerly depressed individuals can reinstate some of the cognitive features observed in depression itself.

Effects of self-generated sad mood on regional cerebral activity: a PET study in normal subjects.

This study investigated the cerebral regions modulated by self-generated sad mood in normal subjects. Eleven healthy men experienced a temporary sad mood by recalling sad personal memories. Two control states were used for comparison: a resting condition, and a condition involving the recall of affectively neutral personal events. Regional cerebral blood flow (rCBF) images were obtained using [15O]-H2O Positron Emission Tomography. A statistical comparison of the images during negative mood and neutral recall conditions revealed that sad mood was associated with a decrease in rCBF in the left dorsolateral prefrontal, left medial prefrontal, and left temporal cortex; no increase in activity was noted in this comparison. Our results are consistent with the noted left prefrontal decrease in metabolism found in depressed patients through a variety of methodologies; however, our results contrast with findings of increased left or bilateral prefrontal activity in transient induced negative mood states reported for women (George et al., 1995, Am J Psychiatry 152:341-341) and for mixed-gender (Pardo et al., 1993, Am J Psychiatry 150:713-719) subject groups. The study brings to light a number of methodological issues, including the crucial importance of the baseline condition used for the isolation of the emotional components of a given task.