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Reward positivity tied to symptom improvement after depression treatment

An increase in reward positivity correlated with a drop in depressive and anxiety symptoms after treatment with cognitive behavioral therapy and selective serotonin reuptake inhibitors in patients with depression, according to study findings.

“Studies have found evidence for a blunted [reward positivity] among adults in remission from depression,” Katie L. Burkhouse, PhD, of the department of psychiatry, University of Illinois-Chicago, and colleagues wrote in the Journal of Clinical Psychiatry. “No studies to date, however, have examined the malleability, or lack thereof, of the [reward positivity] in these populations as it pertains to treatment. Specifically, it remains unknown whether the [reward positivity] can be altered as psychiatric symptoms change over time and is therefore a candidate treatment target.”

The investigators examined differences in reward positivity in patients before and after 12 weeks of treatment with SSRI or CBT, as well as the utility of reward positivity as a predictor of symptom change during both these treatments.

At baseline and 12 weeks, 63 adults with a primary anxiety or depressive disorder and 25 healthy controls completed a monetary award task while the researchers recorded electroencephalogram (EEG). Participants completed CBT or SSRI treatment between EEG sessions, where they wore an EEG cap while undergoing a computer task that asked them to choose one of two doors, according to a press release. If they chose the correct door, the participant would win a small amount of money, but if they chose the wrong door, they would lose money.

The results demonstrated that increased depressive symptoms were linked to a more attenuated reward positivity at baseline. Although there were no significant differences between patients and healthy controls in the degree of reward positivity change during the 12 weeks of treatment, the extent of increase in the reward positivity correlated with the extent of decline in depressive (P = .03) and anxiety (P = .02) symptoms within patients after CBT and SSRI treatment. Lesser reward positivity at baseline predicted a greater deduction in depressive symptoms following SSRIs (P < .05), but not following CBT.

“These findings highlight neural responsiveness to reward as both a mechanism and predictor of depressive symptom change that may be used to not only serve as an objective index of symptom improvement but also to help guide treatment selection,” Burkhouse and colleagues wrote. “Future mechanistically-based interventions aimed at directly enhancing the reward positivity may prove to be most useful in reducing depression symptoms for patients who demonstrate preexisting deficits in this area.” – by Savannah Demko

Disclosure: The authors report no relevant financial disclosures.