Stress-induced alterations in neural responsivity to monetary reward cues in unmedicated individuals with variable appetite/weight phenotypes of Major Depressive Disorder

Background: People with major depressive disorder (MDD) often experience changes in appetite during depressive episodes. People who tend to experience increased appetite (“HYPERphagia”) exhibit different clinical outcomes than those who have decreased appetite (“HYPOphagia”). Since food is characterized as a reward, these differences in appetite changes we see in MDD may be the result of stress-induced alterations in the reward centers of the brain, but there is little research in this area. This study examined the impact of stress on reward-related brain regions of people with HYPER or HYPO MDD (compared to healthy controls [“HC”]) by looking at brain reactivity to monetary cues.

Methods: Forty HC, 29 HYPO, and 21 HYPER (all unmedicated) completed two study visits: one including a stress (S) test and the other a no-stress (NS) version of the same test. Both visits included blood draws to measure cortisol and an fMRI scan where participants completed a money-related (“Monetary Incentive Delay” or MID) task.

Results: HYPER and HYPO individuals exhibited stress-induced altered activity in the reward centers of the brain, specifically, in the hypothalamus and right pallidum.

Conclusion: Diverging appetite-related changes in MDD are marked by distinct stress-related brain activation patterns, highlighting areas for developing targeted treatments for MDD.