Reward-related decision-making in pediatric major depressive disorder: an fMRI study

Abstract

Background: Although reward processing is considered an important part of affective functioning, few studies have investigated reward-related decisions or responses in young people with affective disorders. Depression is postulated to involve decreased activity in reward-related affective systems.

Methods: Using functional magnetic resonance imaging (fMRI), we examined behavioral and neural responses to reward in young people with depressive disorders using a reward decision-making task. The task involved choices about possible rewards involving varying magnitude and probability of reward. The study design allowed the separation of decision/anticipation and outcome phases of reward processing. Participants were 9-17 years old and had diagnoses of major depressive disorder (MDD), anxiety disorders, or no history of psychiatric disorder.

Results: Participants with MDD exhibited less neural response than control participants in reward-related brain areas during both phases of the task. Group differences did not appear to be a function of anxiety. Depressive and anxiety symptoms were associated with activation in reward-related brain areas.

Conclusions: Results suggest that depression involves altered reward processing and underscore the need for further investigation of relations among development, affective disorders, and reward processing.

Figures

Figure 1

Design of the reward task. The upper left panel depicts decision the stimuli, showing each of the four possible trial types. The upper right panel depicts outcome stimuli. The lower panel depicts trial timing. The complete trial consisted of a decision phase and an outcome phase, each lasting 12 s. Imaging data were acquired at 6 time points during each phase.

Figure 2

Images showing significant main effects or interactions with group (p<.05, in red) in (a) anticipation/decision and (b) outcome phases. Blue regions were examined but not significant.