The Brain’s Response to Reward Anticipation and Depression in Adolescence: Dimensionality, Specificity, and Longitudinal Predictions in a Community-Based Sample.
AJP. 2015-12-01; 172(12): 1215-1223
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OBJECTIVE: The authors examined whether alterations in the brain’s reward network
operate as a mechanism across the spectrum of risk for depression. They then
tested whether these alterations are specific to anhedonia as compared with low
mood and whether they are predictive of depressive outcomes.
METHOD: Functional MRI was used to collect blood-oxygen-level-dependent (BOLD)
responses to anticipation of reward in the monetary incentive task in 1,576
adolescents in a community-based sample. Adolescents with current subthreshold
depression and clinical depression were compared with matched healthy subjects.
In addition, BOLD responses were compared across adolescents with anhedonia, low
mood, or both symptoms, cross-sectionally and longitudinally.
RESULTS: Activity in the ventral striatum was reduced in participants with
subthreshold and clinical depression relative to healthy comparison subjects. Low
ventral striatum activation predicted transition to subthreshold or clinical
depression in previously healthy adolescents at 2-year follow-up. Brain responses
during reward anticipation decreased in a graded manner between healthy
adolescents, adolescents with current or future subthreshold depression, and
adolescents with current or future clinical depression. Low ventral striatum
activity was associated with anhedonia but not low mood; however, the combined
presence of both symptoms showed the strongest reductions in the ventral striatum
in all analyses.
CONCLUSIONS: The findings suggest that reduced striatal activation operates as a
mechanism across the risk spectrum for depression. It is associated with
anhedonia in healthy adolescents and is a behavioral indicator of positive
valence systems, consistent with predictions based on the Research Domain