Abstract
Objective: The authors examined whether alterations in the brain’s reward network operate as a mechanism across the spectrum of risk for depression. Second, they tested whether these alterations are specific to anhedonia as compared to low mood, and predictive of depressive outcomes.
Method: Functional MRI was used to collect BOLD responses to anticipation of reward in the Monetary Incentive Task from 1,576 adolescents of a community-based sample. Adolescents with current and future subthreshold depression and clinical depression were compared to healthy controls in matched comparisons. 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 subthreshold- and clinical-depression compared to healthy controls. Low ventral striatum activation predicted transition to subthreshold or clinical depression in previously healthy adolescents at two-year follow up. Brain responses during reward anticipation decreased in a graded manner between healthy adolescents, adolescents with current or future subthreshold depression and those 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 ventral striatum in all analyses.
Conclusions: Reduced striatal activation operates as a mechanism across the risk spectrum for depression. It is associated with anhedonia in healthy adolescents, a behavioural indicator of positive valence systems, consistent with predictions based on the RDoC.
Method: Functional MRI was used to collect BOLD responses to anticipation of reward in the Monetary Incentive Task from 1,576 adolescents of a community-based sample. Adolescents with current and future subthreshold depression and clinical depression were compared to healthy controls in matched comparisons. 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 subthreshold- and clinical-depression compared to healthy controls. Low ventral striatum activation predicted transition to subthreshold or clinical depression in previously healthy adolescents at two-year follow up. Brain responses during reward anticipation decreased in a graded manner between healthy adolescents, adolescents with current or future subthreshold depression and those 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 ventral striatum in all analyses.
Conclusions: Reduced striatal activation operates as a mechanism across the risk spectrum for depression. It is associated with anhedonia in healthy adolescents, a behavioural indicator of positive valence systems, consistent with predictions based on the RDoC.
| Original language | English |
|---|---|
| Pages (from-to) | 1215-1223 |
| Journal | The American Journal of Psychiatry |
| Volume | 172 |
| Issue number | 12 |
| Early online date | 18 Jul 2015 |
| DOIs | |
| Publication status | Published - 1 Dec 2015 |