Neuroanatomical Prediction of Anhedonia in Adolescents.

Anhedonia is a transdiagnostic risk factor implicated in mental illness onset, treatment non-response, and suicidal behaviors. Prior cross-sectional research in adults has shown that anhedonia is associated with reduced dorsal striatal volume, but it is unknown whether this relationship extends to adolescents and whether reduced striatal volume prospectively predicts anhedonia. To address these gaps, the current study investigated whether striatal volume predicted anhedonia severity in adolescents. At baseline, healthy female adolescents aged 12-14 years (n=50) completed a clinical assessment, and structural MRI data were acquired on a 3 Tesla MR scanner. While in the scanner, participants also completed a peer feedback task where subjective ratings following peer 'acceptance' or 'rejection' were obtained. At the three-month follow-up, participants provided self-report assessments of anhedonia, depression, and anxiety symptoms. Three main findings emerged. First, in cross-sectional analyses, right nucleus accumbens volume was inversely related to anhedonia severity. Second, reduced bilateral putamen volume prospectively predicted anhedonia severity while controlling for baseline anhedonia, depression, and anxiety symptoms. Third, a blunted subjective response to peer acceptance (ie, neutral response to positive feedback), but not a more negative subjective response to peer rejection, contributed to anhedonia severity, but only among youth with smaller putamen volume. Collectively, these results suggest that smaller volume in striatal regions critically implicated in reward processing is associated with current and future anhedonic symptoms among healthy female youth. These anatomical features may confer vulnerability to anhedonia and thus, may inform early identification of individuals at high risk for mental illness.