Divergent Neural Correlates of Clinician-Rated and Self-Reported Depressive Symptoms in Parkinson’s Disease

Depressive symptoms in Parkinson's disease reflect large-scale brain network dysfunction. Clinician-rated instruments such as the seventeen-item Hamilton Depression Rating Scale and patient-reported measures such as the Beck Depression Inventory second edition target distinct somatic versus cognitive-affective symptom profiles. This retrospective study investigated the resting-state functional magnetic resonance imaging correlates underlying these divergent clinical assessments. We examined thirty-eight patients with Parkinson's disease during the clinically confirmed medicated state using a hypothesis-driven seed-based region-of-interest approach. Evaluated regions included the posterior cingulate cortex, medial prefrontal cortex, anterior cingulate cortex, left amygdala, left middle frontal gyrus, and left caudate. Multiple linear regression models adjusting for age, sex, Hoehn and Yahr stage, and daily pramipexole dosage revealed that functional connectivity between the posterior cingulate cortex—a core hub of the default mode network—and the left amygdala exhibited a strong positive association with clinician-rated depression severity. In contrast, no significant functional connectivity alterations correlated with self-reported depression scores. Furthermore, attenuated left caudate–left amygdala and medial prefrontal cortex–anterior cingulate cortex connectivity was associated with advanced age, whereas enhanced medial prefrontal cortex–left amygdala connectivity was linked to higher daily pramipexole intake. These findings demonstrate that somatically weighted clinician ratings uniquely correspond to hyperconnectivity between the default mode network and limbic structures. Differentiating somatic from cognitive-affective dimensions is essential for accurate clinical evaluation, neuroimaging biomarker discovery, and targeted pharmacological management in Parkinson's disease depression.