Differences in correlations of depression and anhedonia with cardiovascular sympathetic functions during a head-up tilt test in drug-naïve Parkinson’s disease patients

Background Depression is a symptom of Parkinson’s disease (PD) and may be correlated with cardiovascular sympathetic function. Anhedonia is an element of depression, but these symptoms can emerge independently in PD. A correlation of anhedonia with cardiovascular sympathetic function has rarely been examined. Objective To compare correlations of depression and anhedonia with cardiovascular sympathetic function in drug-naive PD patients. Methods Assessments of depression (Self-rating Depression Scale; SDS), anhedonia (Snaith–Hamilton Pleasure Scale; SHAPS), myocardial 123 I-MIBG ( 123 I-meta-iodobenzylguanidine) scintigraphy (heart to mediastinum (H/M) ratios in early and delayed images), and head-up tilt test (HUT) up to 60° for 10 min were performed in 45 drug-naïve PD patients. During the HUT, blood pressure was measured every minute and the maximum decrease in systolic blood pressure (SBP) was determined. Plasma noradrenaline (NA) and arginine vasopressin (AVP) levels were examined at baseline and 10 min after tilt, with subsequent calculation of increases in plasma NA and AVP levels in this 10 min. Correlation coefficients were calculated among these assessment parameters. Results SDS significantly correlated with % maximum decrease in SBP ( r = 0.344, p = 0.02), but not with H/M ratios in both images and increases in plasma NA and AVP levels. SHAPS did not correlate with the change in SBP, H/M ratios in both images, or plasma NA and AVP levels. Conclusion Depression was correlated with the % maximum decrease in SBP during a 10-min HUT, but anhedonia did not show this relationship. This suggests that depression and anhedonia may have different pathophysiological backgrounds in drug-naïve PD patients.