Additional Supporting Information may be found in the online version of this article.

MDS_23699_sm_suppfig1.tif1982KSupporting Figure 1: PDQ-39 subscores for ndPD, sdPD, and dPD. Data are given as mean ± SD, *P < .01, **P < 0.001 (Mann–Whitney test). The PDQ-39 scores of the sdPD group fell between those of the ndPD and dPD patients, but the sdPD group only significantly differed from the dPD group in the subscore “emotional well-being,” thus indicating that the sdPD group qualitatively mimicked the low quality of life (QoL) of dPD patients (ADL, activities of daily living).
MDS_23699_sm_suppfig2.tif5282KSupporting Figure 2: The nonlinear relation between QoL measured by a disease-specific scale (PDQ-39) and severity of symptoms of depression assessed with the Beck Depression Inventory (BDI). Small changes in BDI scores in the range of ndPD and sdPD (BDI < 16) led to a rapid decline in QoL.
MDS_23699_sm_suppfig3.tif2542KSupporting Figure 3: The screening instruments BDI, HAM-D, MADRS, BAI (Beck Anxiety Inventory) and HAM-A (Hamilton Anxiety Rating Scale) significantly differed in all groups (ndPD, sdPD, and dPD) at P < .01. BDI items were divided into 12 cognitively affective symptoms (caBDI) and 9 somatic symptoms (sBDI) according to a model of Endler et al (Endler NS, Rutherford A, Denisoff E. Beck depression inventory: exploring its dimensionality in a nonclinical population. J Clin Psychol. 1999;55:1307–1312).
MDS_23699_sm_suppfig4a.tif2792KSupporting Figure 4A: Receiver operating characteristic (ROC) curves for 3 screening instruments and the different patient groups. A: ROC curves for discriminating ndPD from sdPD and dPD. B: ROC curves for discriminating dPD from sdPD and ndPD (AUC, area under the curve). Sensitivity, specificity, and positive and negative predictive values for each score are given in Web Tables 1 and 2. Results are displayed as ROC curves that plot the proportion of patients correctly classified as depressed against the nondepressed who were incorrectly classified as depressed. Steeper curves indicate better discrimination. We also estimated the AUC under the ROC curve. When performance is at chance, the ROC curve is a straight line, indicated by the dotted line in each panel. AUC ranges between 0.5 (chance performance) and 1.0 (perfect discrimination).
MDS_23699_sm_suppfig4b.tif1792KSupporting Figure 4B
MDS_23699_sm_authorroles.doc25KAuthor Roles and Disclosures

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