Depressive Symptoms in Parkinson Disease: Degree of Association and Rate of Agreement of Clinician-Based and Self-Report Measures

Depression in Parkinson disease (PD) is associated with faster disease progression, lower activities of daily living, and more severe cognitive impairment. Even mild symptoms of depression may impact outcomes in patients with PD. Nevertheless, a low rate of agreement has been reported between patient and clinician ratings of depression, suggesting that clinicians may underestimate depression in patients with PD. However, to accurately compare the rates of agreement, comparable estimates are needed so that patient and clinician ratings have similar meaning (eg, mild, moderate, severe, etc). The purpose of this study was to examine this question by investigating the degree of association and rate of agreement of levels of symptom severity among self-report and clinician ratings using established cutoffs that correspond to more comparable estimates of these levels for both patient and clinician. Our findings suggest that patient’s self-report of depressive symptoms was significantly correlated with clinician-based report irrespective of the stage of disease. Moreover, patients demonstrated a 72% rate of agreement with clinicians in classifying symptoms as asymptomatic, mildly symptomatic, or fully symptomatic, a rate significantly higher than the rate of 35% previously reported. This difference in rate of agreement may be accounted for using varying criteria for severity levels across the studies. Findings suggest that clinician and patient reports show a high rate of agreement across a range of depressive symptoms and that self-report measures may provide a relatively efficient means of detecting depressive symptoms especially if patients are disinclined to initiate their report.