Depression and parkinsonism in older Europeans: results from the EURODEP concerted action

Objective: The prevalence rate of depression among patients with Parkinson's disease (PD) has been estimated at 25%, although prevalence figures range between 7-76%. Relatively few studies on PD and depression are based on random samples in the general population. Some depressive symptoms can also be understood as symptoms of parkinsonism, and the current study aims to describe which 'overlap' symptoms can be identified in a community sample. Methods: Data are employed from the EURODEP collaboration. Nine study centres, from eight western European countries, provided data on depression (most GMS-AGECAT), depressive symptoms (EURO-D items and anxiety), parkinsonism (self-report of PD or clinical signs of PD), functional disability and dementia diagnosis. Results: Data were complete for 16 313 respondents, aged 65 and older; 306 (1.9%) reported or had signs of parkinsonism. The rate of depression was about twice as high among respondents with parkinsonism (unadjusted Odds Ratio 2.44, 95% Confidence Interval 1.88-3.17), also among those without functional disability. 'Overlap' symptoms between parkinsonism and depression, were represented by motivation and concentration problems, appetite problems and especially the symptom of fatigue (energy loss). However, principal component analysis showed that these 'overlap' symptoms loaded on different factors of the EURO-D scale. Conclusions: As among clinical patients with PD, depression is highly common in community dwelling older people with parkinsonism, even among those without functional disability. Although fatigue did not strongly relate to motivational symptoms, both types of 'overlap' symptoms possibly trigger a final common pathway towards a full depressive syndrome.