Factors associated with depression in Parkinson's disease: a cross-sectional study in a Polish population

The aim of this study was to assess the prevalence and factors influencing depression in PD patients in a cross-sectional outpatient clinic - based Polish patients sample.

One hundred consecutive PD patients were included in this study; 35 of them fulfilled DSM-IV criteria for Major Depression and its severity was assessed with Montgomery-Asberg Depression Rating Scale (MADRS). A structured interview and a neurological examination, including Hoehn and Yahr scale (H-Y), Schwab-England disability scale, II, III, IV parts of Unified Parkinson's Disease Rating Scale (UPDRS), and Mini-Mental State Examination (MMSE) were performed. The parameters obtained were analysed between the depressed and non-depressed PD patients.

The prevalence of depression in PD in Polish population was established at the level of 35%. PD patients with depression scored significantly higher in all UPDRS scales (except for the subscale of clinical fluctuation) and in H-Y scale. PD with depression was also associated with longer PD duration, higher doses of L-dopa equivalents, patients' age, general impairment of daily living in Schwab and England disability scale, lower MMSE and higher clinical fluctuations. However, those six differences were insignificant.

Depression prevalence rate among PD patients in Polish population is slightly lower than in most of other published studies. This may result from strict selection criteria, use of specific outcome measures and restricted criteria for depression that were applied.