A prospective study of depression in French patients with Parkinson's disease. The Depar study

To investigate the prevalence and symptomatology of depression in Parkinson's disease (PD), we have studied 506 unselected patients attending the neurology services in French general hospitals during a 5 month period defined for prospective inclusion. 246 patients (48.6%) were suspected of depression according to different methods of evaluation and 168 (33.2%) were defined as definite or probable depression. According to the Montgomery and Asberg scale, 46 cases (9%) had a severity score suggestive of major depression. As a function of the cut-off score defined for severity, these patients represented from 23.2 to 43.7% of the depressive population with PD. There was no significant difference between depressed and non depressed PD patients as a function of the patient's current age or age at onset of PD. A significantly higher rate of depression was found among women with PD. A past history of depression was a risk factor for mood disorder after onset of PD. The severely depressed patients had a significantly longer duration of PD and a higher score of cognitive impairment than mildly or moderately depressed and non depressed patients with PD. Depressed patients had a significantly more advanced stage of disability than non-depressed patients with PD.