Psychiatric symptoms during l-dopa therapy for Parkinson's disease and their relationship to physical disability

Fifty patients attending a neurological outpatient clinic for Parkinson's disease were assessed by standardized methods for both physical and psychiatric symptoms. The patients then received treatment with L-dopa with carbidopa or anticholinergic drugs and/or amantadine. During the following six-month period the subjects were assessed at intervals, both physically and psychiatrically. Forty patients were followed up for the full six-month period. The severity of physical signs and affective symptoms was shown to be significantly related at several stages of the investigation. Initially, the patients showed a high psychiatric morbidity. During treatment, 22 patients developed a depressive disorder, 12 or which had a history of previous depressive episodes. By contrast, of the 11 patients who showed very few affective symptoms during follow-up, none had a history of depression. Of the 22 patients with a depressive disorder, only two were in the anticholinergic/amantadine group, compared with nine and 11 in the other groups. L-dopa was not an effective antidepressant agent. The probable relevance of the findings of the study to the management of patients with Parkinson's disease is outlined.