Subthreshold depression in Parkinson's disease.

ABSTRACT

BACKGROUND: Quality of life in Parkinson patients with subthreshold depression could be improved if the prevalence and symptom profile were better understood. METHODS: Our study used standard DSM-IV and Judd criteria as well as motor, depression, and quality-of-life scales to investigate a sample of 110 nondemented Parkinson patients. This led to formation of nondepressed (48.2%), subthreshold depressed (25.5%), and depressed (26.4%) groups. RESULTS: Quality of life was seen to be significantly lower in subthreshold depressed patients than in the nondepressed, and there were differences in the frequency of depressive symptoms that partially overlapped with nonmotor symptoms of vegetative origin in Parkinson's disease (appetite, sleep disorders). Key measures of depression (diminished interest/pleasure) were more frequent in the depressed group compared with the subthreshold depressed, although the motor functions of these 2 groups did not differ significantly. CONCLUSIONS: The Beck Depression Inventory score ranging from 9 to 15 points differentiates subthreshold depressed from nondepressed and depressed patients best.