Sleep disorders and depression in patients with Parkinson's disease

Objectives - Sleep disorders and depression are frequent in patients with P arkinson's disease (PD). However, the exact prevalence and the causality ar e still unknown. Patients and methods - We interviewed 56 consecutive PD pa tients and 59 age-matched healthy controls concerning sleep disorders and d epression. Sleep Disorders Questionnaire (SDQ) and Zung Depression Scale (Z DS) were used as standardized valid and reliable psychometric tests. Result s - Patients with PD had significantly higher values in the clinical-diagno stic scale narcolepsy (P=0.01), correlating with the L-dopa dose (P=0.007). Concerning sleep apnea (P=0.49), psychiatric sleep disorder (P=1.00) and p eriodic limb movement disorder (P=0.12), no significant difference could be identified. PD patients showed significantly higher depression scores than healthy control subjects (P=0.01), increasing with the duration of PD (P=0 .04). Conclusion - The significant higher narcolepsy score in PD patients m ust be seen due to dopaminergic medication and PD-specific neurodegeneratio n and immobility rather than due to narcolepsy. This leads to the conclusio n that extreme caution is advised when carrying out the SDQ and interpretin g the results in various persons and patient groups with motor problems. Th e strong association of depression, disease severity and sleep disorders in PD patients underlines the importance of identifying and treating both con ditions in these patients.