Fatigue, depression and sleep in Parkinson’s disease
Leora L. Borek, MD, Joseph H. Friedman, MD

Background: Parkinson’s disease (PD) is primarily considered to be a movement disorder and is diagnosed by its motor signs. However, the nonmotor aspects of PD are frequently more debilitating than the motor complications of PD. Fatigue is a poorly understood phenomenon that is prevalent in PD patients. Depression and poor sleep quality are common as well and are important sources of disability.

Objective: To determine whether fatigue was associated with depression and poor sleep quality in patients with idiopathic PD and to evaluate whether fatigue and sleep quality improved after treatment of depression in PD patients.

Methods: 49 non-demented patients with a diagnosis of idiopathic PD were referred from a movement disorders clinic for psychiatric evaluation by a geriatric psychiatrist. Patients were administered the Parkinson Fatigue Scale (PFS) and Hamilton Depression Rating (HAMD) scales. Fatigue was diagnosed with a score ≥ 2.95, according to the PFS, and depression was diagnosed using DSMIV criteria and a HAMD score > 14. The Pittsburgh Sleep Quality Index (PSQI) measured the quality of sleep; a score > 5 indicated poor sleep quality. PD patients who met criteria for depression were treated in an open label fashion with citalopram, paroxetine, sertraline, escitalopram, venlafaxine or mirtazepine, at therapeutic dosages. After 8 weeks, the PFS, HAM-D and PSQI were repeated. A 50% reduction in HAMD score qualified as treatment response. The Hoehn & Yahr staging measured PD severity and the duration of PD was measured from the year of PD diagnosis.

Results: The mean age of the patient was 65 ± 11.2 years with a mean PD duration of 7.7 ± 5.2 years. The mean stage of PD was 2.4 ± 0.9. 47% were female, 57.1% had fatigue, 30.6% were depressed and 65.3% had poor sleep quality. 86% had both fatigue and depression. 90% were taking levodopa, 57% were on a dopamine agonist medication, and 43% were on sleep medication. Fatigue significantly correlated with depression (r = 0.4, p < 0.01) but not poor sleep quality. Depression was significantly correlated with poor sleep quality (r = 0.3, p < 0.05). Fourteen out of fifteen depressed patients (93%) completed an eight week trial of antidepressant treatment and the HAMD scores decreased by at least 50% in all cases. Fatigue severity significantly improved from 3.7 to 2.5 (t = 3.0, df = 14, p < 0.01) and sleep quality significantly improved from 8.2 to 5.5 (t = 6.8, df = 12, p < 0.01) after antidepressant treatment. Fatigue, depression and poor sleep are common in patients with PD. When evaluating fatigue and sleep in PD patients, it is important to consider that depression may be a contributing factor. Fatigue and depression reduce the quality of life of PD patients and when present together, may both be treatable.