The Association of Anxiety and Depression with Sleep Disturbances in Parkinson's Disease

Background: Non-motor symptoms in Parkinson's disease (PD) consist of a wide spectrum of gastrointestinal impairment, urinary dysfunction, sleep disturbances, fatigue and psychiatric disorders. Mood disorders like anxiety and depression are linked to general well-being and overall quality of life, therefore influencing the amount and quality of restful sleep that the patients can achieve. Objectives: The aim of this study is to determine the prevalence and characteristics of anxiety and depression in PD and to identify the factors that correlate with sleep disturbances. Methods: We conducted a case-control study which included 131 PD patients and 131 controls. Descriptive data was collected, and validated scales and questionnaires regarding sleep, motor symptoms and symptoms related to anxiety and depression were administered. Patients were divided into groups by the presence or absence of sleep disorders ("bad sleepers" and "good sleepers") and by the presence or absence of anxiety and depression. Comparative analysis was performed. Results: PD patients reported more clinically significant depression than controls and those with concomitant sleep impairment scored higher on depression- and anxiety-specific scales than their better-sleeping counterparts. Age, motor status and sleep impairment were found to be factors associated with depression in PD patients. The presence of sleep disorders was also associated with anxiety. Conclusions: Depression and anxiety are frequent in PD and are associated with comorbid sleep disturbances.