The association of perceived stress and the frequency and severity of non-motor symptoms in Parkinson’s disease

Abstract

Objective: While Parkinson’s disease (PD) is predominantly a motor disease, non-motor symptoms (NMS) are a prominent feature. When an individual perceives stress two endocrine responses become active, the hypothalamic-pituitary-adrenal axis and the sympathetic-adrenal-medullary axis, which exert effects on numerous body systems. The effects of these responses have previously been associated with negative states in people without PD, including depression and anxiety, and therefore could be associated with NMS in people with PD. The objective of this study was to assess the effects of perceived stress on both frequency and severity of NMS in PD. Methods: Individuals with prevalent idiopathic PD (n¼98) were recruited into this ongoing observational study in South East Queensland, Australia. The Non-Motor Symptoms Scale (NMSS) was used to assess severity and frequency of NMS, and the Perceived Stress Scale-14 (PSS-14) to assess stress. Bivariate corre- lation was used to measure the association between PSS-14 and both severity and frequency of the NMS. Results: Higher perceived stress scores were significantly associated with both severity (p< 0.001) and fre- quency (p¼0.047) of NMS. Stress was significantly associated with the severity of multiple NMS, the most prominent were loss of interest, anxiety, depression, flat moods and lacking pleasure (all p< 0.001). With regards to NMS frequency, stress was significantly associated with anxiety, depression, flat moods, lacking pleasure, difficulty concentrating, forgetting tasks and nocturia (all p< 0.05). Conclusion: The preliminary findings of this study indicate positive associations between perceived stress and NMS frequency and severity in numerous domains, in particular mood and cognition. Furthermore, perceived stress is more highly associated with the severity of NMS rather than frequency. Better manage- ment of stress in persons with PD may improve NMS burden that may consequently have positive effects on quality of life. Further research would be required to determine the extent stress affects NMS.