Is dementia in Parkinson' disease related to chronic stress, anxiety, and depression?

Objectives: Stress, anxiety, and depression are known to be associated with the development of neurodegenerative disorders through interactions with the underlying pathophysiology. We hypothesized that the presence of these symptoms contributes to cognitive disturbances and dementia in Parkinson's disease (PD). The present study aimed to investigate the levels of stress, anxiety, and depression in PD patients relative to healthy individuals. Materials and Methods: Anxiety, stress, and depression levels were assessed using standardized questionnaires in PD without dementia (PDND, n = 30), PD with dementia (PDD, n = 28), and healthy controls (HC, n = 26). Arithmetic subtraction task was used as a stressor. Galvanic skin response, heart rate and salivary cortisol, and alpha-amylase were measured during baseline and after induced stress (arithmetic task). Results: Acute anxiety, acute stress, and depression levels were significantly higher in PDND compared to HC, whereas both acute and chronic anxiety, stress, and depression levels were significantly higher in PDD compared to PDND and HC. Cortisol and alpha-amylase levels were significantly higher in PDND compared to HC during both baseline and postarithmetic task. Posttask levels of cortisol were lower in PDD compared to PDND. Conclusion: This study concludes that higher levels of salivary cortisol and alpha-amylase at baseline and poststress task with normal levels of chronic stress and anxiety were associated with no dementia in PD. Presence of higher levels of acute, chronic anxiety, and stress along with depression with lower cortisol reactivity to stressor suggests onset of dementia in Parkinson's patients.