INVESTIGATING THE INTERRELATIONSHIP BETWEEN SLEEP DISTURBANCES AND MOOD DISORDERS IN NEURODEGENERATIVE CONDITIONS

Abstract

This study investigates the complex interrelationship between sleep disturbances and mood disorders in individuals with neurodegenerative conditions, including Parkinson’s disease (PD), Alzheimer’s disease (AD), and mild cognitive impairment (MCI). Utilizing a mixed-methods experimental design, the research combined quantitative physiological and biochemical analyses with qualitative psychological evaluations over a longitudinal six-month period. Sleep patterns were assessed using polysomnography and actigraphy, while mood and affective symptoms were measured through standardized clinical scales such as the Hamilton Depression Rating Scale (HDRS), Beck Depression Inventory (BDI-II), and Pittsburgh Sleep Quality Index (PSQI). Biochemical assays of cortisol and melatonin were conducted to explore neuroendocrine alterations associated with sleep–mood interaction. Statistical models, including correlation, regression, and structural equation modeling, revealed significant associations between impaired sleep efficiency, elevated cortisol levels, and depressive symptom severity (p < 0.05). The findings confirmed that sleep fragmentation and prolonged REM latency were predictive of emotional dysregulation, while improved sleep quality corresponded with reduced depressive intensity. Qualitative interviews further reinforced the bidirectional nature of this relationship, as participants reported fatigue, irritability, and cognitive dullness following nights of poor sleep. The integrated results suggest that disrupted circadian and neuroendocrine regulation mediates the link between sleep and mood disorders in neurodegenerative populations. These outcomes emphasize the importance of incorporating sleep-focused therapeutic interventions and continuous sleep monitoring into the management of neuropsychiatric comorbidities. Overall, the study highlights sleep health as a vital component in sustaining emotional stability and neurocognitive function, offering new insights for early intervention and patient-centered care strategies.