Neuropsychiatric Manifestations in Parkinson’s Disease and Other Lewy Body Diseases

Parkinson’s disease (PD) represents a spectrum of Lewy body diseases, including PD with dementia (PDD), dementia with Lewy bodies (DLB), and related disorders. The broad array of neuropsychiatric symptoms that manifest in these Lewy body diseases typically encompass mood, cognitive, and behavioral concerns, such as depression, hallucinations, delusions, and impulse control disorders. While motor symptoms take center stage in Lewy body disease, these neuropsychiatric symptoms also bear significant importance, necessitating thorough assessment and treatment. Proactively addressing these issues through appropriate interventions can substantially enhance patients’ overall quality of life. In this chapter, I will explore the clinical manifestations, underlying brain pathology, and treatment strategies related to these varied neuropsychiatric symptoms. Differing somewhat from symptoms seen in the realm of psychiatry, these symptoms require consideration of behavior rooted in organic factors rather than solely psychological ones. The neuropsychiatric symptoms observed in PD and other Lewy body diseases serve as a gateway to explore the realm of organic mental phenomena.