Depletion of dopamine in Parkinson's disease and relevant therapeutic options: A review of the literature.

Parkinson's disease (PD) is a progressive neurodegenerative disorder that affects motor and cognition functions. The etiology of Parkinson's disease remains largely unknown, but genetic and environmental factors are believed to play a role. The neurotransmitter dopamine is implicated in regulating movement, motivation, memory, and other physiological processes.

Prevalence and incidence of major depressive disorder in Alzheimer's disease: findings from two databases.

Background: Reports on the frequency of major depression in Alzheimer's disease are conflicting, some suggesting that it is frequent, others suggesting that it is uncommon.

Methods: We examined the prevalence and incidence of symptom clusters meeting criteria for major depressive disorder (MDD) in two large series of cases diagnosed prospectively by NINCDS/ADRDA criteria as probable or possible Alzheimer's disease. Standard DSM-III-R criteria were employed at one site, the CERAD modification of DSM-III-R criteria at the other.