Chapter 10: Neurocognitive Disorders

The text differentiates delirium from dementia, emphasizing delirium's acute onset, fluctuating course, and frequent diagnostic overlap with chronic neurocognitive conditions, while highlighting why recognition remains clinically challenging. Major dementia syndromes are explored in depth, including Alzheimer's disease with its amyloid and tau pathology, frontotemporal dementia characterized by behavioral and language variants, dementia with Lewy bodies and its relationship to Parkinson's disease motor features, and vascular dementia resulting from cerebrovascular insufficiency. The chapter incorporates contemporary neuroscience by discussing biomarker advances, structural and functional neuroimaging findings, and genetic risk factors such as apolipoprotein E status in Alzheimer's disease. Mild cognitive impairment is presented as a transitional state between normal aging and dementia, with evidence-based preventive approaches including physical exercise, nutritional interventions, and cognitive and social stimulation. Behavioral and psychological symptoms of dementia, including psychotic features, depressive episodes, agitation, and aggression, receive substantial clinical attention with discussion of both pharmacological and non-pharmacological management strategies. Emerging disease-modifying treatments, particularly anti-amyloid monoclonal antibodies, are reviewed alongside symptomatic medications and cognitive rehabilitation approaches. The chapter integrates neurobiology with clinical assessment and management, providing psychiatrists and trainees with a practical framework for diagnosis, staging severity, monitoring disease progression, and selecting appropriate interventions across the spectrum of neurocognitive decline.