The Hidden Epidemic: Apathy in Parkinson's Disease, Neurodegeneration, and the Aging Brain

Forty percent of Parkinson's patients will develop apathy. Not depression — a specific, measurable loss of the drive to initiate. Across Parkinson's, Alzheimer's, Lewy body dementia, and late-life depression, an estimated 8 million Americans are affected. There are zero approved treatments. The most commonly prescribed drugs may be making it worse.

• Why apathy is not depression — and why the distinction changes treatment
• Prevalence across neurodegeneration and the aging brain
• The neurobiology: a broken effort-reward circuit
• Caregiver burden, institutionalization, and mortality risk