Alzheimer’s still has no treatment that reverses it
It drives about 60–70 percent of dementia cases. Roughly 50 million people lived with it worldwide by 2020, yet medicines only ease symptoms for a time. Plaques and tangles build while memory of recent events frays first.
Alzheimer’s disease is a neurodegenerative condition and the most common cause of dementia, accounting for roughly 60–70 percent of cases. Early trouble remembering recent events gives way to language problems, disorientation, mood swings, lost motivation, self-neglect, and behavioral change; people often withdraw, then lose bodily functions, and eventually die. Median life expectancy after a dementia diagnosis runs about three to twelve years. As of 2020 about 50 million people worldwide had Alzheimer’s; it usually begins after 65, though up to 10 percent of cases are early-onset from the thirties to mid-sixties. It affects about 6 percent of people 65 and older, women more often than men, and carries an estimated global annual cost near US$1 trillion.
Causes remain poorly understood. Amyloid plaques and neurofibrillary tangles of malformed protein accumulate in cortex, disrupting cells until neurons die. The strongest genetic risk for common late-onset disease is the APOEε4 allele: between 40 and 80 percent of people with Alzheimer’s carry at least one copy, which roughly triples risk in heterozygotes and multiplies it about fifteenfold in homozygotes—though penetrance is incomplete, and Nigerian Yoruba populations famously lack the usual dose–onset link. Only 1–2 percent of cases stem from deterministic autosomal-dominant mutations in APP, PSEN1, or PSEN2; late-onset disease is about 70 percent heritable yet mostly sporadic. Other risks include head injury, depression, and high blood pressure.
No known therapy stops or reverses progression, though some drugs temporarily improve symptoms. Diet, activity, and social engagement may help lower cognitive-decline risk in aging generally. The disease is often sketched in mild, moderate, and severe stages, with the hippocampus hit early. Neuropsychology can flag mild cognitive difficulties up to eight years before clinical criteria are met; amnestic mild cognitive impairment is frequently seen as a prodrome. Named after Alois Alzheimer, who described it in 1906, the illness now ranks among the world’s leading killers—seventh in one global ranking for Alzheimer’s and related dementias—while research budgets climb into the billions.
Source: Alzheimer's disease
