The Pros and Cons of New Drugs to Treat Alzheimer’s Disease

While humans are living longer –­ a child born in 2021 on average could expect to live to 71 –­ we haven’t figured out how to beat one of the worst scourges of aging: Alzheimer’s disease. Afflicting an estimated 36 million people worldwide, it’s the most common form of dementia, a loss of cognitive functioning severe enough to interfere with daily life. Researchers have yet to find a drug that reverses its progressive destruction of memory, thinking skills, and, if sufferers live long enough, the ability to swallow and breathe. Two new treatments have emerged that slow the rate at which patients decline. They do that modestly and come with downsides. Still, their success has provided a rare burst of hope for the field of Alzheimer’s research.

It’s not clear. Researchers think that the buildup of abnormal proteins seen in the brains of Alzheimer’s patients plays a central role. One, called amyloid, forms so-called plaques around brain cells. Their presence alone doesn’t seem to trigger cognitive decline, given that some people with normal mental functioning have them. A second protein, tau, creates tangles within brain cells. And a third suspect, brain inflammation, is thought to contribute in some way, perhaps in an intermediary role. Whatever the precise mechanisms, over time, neurons – cells that send messages throughout the brain and the rest of the body – stop working and die.