26 Scientific American, May 2020 Illustrations by Galen DaraIT IS TIME TO START ANEW. More than a century after neuropathologist Alois Alzheimer gave the first
scientific talk describing the disease that bears his name today, we have no good treatments for this thief
of minds, and we certainly have no cure. Today 40 million to 50 million people worldwide suffer from
Alzheimer’s disease and other dementias. The drugs doctors have tried, aimed at a single type of lesion,
have repeatedly and agonizingly fallen short. Now scientists are beginning to say it is high time for a fresh
approach to the illness.
Patients and their families, of course, have known this for decades. To begin this special section, a hus-
band describes losing his wife to this ailment, and the utter devastation it wreaked on her, on him and on
their family ( page 28 ). Then we turn to the spectrum of disease causes, ranging from problems within the
brain to the environment outside. Neuroscientists have identified five areas—such as the brain’s immune
reactions—that have received relatively little attention yet may hold the seeds of new hope ( page 30 ). We
also take a hard look at the “amyloid hypothesis” that has dominated the search for treatments and whether
it still holds sway ( page 34 ). Another overlooked area is research into women, who have a much higher
risk than men of developing the disease, and our next story chronicles new studies of the roles played by
estrogen and menopause in mental decline ( page 37 ). Finally, we examine recent research that shows that
air pollution raises the risk of Alzheimer’s to a startling degree and explore the path between dirty air and
brain destruction ( page 42 ). — Josh FischmanTHE FUTURE OF MEDICINE
A NEW ERA FOR
ALZHEIMER’S