YOU’RE TELLING A FRIEND about a great new restaurant, but when you try to recall the name, all you can come up with is “It starts with a P.” Doctors say those lapses aren’t a sign of dementia—a general term referring to the symptoms of cognitive decline, including memory, language, and problem-solving skills—or Alzheimer’s disease, a specific brain disease that is the most common cause of dementia. But those occurrences can become more frequent as we age. And stress and depression, prevalent in