In the new movie Still Alice, Julianne Moore plays a linguistics professor diagnosed with early-onset Alzheimer's disease. Her performance has drawn rave reviews, earning her an Academy Award.
The movie also has doctors talking, such as Richard D. King, MD, PhD, an Alzheimer's specialist at Â鶹ѧÉú¾«Æ·°æ. "If a movie can raise awareness and show the humanity of the disease, that is very useful," he says.
Moore's character develops a relatively rare form of early-onset Alzheimer's at age 50. King says the majority of people who develop Alzheimer's are over age 65, and the risk nearly doubles with each successive decade. "The biggest risk factor is age."
Family history, a central theme of Still Alice, is also a risk factor. King says, "When individuals develop Alzheimer's disease in their 40s or 50s, it indicates a very strong genetic influence."
New research suggests other factors may precede the onset of the disease. A recent found that depression and behavioral changes were more likely in people who later developed Alzheimer's.
"Memory symptoms are the most troubling and most noticeable," King says. "But the changes in brain structure associated with Alzheimer's disease start decades before memory symptoms are noticed."
For the study, researchers at the Washington University School of Medicine in St. Louis evaluated nearly 2,500 people 50 and older. About half of the people in their research were people with Alzheimer's disease. They found that those who developed dementia were more likely to have experienced mood and behavioral changes first.
Senior author Catherine M. Roe, PhD, wrote, "We still don't know whether some of these symptoms, such as irritability and sadness, are due to people realizing on some level that they are having problems with memory and thinking, or whether these symptoms are caused directly by Alzheimer's effects on the brain."
It's also worth noting that depression and appetite loss are symptomatic of many other illnesses.
"What you don't want to do is tell anyone who is 50 and depressed with appetite loss, 'You have Alzheimer's,'" King says.
But a study like this can help doctors do a better job in identifying possible early symptoms of Alzheimer's.
This story was updated on February 23, 2015.