Could loss of interest be sign of dementia risk?

"Apathy can be very distressing for family members, when people no longer want to get together with family or friends or don't seem interested in what they used to enjoy," said study author Meredith Bock, M.D., of the University of California, San Francisco. "More research is needed, but it's possible that these are signs that people may be at risk for Alzheimer's disease and could benefit from early interventions and efforts to reduce other risk factors."

The study involved 2,018 adults with an average age of 74. None had dementia. At the start of the study, researchers measured apathy using a survey with questions such as "In the past four weeks, how often have you been interested in leaving your home and going out?" and "In the past 4 weeks, how often have you been interested in doing your usual activities?" Participants were then divided into three groups: those with low, moderate and severe apathy. After nine years, researchers determined who had dementia by looking at medication use, hospital records and results on cognitive tests.

By the end of the study, 381 participants, or almost 19%, developed dementia. In the low apathy group, 111 out of 768 people, or 14%, developed dementia, compared to 143 out of 742 people, or 19%, in the moderate apathy group. In the severe apathy group, 127 out of 508 people, or 25%, developed dementia. After adjusting for age, education, cardiovascular risk factors and other factors that could affect dementia risk, they found that people with severe apathy were 80% more likely to develop dementia than people with low apathy.

Greater apathy was also associated with worse cognitive score at the beginning of the study.

"While depression has been studied more extensively as a predictor of dementia, our study adds to the research showing that apathy also deserves attention as an independent predictor of the disease," Bock said. "In fact, we believe that apathy may be a very early sign of dementia and it can be evaluated with a brief questionnaire."

A limitation of the study is that an algorithm was used to diagnose dementia, which may not be as sensitive as an in-depth evaluation by a doctor.