If you’re older and lonely, your mental faculties may decline at a quicker rate. That’s the conclusion from new research presented recently at the Alzheimer’s Association International Conference 2015 in Washington, D.C.
In their study, researchers said they discovered that loneliness can be a key predictor of the rapid progression of dementia-related diseases. One of the earliest symptoms of dementia is cognitive decline, a gradual reduction in high-level functions like memory and problem-solving.
Although social isolation has long been linked with cognitive decline, it’s been unclear which causes which, or if both are caused by a third factor, such as depression.
The new study examined 8,300 adults age 65 or older over the course of 12 years. Participants came in for a memory test every two years. The researchers also measured age, sex, race, wealth, income, health conditions, strength of social network, and levels of depression.
One in six of the participants reported feeling lonely much of the time. Of these lonely individuals, nearly half experienced high levels of depression.
Over the 12 years, researchers said people who were lonely experienced cognitive decline at a 20 percent faster rate than people who were not lonely. This is the same rate of cognitive decline associated with high levels of depression itself. Even having a single symptom of depression was enough to cause an 8 percent increase in cognitive decline.
Researchers are unsure how loneliness and cognitive decline are linked, but plan to do follow-up studies to consider the matter. In the meantime, taking steps to avoid loneliness can be a practical way to slow cognitive decline in an elderly loved one.