(TIME.com) -- Yes, there is a difference. Why one is more likely to trigger serious memory problems?
In a study published in the Journal of Neurology Neurosurgery and Psychiatry, Tjalling Jan Holwerda of the Free University Medical Center in Amsterdam found that participants who reported feeling lonely -- regardless of how many friends and family surrounded them -- were more likely to experience dementia than those who lived on their own.
The scientists focused on nearly 2,200 older adults living in Amsterdam, aged 65-86, who did not show signs of dementia and were not living in institutions such as nursing homes, and visited them twice over three years.
About half of the participants lived alone and 20% reported feelings of loneliness. Almost two-thirds of the elderly in the study were women.
Prior research suggested that having a supportive social network is linked with positive health outcomes, from psychological health to physical health, while lacking such support can be harmful. Indeed, a growing body of studies finds that loneliness itself can kill, typically by raising blood pressure and increasing risk for heart disease and stroke. High blood pressure is also a risk factor for dementia.
The Dutch study found that after adjusting for other relevant factors like age, feeling lonely raised the risk of dementia by 64%.
The research didn't distinguish between Alzheimer's, which accounts for 90% of dementia, and other types of the mind and memory-robbing illness.
But the authors caution that the results cannot prove loneliness causes dementia: in fact, the opposite could be true since dementia and its resulting changes in mood and brain function may contribute to some of the social withdrawal of loneliness.
"(L)oneliness may be a behavioral reaction to diminished cognition," the authors write in discussing their findings, because people who are losing their memories may withdraw from others, either due to embarrassment or confusion about how to handle social situations resulting from their brain impairment.
There is also the possibility that "loneliness may also lead to a lack of sensory and cognitive stimulation," which can be harmful because it reduces levels of nerve growth factors that are necessary for brain health. Both processes could also be occurring at the same time, leading to a vicious cycle in which dementia lowers social support, which then worsens the disorder.
The results add to evidence of the complicated relationship between perception and social engaging, suggesting that a person's perception of his situation, such as whether he feels lonely or not, may have a greater impact on health than objective measures such as whether he lives alone and is isolated from a social network.
Many people say they feel lonelier in a bad marriage than they do being single -- and people can certainly live alone but still have a large network of friends and family.
Research on stress similarly shows the importance of this perception of social connectedness: if you feel you have control over the stress in your life -- regardless of whether you actually do -- it can have less negative physiological and psychological impact on your health in terms of blood pressure and heart disease.
Of course, controlling whether you feel lonely or not can be difficult -- and becoming anxious that being lonely will worsen or cause dementia won't help, either. But the research increasingly suggests that if you do feel socially isolated, working to improve your social network may be an important first step toward improving your health.
This story was originally published on TIME.com.
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