A large review of many studies shows that feeling lonely is connected to a higher chance of developing Alzheimer's disease. The research found that people who feel lonely are about twice as likely to get Alzheimer's compared to those who are not lonely.
The same review also found strong links between loneliness and suicidal thoughts and actions. People who felt lonely had a much higher chance of having suicidal thoughts, making plans, or trying to take their own life. The risk was highest for suicide itself.
Loneliness was also connected to feelings of being trapped, hopeless, and having trouble sleeping. These feelings often happen together and create a risky profile for both Alzheimer's and suicide.
It is important to know that this research shows links, not that loneliness directly causes these problems. The findings suggest that watching for loneliness, stress, and sleep issues could help protect people's mental and brain health.