Meaningful social relationships are to loneliness what food is to hunger and water is to thirst. Loneliness, like hunger and thirst, is not eliminated or solved. It is temporally alleviated and must be continually addressed.

From The Guardian:

Loneliness is not the same as being alone. It is the response to an insufficiency of emotional closeness and connection.

Loneliness is not about numbers. It’s about the depth of the connection, the feeling that you are being seen and loved.

The cure for loneliness is intimacy, and the problem with intimacy is that it’s frightening. There’s a risk of being rejected or having to deal with conflict, and both these things can feel insurmountable, especially when a person has been lonely for a long time.

Loneliness alters your perception, magnifying any sense of social threat. What this means is that you tend to notice and remember difficult or awkward social encounters far more than those that run smoothly. Instances of perceived rudeness or rejection loom large, making the lonely person more withdrawn and less willing to reach out.

From The International Journal of Aging and Development:

Social relationships protect people against loneliness. Friendship qualities like intimacy and frequency of contact may vary throughout a person’s lifespan. Older people have fewer confident friends than younger people. However, older age groups report higher levels of satisfaction with their contact with friends. Research shows that the aspiration for contact with friends is more significant to loneliness than actual contact in all age groups. Dissatisfaction with contact with friends is strongly related to loneliness in all age groups.