Many people struggle with loneliness because they live by themselves or spend most of their time alone. Others may be surrounded by people, yet still feel lonely. Whichever the case, loneliness is caused by the lack of connection that comes through relationships.
The presence of loneliness reflects a lack of emotional connection, not a lack of people. That is why some people feel lonely even in a crowd. One may also experience loneliness when a social group does not provide the support the person needs.