Loneliness is a concept within which two different phenomena are distinguished-positive (solitude) and negative (isolation) loneliness, but most often the concept of loneliness has negative connotations.

The problem of defining loneliness is connected with the variety of interpretations of this concept among different researchers: the feeling of loneliness and social isolation; the painful experience of forced isolation and voluntary solitude associated with existential search. The feeling of loneliness performs a regulatory function and is included in the feedback mechanism that helps the individual to regulate the optimal level of interpersonal contacts. However, physical isolation of a person does not always lead to loneliness.

Loneliness can be experienced by a young man or a girl who cannot find a suitable partner, or an elderly person who has lost friends and relatives and does not know how to find a common language with people. Loneliness is often experienced by people with an inert nervous system, who have difficulty quitting