Loneliness is a phenomenon of the present time, and this negative experience is expected to increase. It differs from solitude, which is characterized as an objective state.
Loneliness results from subjective perception of social interactions, defined as subjective experience of lack of quantity and quality of social contacts. A distinction is made between emotional and social loneliness.
While emotional loneliness is due to the absence of a close interpersonal relationship with an individual, social is the absence of friends and ties in the social network. From the perspective of the ontogenetic development of an individual, these are periods of adolescence (especially its early stage) and then periods of older adulthood and old age, which are characterized as critical for experiencing loneliness.
Loneliness is associated with introversion, anxiety, lower self-esteem, and close association with depression. It has adverse health consequences, so interventions aimed at overcoming it are important.
In the theoretical interpretation of loneliness, evolutionary approaches highlighting its hereditary background and sociocognitive model, which point to hypersensitivity of lonely people to social threat, are applied. The challenge for future research is the existence of feelings of loneliness despite the involvement of people in virtual social networks, which is made possible by technological development.