The clinical significance of loneliness: a literature review.

Satisfying social relationships are vital for good mental and physical health. Accordingly, we recommend that the alleviation and prevention of social relationship deficits be a key focus of clinicians. In this review, we focus on loneliness as a crucial marker of social relationship deficits and contend that loneliness should command clinicians' attention in its own right--not just as an adjunct to the treatment of other problems such as depression. With a particular focus on the adolescent developmental period, this review is organized into five sections: Drawing on developmental and evolutionary psychology theories, the nature of social relationships and the function they serve is first discussed. In the second section, loneliness is introduced as an exemplar of social relationship deficits. Here a definition of loneliness is provided, as well as an explanation of why it may pose a situation of concern. This is followed by a review of the prototypic features of loneliness through examination of its affective, cognitive, and behavioral correlates. The fourth section includes a review of theories related to the antecedent and maintenance factors involved in loneliness. Finally, methodological and theoretical considerations are addressed, and conclusions and proposals for future research directions are put forth.