The economic costs of loneliness: a review of cost-of-illness and economic evaluation studies.

<bold>Purpose: </bold>Loneliness and social isolation can occur at all stages of the life course and are recognized as a global health priority. The aim of this study was to review existing literature on the economic costs associated with loneliness and social isolation as well as evidence on the cost-effectiveness of interventions to prevent or address loneliness and social isolation.<bold>Methods: </bold>A bibliographic database search was undertaken in Medline, PsycINFO, CINAHL, and Embase, supplemented by a grey literature search and a reference list search. Papers were included that were published in English language in peer-reviewed literature in the past 10 years, reporting costs of loneliness and/or social isolation or economic evaluations of interventions whose primary purpose is to reduce loneliness and/or social isolation, including return on investment (ROI) or social return on investment (SROI) studies.<bold>Results: </bold>In total, 12 papers were included in this review, consisting of four cost-of-illness studies, seven economic evaluations and five ROI or SROI studies. Most studies were conducted in the UK and focused on older adults. Due to the inconsistent use of the terms loneliness and social isolation, as well as their measurement, the true economic burden can only be estimated to a certain extent and the comparability across economic evaluations and ROI studies is limited.<bold>Conclusions: </bold>The paucity of evidence that is available primarily evaluating the economic costs of loneliness indicates that more research is needed to assess the economic burden and identify cost-effective interventions to prevent or address loneliness and social isolation. [ABSTRACT FROM AUTHOR]