Methods: Littell et al.’s (2008) systematic review process was used as a framework to organize, synthesize, and critique findings for a systematic review study on loneliness interventions for non-elderly adults. A comprehensive electronic search was conducted using several relevant databases (CINAHL, Pubmed, PsycINFO, and Social Work Abstracts) and keywords and index terms were searched using relevant terms associated with three concepts: age, loneliness outcome, and intervention study. Study selection was limited to studies conducted in English, assessed a primary outcome measure of loneliness, and included a population of non-elderly adults between ages 18 to 64.
Results: Out of 5,813 studies initially identified for title and abstract screening, 264 studies underwent full-text review by two independent reviewers, with conflicts being resolved by a third reviewer. Sixty-nine studies met inclusion criteria. Pairs of reviewers extracted and synthesized data from the included studies such as research design, sampling techniques, intervention type, and outcomes and will be examined for patterns of evidence. Results are grouped by primary sub-populations in which interventions were conducted; groupings included immigrants and refugees, people with mental illness, military members, people with chronic physical illness, new parents, and other marginalized groups. We found that in general, interventions to reduce loneliness were more effective in some populations (e.g., military members) than in others (e.g., marginalized groups). We also found a wide variety of study methods, measures of loneliness, and overall methodological rigor.
Conclusions and Implications: Expected outcomes of this systematic review are 1) evaluation of elements of successful interventions to reduce loneliness during adulthood; and 2) informing clinical social work practice around programs that reduce loneliness and its consequences among specific sub-populations of non-elderly adults.