Loneliness and Its Associated Factors in Individuals With Intellectual Disability and Borderline Intellectual Functioning: A Systematic Review.

Only four databases were searched and only English or Spanish papers were included, so relevant studies may have been missed. The prevalence figures are simple averages across very different studies, not tested estimates of how common loneliness is in the population. The 40 studies defined and measured loneliness differently, and some asked a single question. People may under-report loneliness when asked directly, so the true figure could be higher. Almost all included studies were observational. They show what goes with loneliness, not what causes it, and the authors' own account of how the factors connect is described as tentative and conceptual. Most participants had mild or moderate intellectual disability, so this says little about people with the highest support needs. Evidence on people with borderline intellectual functioning is very thin: one prevalence study, three studies in total, and some data pooled with people who have intellectual disability. Samples were mostly white; only six studies reported participants' ethnicity, ranging from 50% to 91.4% white. The intervention evidence rests on small studies and a single pilot randomised trial.

The work was funded by the industrial doctorates plan of the Generalitat de Catalunya, carried out in collaboration with Fundació per a persones amb Discapacitat de Menorca, a disability foundation. The authors declare no conflicts of interest.

Do not read this as support for social-skills training or befriending programmes. The one social-skills trial included found no significant change in loneliness and the befriending trial found no significant improvement either, while the review's most consistent associations were with income, employment, housing, health and safety rather than with individual skill.