The association between loneliness and other constructs of social connectedness and the probability of desire for hastened death, euthanasia and assisted suicide: systematic review

Abstract

Background
Euthanasia and assisted suicide (EAS) requests are common in countries where they are legal. Loneliness and social isolation are modifiable risk factors for mental illness and suicidal behaviour and are common in terminal illness. Our objective was to summarise available literature to clarify whether these and related measures of social connectedness might contribute to requests for EAS.

Methods
We conducted a pre-registered (PROSPERO CRD42019160508) systematic review and narrative synthesis of quantitative literature investigating associations between social connectedness and a) requested/actual EAS, b) attitudes towards EAS, and c) a desire for hastened death (DHD) by searching six databases (PsycINFO, MEDLINE, EMBASE, Scopus, Web of Science, Google Scholar) from inception to November 2022, rating eligible peer-reviewed, empirical studies using the QATSO quality assessment tool.

Results
We identified 37 eligible studies that investigated associations with a) requested/actual EAS (n = 9), b) attitudes to EAS (n = 16), and c) DHD (n = 14), with limited overlap, including 17,359 participants. The majority (62%) were rated at medium/high risk of bias. Focussing our narrative synthesis on the more methodologically sound studies, we found no evidence to support an association between different constructs of social connectedness and requested or actual EAS, and very little evidence to support an association with attitudes to EAS or an association with DHD.

Conclusions
Our findings for all age groups are consistent with a those of a previous systematic review focussed on older adults and suggest that poor social connectedness is not a clear risk factor for EAS or for measures more distally related to EAS. However, we acknowledge low study quality in some studies in relation to sampling, unvalidated exposure/outcome measures, cross-sectional design, unadjusted analyses, and multiple testing. Clinical assessment should focus on modifying established risk factors for suicide and EAS, such as hopelessness and depression, as well as improving any distressing aspects of social disconnectedness to improve quality of life.