The BBC Loneliness Experiment conducted in 2018 was the biggest survey ever to explore the subjective sensation of loneliness, with over 55,000 individuals taking part. The popularity of this study highlighted the effects that loneliness (“subjective social isolation”) and objective social isolation can have on an individual’s physical and psychological wellbeing (Holt-Lundstad, 2015).
An overview by Leigh-Hunt (2017) summarised existing reviews into health implications associated with both forms of social isolation and found links with cardiovascular disease, premature death, suicide death and depression among others factors. Further findings showed that the adverse effects of social isolation are 8 times higher in those with mental health diagnoses compared to the general population (Meltzer, 2013).
Globally, governments and health bodies have taken steps to reduce the spread and impact of social isolation at a national level, but the impact of these interventions for those who are affected most, have been unclear. As such, this systematic review by Ma et al. (2019) provides a comprehensive overview of published randomised controlled trials (RCTs), the gold-standard of clinical studies, to explore the efficacy of interventions targeted toward reducing social isolation in clinical populations.
This systematic review distilled the outcomes of interventions specifically targeted towards reducing subjective or objective social isolation, or both, in clinical populations. Searches were made in July 2017 using electronic databases (Medline, Web of Science, PsychINFO, Open Grey) and included peer-reviewed journals and grey literature.
Inclusion criteria were the following:
- Randomised-controlled trials (RCTs) with no restrictions on publication dates, language or country of origin
- Comparison groups were either a control group, alternative intervention, waiting list sample or no treatment sample, or a combination of the aforementioned
- Social isolation was either a primary outcome or primary outcomes were not distinguished
- Participants’ primary diagnosis was of mental ill health.
Studies were excluded if:
- Participants had a learning or cognitive disability, including dementia or Autism Spectrum Disorder
- Social isolation was a secondary outcome
- Participants with a diagnosis of substance misuse
- Participants primary diagnosis related to physical health, including co-morbid diagnosis with mental illness.
Thirty studies met the criteria of this review; conducted in the USA, Europe, China, Canada and Israel. Eleven studies explored objective social isolation, 15 explored subjective social isolation and 4 investigated both. Only six studies stated social isolation as a primary study outcome.
Sample sizes ranged from 21 to 357 participants. 13 studies provided 1-on-1 interventions, nine were group-based interventions, four used a combination of group and individual interventions and four were internet-based. Effect sizes were not reported due to the number of studies which did not include this in their results.
A mixed methods intervention was the most common approach to reduce both subjective (6 studies) and objective social isolation (8 studies), with changing cognitions also being a common method for subjective social isolation. Other intervention approaches included supported socialisation, social skills training and psychoeducation. No studies used wider community approaches.
Overall, the majority of interventions found no statistically significant improvement compared to controls or alternative intervention groups. The number of studies per intervention approach was small and therefore the number of studies reporting a significant improvement in social isolation appeared to be at proximal to the chance-odds.
However, 11 subjective social isolation studies reported other relevant outcomes, as did 11 objective social outcome studies. Respectively, seven and ten of these studies reported positive results in depression, social anxiety, progression towards personal goals and quality of life.
The authors conclude that:
Current evidence does not yet clearly support scaled-up implementation of any types of intervention for subjective or objective social isolation in mental health services.
The authors acknowledge the variability in terms of quality, intervention approach and participants in the included studies, making definitive inferences difficult.
Strengths and limitations
The authors of this review include leaders in the field of both subjective and objective social isolation and provide a timely update of the efficacy of interventions offered to clinical populations to overcome social isolation. The review provides a clear and rigorous account of how the systematic review was conducted, using best practice approaches throughout and provides a robust summary of the quality and methods used within the included studies.
As pointed out by the authors, the included studies were exceptionally variable and only six of the studies expressly stated that social isolation was a primary outcome measure. There is evidence to suggest that demographics may moderate loneliness, however the authors do not comment on efficacy of interventions between countries or gender.
Implications for practice
Should this new evidence have an impact on practice?
Those involved in care plans to reduce social isolation must be mindful that effective interventions are still at the early stages of development, with interventions for subjective isolation appearing to be particularly challenging. However, such targeted interventions may improve other related aspects of individuals wellbeing.
What changes should be made as a result of these new findings?
Despite most studies here finding no statistically significant difference between their intervention and comparison groups, it would be helpful for these interventions to be replicated to check for reliability of these outcomes given the small number of studies meeting the review criteria.
Despite social isolation receiving increased attention in recent years, it is clear from this review that research is still playing “catch-up” to identify ways in which to reduce its occurrence and therein mitigate its negative effects on wellbeing. As such, further interventions should continue to be published using an Open Science approach so that researchers and healthcare professionals are kept informed about avenues explored and that the information can continue to be distilled to accelerate progress in this subject area. To aid clarity, future research should aim to replicate existing study designs where possible.
What new research avenues does this evidence open up?
The authors consider using a wider community approach to reduce social isolation. This provides an opportunity for some pioneering research in the subject area. Additionally with time, a meta-analysis would be very welcome in order to empirically investigate the effect sizes of these interventions, as it was not possible to do with the current studies available according to the authors.
Conflicts of interest
Ma, R., Mann, F., Wang, J. et al. (2019). The effectiveness of interventions for reducing subjective and objective social isolation among people with mental health problems: a systematic review. Soc Psychiatry Psychiatr Epidemiol. https://doi.org/10.1007/s00127-019-01800-z
BBC Radio 4 The Anatomy of Loneliness – Who feels lonely? The results of the world’s largest loneliness study (2018). Last accessed 14th January 2020.
Holt-Lunstad, J., Smith, T. B., Baker, M., Harris, T., & Stephenson, D. (2015). Loneliness and Social Isolation as Risk Factors for Mortality: A Meta-Analytic Review. Perspectives on Psychological Science, 10(2), 227–237. https://doi.org/10.1177/1745691614568352
Leigh-Hunt, N., Bagguley, D., Bash, K., Turner, V., Turnbull, S., Valtorta, N., & Caan, W. (2017). An overview of systematic reviews on the public health consequences of social isolation and loneliness. Public Health, 152, 157-171. https://doi.org/10.1016/j.puhe.2017.07.035
Meltzer, H., Bebbington, P., Dennis, M.S. et al. Feelings of loneliness among adults with mental disorder. Soc Psychiatry Psychiatr Epidemiol 48, 5–13 (2013) doi:10.1007/s00127-012-0515-8