With the rise of online social networking, social relationships are increasingly developed and maintained in a digital domain. Drawing conclusions about the impact of the digital world on loneliness is difficult because there are contradictory findings, and cross-sectional studies dominate the literature, making causation difficult to establish. In this review, we present our theoretical model and propose that there is a bidirectional and dynamic relationship between loneliness and social Internet use. When the Internet is used as a way station on the route to enhancing existing relationships and forging new social connections, it is a useful tool for reducing loneliness. But when social technologies are used to escape the social world and withdraw from the "social pain" of interaction, feelings of loneliness are increased. We propose that loneliness is also a determinant of how people interact with the digital world. Lonely people express a preference for using the Internet for social interaction and are more likely to use the Internet in a way that displaces time spent in offline social activities. This suggests that lonely people may need support with their social Internet use so that they employ it in a way that enhances existing friendships and/or to forge new ones.

Background: Suicide and suicidal behaviour are global health concerns with complex aetiologies.Given the recent research and policy focus on loneliness, this systematic review aimed to determine the extent to which loneliness predicts suicidal ideation and/or behaviour (SIB) over time.Methods: A keyword search of five major databases (CINHAL, Medline, PsychArticles, PsychInfo and Web of Knowledge) was conducted. Papers for inclusion were limited to those using a prospective longitudinal design, written in English and which measured loneliness at baseline and SIB at a later time-point.Results: After duplicates were removed, 947 original potential papers were identified, with 22 studies meeting the review criteria. Meta-analysis revealed loneliness was a significant predictor of both suicidal ideation and behaviour and there was evidence that depression acted as a mediator.Furthermore, studies which consisted of predominantly female participants were more likely to report a significant relationship, as were studies where participants were aged 16-20 or >55 years at baseline.Limitations: There was considerable variability in measures, samples and methodologies used across the studies. Middle-aged adults were under-represented, as were individuals from minority ethnic backgrounds. All studies were conducted in countries where self-reliance and independence (i.e. individualism) are the cultural norm.Conclusions: Loneliness predicts later SIB in select populations. However, due to the heterogeneity of the studies further research is needed to draw more robust conclusions. Suicide death also needs to be included as an outcome measure. A focus on more collectivist countries is also required.

BackgroundRisk scales are used widely in the management of patients presenting to hospital following self-harm. However, there is evidence that their diagnostic accuracy in predicting repeat self-harm is limited. Their predictive accuracy in population settings, and in identifying those at highest risk of suicide is not known.MethodWe compared the predictive accuracy of the Manchester Self-Harm Rule (MSHR), ReACT Self-Harm Rule (ReACT), SAD PERSONS Scale (SPS) and Modified SAD PERSONS Scale (MSPS) in an unselected sample of patients attending hospital following self-harm. Data on 4000 episodes of self-harm presenting to Emergency Departments (ED) between 2010 and 2012 were obtained from four established monitoring systems in England. Episodes were assigned a risk category for each scale and followed up for 6 months.ResultsThe episode-based repeat rate was 28% (1133/4000) and the incidence of suicide was 0.5% (18/3962). The MSHR and ReACT performed with high sensitivity (98% and 94% respectively) and low specificity (15% and 23%). The SPS and the MSPS performed with relatively low sensitivity (24–29% and 9–12% respectively) and high specificity (76–77% and 90%). The area under the curve was 71% for both MSHR and ReACT, 51% for SPS and 49% for MSPS. Differences in predictive accuracy by subgroup were small. The scales were less accurate at predicting suicide than repeat self-harm.ConclusionsThe scales failed to accurately predict repeat self-harm and suicide. The findings support existing clinical guidance not to use risk classification scales alone to determine treatment or predict future risk.Electronic supplementary materialThe online version of this article (10.1186/s12888-018-1693-z) contains supplementary material, which is available to authorized users.