Globally, there are growing concerns about rates and consequences of loneliness, especially among older adults. In response, 2018 saw the launch of a UK loneliness strategy and the first minister for loneliness in the world appointed. In the USA, the National Academies of Sciences, Engineering, and Medicine set up a special committee to examine the problem. Demographic shifts suggest that the numbers experiencing loneliness are likely to increase.

Currently, there is inadequate causal evidence of the consequences of loneliness but associations with poor health and wellbeing have been established. The evidence shows associations with depression, anxiety, non-communicable diseases, poor health behaviours, stress, sleep, cognition, and premature mortality (with the evidence especially strong for depression). 

However, further work is required to establish causality between loneliness and specific health outcomes, and vice versa, as well as to investigate social consequences that remain unclear.