The association of family, social and romantic loneliness in relation to suicidal ideation and self-injurious behaviours

Over 703,000 people die by suicide every year. The association between loneliness and self-injurious thoughts and behaviours has received increasing amounts of attention, with a significant link consistently being identified. However the impact that different types of loneliness have on physical and mental health remains under-researched. The current study aimed to explore how different forms of loneliness might be associated with self-injury, based on findings from existing theory-driven research. This cross-sectional online study investigated three types of loneliness (family, romantic, social) as well as loneliness as a unidimensional construct (global loneliness) in relation to suicidal ideation and several established variables associated with suicidal ideation (defeat, entrapment and depression). 582 participants (age 18-70 years) completed the survey between May and October 2021. Results showed that all forms of loneliness were associated with suicidal ideation, and all loneliness measures significantly, independently, moderated the association between entrapment and suicidal ideation. Furthermore, depression significantly mediated between family, romantic and global loneliness and suicidal ideation, but not social loneliness. The findings suggest that the quality and/or quantity of family, romantic and global relationships, should be explored when considering loneliness as a possible risk factor for suicidal ideation and may have a significant impact on mental and physical health. In particular, romantic loneliness may have a particularly adverse association with negative affect and suicidal ideation. Future work would benefit from replicating these findings longitudinally.