Loneliness and Suicidal Ideation/Behaviour: A Longitudinal Study in a Large German Population Sample.

Recent representative studies from Germany report that between 16% and 36% of the population regularly experience loneliness. Available research findings indicate a significant positive association between loneliness and suicidal ideation and/or behaviour. The aim of the present longitudinal study was to investigate whether loneliness at baseline (T0) is prospectively associated with suicidal ideation and/or behaviour at follow-up (T1), independent of gender, social circle, depression, anxiety, stress and prior lifetime suicidal ideation and/or behaviour. Data were obtained via an online survey in a repeated-measures design in a large German population sample (N = 4277; 18-89 years of age), divided into four age groups (18-29, 30-45, 46-65 and 66-89 years). In order to examine the association between loneliness and suicidal ideation and/or behaviour, three-step hierarchical regression analyses were conducted in each age group, respectively. The regression models explained between 25.2% and 39.3% of the variance in T1-suicidal ideation and/or behaviour. Loneliness proved to be significantly associated with T1-suicidal ideation and/or behaviour, beyond affective symptoms, social circle and previous suicidal ideation and/or behaviour. The results underscore the importance of loneliness as a relevant component of suicidal ideation and/or behaviour in the German population. The findings emphasise the need to address loneliness in suicide risk assessment.