S1 Dataset -

Introduction
Identifying various interacting risk factors for suicidality is important to develop preventive measures. The Interpersonal-Psychological Theory of Suicidal Behavior (IPTS) postulates suicidal ideation resulting from the occurrence of Perceived Burdensomeness (PB) and Thwarted Belongingness (TB). Suicidal behavior ultimately occurs if people have a Capability for Suicide. In past studies, the validity of TB was often not empirically confirmed, questioning which of the aspects of TB are central and related to suicidal ideation and whether applied measurement methods adequately capture the construct.
Method
Using a sample of 3,404 individuals from different clinical and nonclinical settings, 30% (1,023) of whom reported suicidal ideation, two network analyses were conducted on the Interpersonal Needs Questionnaire (INQ) and a variable mapping suicidal ideation.
Results
Analyses revealed that some items of the INQ were not related to suicidal ideation and the most central items did not have the strongest associations to suicidal ideation.
Conclusion
Based on these results, a shortened version of the INQ with the four items that showed the strongest associations with suicidal ideation in the network analyses was suggested.