Intolerance of uncertainty and suicidal ideation among Chinese college students: the mediating role of non-suicidal self-injury and the stage-specific moderating roles of perceived social support

Introduction Intolerance of uncertainty (IU) is increasingly recognized as a transdiagnostic risk factor for suicide-related outcomes. However, the mechanisms linking IU to suicidal ideation remain insufficiently understood. Objectives This study aimed to examine the association between IU and suicidal ideation, particularly regarding the role of non-suicidal self-injury (NSSI) and the protective roles of perceived social support from different sources, including family and friend support. Methods A cross-sectional survey was conducted among 2, 167 Chinese college students (68.6% females; M age = 18.91years, SD = 1.31). Participants completed measures of IU, NSSI, suicidal ideation, and perceived family and friend support. Results Results indicated: (1) IU was positively associated with both NSSI and suicidal ideation. (2) NSSI partially mediated the association between IU and suicidal ideation. (3) Perceived family support and friend support both moderated the direct association between IU and suicidal ideation, such that higher levels of support attenuated this direct association. (4) Regarding the indirect pathway, friend support moderated the association between IU and NSSI, whereas family support moderated the association between NSSI and suicidal ideation. Conclusion The present findings clarify a cognitive–behavioral pathway through which IU contributes to suicidal ideation and highlight perceived social support as a key protective resource that buffers this risk. By revealing differentiated roles of family and friend support across pathways, the study advances understanding of how stage-specific protective roles of perceived social support across the associations among IU, NSSI, and suicidal ideation.