PROJECT SUMMARY Suicide is the 2nd leading cause of death among adolescents, and, alarmingly, rates have continued to increase over the past decade. With the current dearth of empirically supported psychosocial interventions for adolescent suicidal behavior, there is a great need to identify processes underlying risk for this outcome. Interpersonal negative life events (NLEs) have been linked to short-term risk for suicidal behavior (i.e., suicide attempts and deaths). However, how or why these interpersonal NLEs confer risk is currently unclear. Understanding the moderators and mechanisms of the link between interpersonal NLEs and suicidal behavior is crucial in order to identify when adolescents are most at risk and to develop interventions that can target these mechanisms and reduce suicidal behavior during these periods of risk. Interpersonal NLEs may lead to suicidal behavior through their impact negative emotional states (e.g., agitation) and social connectedness, and further magnified by rejection sensitivity, emotion regulation difficulties, and sleep disturbance. Although past studies have found these constructs to be linked with suicidal behavior, this research is limited in three key ways: (1) Most prior studies have examined long time periods (months and years), which lack the temporal resolution to examine these mechanisms on the time scale in which they unfold (hours and days). We will intensively (over hours and days) examine how interpersonal NLEs relate to suicidal behavior. (2) Little is known about the impact of the social system, such as the family unit, and what key collaterals (e.g., parents) are observing in the short-term leading up to their adolescent’s suicidal behavior. By including parental reports, this study will reveal parents’ awareness of their adolescents’ suicide risk and potentially identify how parents can help them during these high-risk times. (3) Most past work has been insufficiently powered to examine links with suicidal behavior (instead focusing on suicidal thoughts). We propose to examine how and why interpersonal NLEs confer risk for suicidal behavior using smartphone-based ecological momentary assessment (EMA) and wearable sensors (i.e., wrist actigraphy) among 600 adolescents and their parents recruited from three diverse sites (Brown, Old Dominion, Rutgers) during the month after discharge from acute psychiatric care. We will address three aims: Aim 1. Examine how interpersonal (particularly familial and peer) NLEs increase risk for suicidal behavior through increased negative emotion and decreased social connectedness. Aim 2. Examine how rejection sensitivity moderates the link from interpersonal NLEs to negative emotionality/decreased social connectedness. Aim 3. Examine how sleep disturbance and emotion regulation difficulties moderate links from increased negative emotions and decreased social connectedness to suicidal behavior. This work will significantly advance understanding of proximal risk for suicidal behavior in youth and how the field assesses and treats suicidal adolescents.

PROJECT NARRATIVE Suicide is the 2nd leading cause of death among adolescents. Interpersonal negative life events (NLEs) have been consistently linked to short-term risk for suicidal behavior, but it is currently unclear how or why these events confer risk. The current study will examine the moderators and mechanisms linking interpersonal NLEs to suicidal behavior using an intensive real-time monitoring (smartphone ecological momentary assessment + wearable actigraphy) design with a large sample of 600 adolescents and their parents, after discharge from acute psychiatric care from three diverse sites (Brown, Old Dominion, Rutgers) recruited and followed for a month.