Project Summary Suicide is the 5th leading cause of death among children aged 5-11 (CDC, 2020). Rates of child suicide has increased by 68% in the last decade, with rates significantly higher among Black compared to white children (Bridge et al., 2018). The National Institute of Mental Health (NIMH) has identified suicide prevention as an urgent priority, particularly for groups at highest risk. Most studies of suicidality have been conducted in majority White samples, leaving the experiences of Black children left out of scientific efforts to reduce youth suicide. Thus, there is in urgent need for developmentally and culturally informed research on suicidality. In this application we propose to adapt a widely used model for understanding the development of suicidal thoughts and the transition from thoughts to behavior, the Interpersonal-Psychological Theory of Suicide (IPTS; Joiner, 2005), according to which hopelessness in the context of lack of belongingness and burdensomeness leads to suicidal ideation, and capacity to engage in self-harm leads to suicidal behavior. Components of the IPTS have been reliably measured in adolescents and children as young as 10 years (Horton et al., 2016; Roberts et al., 2020; Stewart, et al., 2017). The model was further elaborated to be relevant for Black youth by including exposure to systemic, structural, and interpersonal racism as risks for and racial socialization and identity as protective against suicidality (Robinson et al., 2021). We propose to test the reliability, validity, and stability of a developmentally and culturally informed IPTS model beginning in early childhood (age 4-6 years) in Black youth. The Pittsburgh Girls Study (PGS) is a 20-year longitudinal study of 2,450 women who were initially enrolled when they were between the ages of 5 and 8 years. We propose to enroll 300 Black offspring of PGS participants and will enrich the sample by recruiting children of mothers with a history of suicidal ideation and attempts, which have been measured prospectively for 20 years. We aim to recruit two age groups of children: 5–7-year-olds and 7–9-year-olds. Both groups will be assessed six times at 9-month intervals, through ages 10-12 years. This design will allow us to test the reliability, validity, and stability from early childhood to early adolescence of hypothesized constructs of the suicidal process measured across multiple systems. Along with data from parent- and self-report, heart rate variability and mood will be measured in response to age-appropriate probes: Cyberball, parent-child tasks, loss/failure tasks, and the Balloon Analogue Reaction Task, which are hypothesized to yield individual differences in loneliness, connectedness, self-worth and hopelessness, and impulsivity. Embedding a study of early childhood suicide phenotypes in Black children of PGS participants will allow robust tests of early risk and stability of suicidality in the context of culturally relevant risk and protect...