Project Summary Suicidal ideation (SI) is prevalent and impairing in youth and can lead to restrictive and intensive care. There is a critical need to develop and test scalable brief interventions conducive to enhancing least-restrictive, cost-efficient, and accessible support, and which target drivers of SI in youth. This R61/R33 application addresses this need via a brief intervention module for youth experiencing subacute SI (i.e., SI which does not necessitate intensive, restrictive services) which targets an established driver of SI, perceived burdensomeness toward others (PB). This R61/R33 proposal builds on pilot findings by first demonstrating the ability of the brief module to engage the target now in a rigorous randomized controlled trial (RCT; R61) and then evaluating the module embedded within a larger CBT protocol in preparation for a larger clinical trial (R33). We will measure the target using established and novel measures recently developed and validated by the MPIs with an eye toward establishing multimethod measurement of PB for a possible larger clinical trial. The proposed intervention module addresses current empirical and clinical gaps in the following ways: The intervention module (1) precisely targets a suicide-related interpersonal risk factor, leveraging the MPIs recent clinical trial findings and in congruence with a large body of work on suicide etiology and theory; (2) is easily combined with standard therapies via simplicity from a streamlined manual and intuitive concepts, (3) and is highly scalable via a cognitive-behavioral approach with high resource efficiency (e.g., minimal therapist training, little session time needed). The study is therefore congruent with NIMH Strategy 3.2.A: “Developing multi-modal intervention strategies that combine the simultaneous application of established or novel [psychosocial interventions] to selectively access specific therapeutic targets.”