Investigating an Interoceptive Model of Adolescent Suicidal Thoughts and Behaviors

Suicide is the second leading cause of death among U.S. adolescents. Implicated in suicidal thoughts and behaviors (STBs) are difficulties in self-perception and understanding (SP/U), defined in the National Institute of Mental Health's Research Domain Criteria as a set of related abilities involving awareness of internal experiences and behavior, naming and disclosing emotions, and achieving a positive and coherent sense of self-identity. Suicide-related impairments in SP/U are theorized as stemming from or body-brain communication, and they may be specifically related to impaired heart-brain communication (cardiac interoception). The proposed multi-method study examines the cross-sectional and prospective relationship of heart-brain communication to adolescent STBs. Innovatively, we seek to establish biological roots of suicide-related SP/U impairment by directly examining heart-brain communication using state-of-the-art neurophysiological measures. Specific aims are to (Aim 1) replicate and extend our knowledge of the role of SP/U in adolescent STBs, (Aim 2) test the role of heart-brain communication in adolescent SP/U and STBs, and (Aim 3) examine the direct and moderating influences of family environments on relationships in Aims 1 and 2. Participants (N=65; ages 13-17) will be recruited from a well-characterized pool of clinically-referred adolescents. To ensure variability in STBs during the study period, all eligible participants will have a history of STBs, which is a robust predictor of future STBs. Participants will complete a baseline laboratory visit with clinical interviews and questionnaires, a behavioral heartbeat perception task, and recording of heartbeat-evoked brain potentials during a variety of relevant mental states, including responses to suicide-themed stimuli. At the baseline timepoint, participants would also complete a 5-day ecological momentary assessment (EMA) about their SP/U and STBs in daily life. Three and 6 months later, the adolescents would repeat questionnaires, EMA, and interview remotely (no in-person visit required). Family, caregiver, and dyadic observational data are amply available archivally and will be updated selectively. Teacher reports of adolescents' functioning will be collected to complement adolescent EMA reports of daily experiences in another relevant, real-world context. Our group has an exceptional track record of adolescent retention (>89%), collection of teacher reports (91%), and thorough completion of adolescent EMA prompts (>90%). The proposed study represents the first test of a novel, comprehensive, biopsychosocial model of heart-brain communication in adolescent STBs. Because this study leverages resources connected to an existing, well-characterized research sample of adolescents (R01 MH101088), it is highly achievable. The primary investigator has a demonstrated initial growth as a suicide researcher and commitment to future suicide prevention research. The dedicated and accomplished research team have relevant expertise and concrete plans to facilitate the primary investigator's transition to career independence. The specific isolated relationships hypothesized in our conceptual model have already been supported, including in preliminary analyses supporting this application. The proposed Young Investigator Grant would provide the applicant with critical skills in suicide research and yield initial findings on the promise of heart-brain communication as an innovative, biological, environmentally sensitive, mechanistic link in the causal chain ending in adolescent suicide.