Therapeutic evaluative conditioning to reduce adolescents' self-injurious thoughts and behaviors during and after psychiatric inpatient hospitalization. - Project Summary/Abstract Suicide is the 2nd leading cause of death for adolescents in the U.S. and non-lethal self- injurious thoughts and behaviors (SITB; e.g., suicide thoughts and attempts and non-suicidal self-injury (NSSI)) are each associated with the risk of future suicide. Many adolescents at high risk of suicide require psychiatric inpatient hospitalization. Unfortunately, these adolescents often continue to think about suicide and engage in NSSI while they are hospitalized. Most alarmingly, the month following hospitalization is the highest risk time for suicide, with the suicide rate 10 times higher than the general adolescent rate. Research suggests that people who engage in SITB show reduced implicit aversion toward SITB-related stimuli. This reduced aversion may facilitate SITB because it means this natural barrier preventing people from harming themselves is lower. People who engage in SITB also show increased implicit self- aversion, which may also facilitate SITB by supporting beliefs that one deserves to be punished. An intervention that reverses these potential facilitators of SITB may help prevent such thoughts and behaviors. The goal of the current project is to test one such intervention: Therapeutic Evaluative Conditioning (TEC), which aims to reduce SITB by increasing implicit aversion toward SITB and reducing implicit aversion toward oneself. TEC uses evaluative condition, a form of Pavlovian conditioning, in which, for example, SITB-related stimuli are paired with naturally aversive stimuli (e.g., snakes) to increase implicit aversion towards SITB. In studies among adults, TEC was associated with a 21-77% reduction in SITB over a month. The current project aims to test whether TEC can reduce SITB among self-injurious adolescents (1) during psychiatric inpatient hospitalization and (2) in the highest-risk period for suicide; the month after hospital discharge. First, a pilot study will test whether TEC is feasible and acceptable as an intervention for adolescents, both during and after inpatient hospitalization. Second, a randomized controlled trial will compare an active form of TEC with an inactive, control form of TEC. TEC has the potential to make broad impact reducing suicide because it is scalable, brief (> 5 min to complete), low-burden, and easy to administer via mobile app on a smartphone. Furthermore, in the post-discharge period, TEC can provide continuous therapeutic coverage, filling the gap between discharge and patients’ first outpatient therapy session. It can also be used to extend coverage in places where there are fewer resources for mental health care (e.g., rural areas). This proposal addresses the urgent need to reduce adolescent suicide, one of the most devastating and widespread public health problems in the U.S. and around the world.