We seek to understand why young people think about and attempt suicide in a way that can inform assessment, treatment, and prevention of suicide risk. Our program of research has three broad goals: 1) to study the link between different forms of repetitive thinking, hopelessness, and suicidal ideation; 2) to understand what young people actually think about when they think about suicide, the form that these thoughts take, and whether there are subtypes of suicidal thoughts that can be used to predict who is likely to make a future suicide attempt; 3) to understand the interplay between culture and cognition in explaining risk for suicidal ideation and attempts; and 4) to identify laboratory-based methods of shifting the hopelessness-related cognitions that give rise to suicidal ideation.