Short-term associations between nonsuicidal and suicidal thoughts and behaviors: A daily diary study with high-risk adolescents

•Proximal links between self-injurious thoughts and behaviors are understudied.•Suicidal adolescent inpatients filled out daily surveys for a month post discharge.•Nonsuicidal self-injury (NSSI) and suicidal thoughts were associated at daily level.•Anti-suicide motive for NSSI engagement was frequently endorsed when NSSI occurred.•Youth with high NSSI levels were at higher suicidal behavior risk over this period. In this daily dairy study of adolescents at elevated suicide risk, we examined proximal associations between nonsuicidal self-injury (NSSI) and suicidal thoughts as well as behaviors. We also investigated the prominence of the anti-suicide function underlying NSSI engagement, relative to intrapersonal and interpersonal motives. Seventy-eight adolescents (67.9% female; ages 13-17) hospitalized due to suicide risk completed daily surveys assessing NSSI and suicidal thoughts for four weeks after discharge (n=1621 observations). Suicidal behavior (actual, aborted, interrupted suicide attempts) was assessed at 1-month follow-up. Over and above lifetime NSSI, adolescents who generally experienced more enduring (OR=2.54, p=