Alcohol and marijuana use as daily predictors of suicide ideation and attempts among adolescents prior to psychiatric hospitalization

•Likelihood of suicide attempts increase on days when an adolescent uses alcohol.•Likelihood of suicide attempts increase on days when an adolescent uses marijuana.•Likelihood of suicide ideation does not increase on days when an adolescent uses alcohol.•Likelihood of suicide ideation increases on days when an adolescent uses marijuana.•Sexual minority youth are at elevated risk for suicide ideation. Little research has been conducted on alcohol use, marijuana use, and suicide ideation and attempts on a daily level, and specifically among adolescents prior to inpatient hospitalization. The purpose of this study was to examine the within (over time) and between (between adolescents) effects of alcohol use and marijuana use on suicide ideation and attempts. Participants included 50 adolescents (80% female; Mage = 15.8). All participants reported drinking alcohol in the prior three months and were receiving treatment in an inpatient psychiatric hospital. Random and mixed-effect models were used to test study hypotheses. Results from the random effect model indicated that alcohol use, marijuana use, hospitalization and sexual orientation were significant predictors of suicide attempts. Results from the mixed-effect model indicated that marijuana use, hospitalization, and sexual orientation were significant predictors of suicide ideation. Study findings extend current knowledge about the longitudinal and day-to-day relationship between alcohol and marijuana use and suicide ideation and attempts. Results underscore the importance of addressing alcohol and marijuana use in interventions with suicidal adolescents, recognizing that sexual minority youth may be at elevated risk for suicide ideation.