This study investigated the written responses of 314 students (grades 9 & 11) who were assigned 1 of 4 vignettes about a troubled peer. Each vignette represented a condition that was either high or low on diffusion of responsibility & high or low on ambiguity. Findings are presented & discussed. The authors believe that inducing youth to take responsible action in response to troubled peers may be one of the most important interventions for the prevention of adolescent suicidal behavior.