This study extended the research on D. Schotte and G. Clum's (1982, 1987) theory of suicidal behavior by using structural equation modeling involving latent variables to evaluate whether the construct of hopelessness mediates between the constructs of problem-solving appraisal and suicide ideation. Participants in the study were 217 individuals in an intensive outpatient program targeting suicidal behavior in young adults. The results indicated a significant direct effect for hopelessness in predicting suicidal ideation. Consistent with the mediational hypothesis, the results also indicated a significant indirect effect for problem-solving appraisal (through its impact on hopelessness) in predicting suicidal ideation. The results not only replicate but also extend previous research by testing theory and increase the field's conceptualization of suicide ideation and behavior.