Insanity has long been viewed as an excuse rather than a justification; insane people are acquitted not because they did nothing wrong, but because they are considered morally blameless for their wrongful conduct. The research compared a new substantive test based on justificatory rather than exculpatory principles (a quasisubjective justification (QSJ) test) to Finkel's relative culpability test and to two excuse-oriented tests, American Law Institute (ALI) test and the Federal test adopted in 1984 (IDRA). The participants were 171 college students, who were randomly assigned one of eight booklets, incorporating the seven cases and one of the four insanity tests in either the culpable or nonculpable condition. Results revealed that QSJ and Finkel's test both produced significant verdict differences, whereas ALI and IDRA verdicts were not significantly different. However, the QSJ effect was observed only in cases judged low in justification and thus did not have a determinative role across cases; other variables, such as the perceived severity of the disorder and the culpability for brining about the disorder, to which only Finkel's test was sensitive, seemed to have more explanatory power. Tables and 44 references (Author abstract modified)