Evaluating Michigan’s Guilty but Mentally Ill Verdict: An Empirical Study

Because Michigan’s GBMI statute has been in effect for several years, enough data exists to assess the statute’s use and practical effect. The purpose of this Project is to evaluate the statute and thus provide guidance for those legislatures considering similar proposals. This Project concludes that the new verdict has completely failed in its intended purpose. Part I describes the statute’s history, legislative purpose, and procedural mechanics. Part II analyzes the displacing effect of the GBMI verdict on other verdicts, and sets forth empirical data on the disparate characteristics of defendants who raise the insanity defense and are subsequently found GBMI, NGRI, or guilty. Part III analyzes the data and concludes that the statute has failed to achieve its goals. No fewer defendants are being found NGRI today than before the GBMI statute was enacted. Although the strong influence of Michigan’s Center for Forensic Psychiatry in insanity-related defenses is one reason to believe that the GBMI verdict may have a different effect in other states, in Michigan it is clear that the statute has merely substituted a new name tag for certain defendants who, in the absence of the new statute, probably would have been found guilty.