The Guilty But Mentally Ill Verdict: Assessing the Impact of Informing Jurors of Verdict Consequences

In response to public opposition to the insanity defense, the Guilty But Mentally Ill(GBMI) verdict was enacted with the intention of limiting the number of insanity acquittals and alleviating the public’s concerns. Prior research suggests, however, that many jurors are making verdict decisions with limited knowledge of the dispositional consequences of the GBMI and NGRI verdicts. Further, jurors may erroneously assume that the GBMI verdict is a compromise between a NGRI and guilty verdict, which mitigates punishment. In reality, the dispositional consequences of a GBMI verdict are equivalent to or more restrictive than a guilty verdict. The current study examined the impact of informing jurors of the dispositional consequences of the GBMI and NGRI verdicts. In addition, it explores whether mock jurors’ attitudes toward the insanity defense, individuals with mental illness, and perceptions of the defendant’s dangerousness strengthens or attenuates the impact of informing mock jurors of dispositional consequences. Participants (N = 488) read a case summary of an apparently mentally ill male defendant charged with first-degree murder. Half of the participants were informed of the dispositional consequences of GBMI and NGRI verdicts, while the other half of participants received no such information. Then, they were asked to choose individual verdicts and complete a questionnaire that assessed attitudes toward the insanity defense, attitudes toward individuals with mental illness, and perceptions of the defendant’s dangerousness. Results indicate that informing participants of dispositional consequences of the GBMI and NGRI verdicts increases the likelihood that the NGRI verdict is selected over the GBMI verdict. In addition, participants who had more favorable attitudes toward the insanity defense and perceived the defendant as less dangerous selected the NGRI verdict over the GBMI verdict at an even higher rate when they were informed of dispositional consequences. The implications for educating jurors in trials that include the GBMI verdict option are discussed