An Investigation into the Impact of ‘Guilty But Mentally Ill' Verdicts on Capital Murder Sentencing

This research investigates whether an empirical basis exists for arguing that defendants with serious mental impairments should be excluded from the death penalty. By examining rates of death-sentencing in cases involving Guilty but Mentally Ill adjudications and verdicts, this research seeks to answer three primary questions: First, does evidence of mental impairment decrease the likelihood of a death sentence? Second, if so, are there any particular types of impairment that appear more likely to decrease the chances of a death sentence? Third, have these patterns changed over time? While these questions emerged in response to United States Supreme Court decisions excluding certain categories of people, including individuals with mental retardation, from the death penalty, it also bears on the substantial literature regarding the stigmatization and perceived dangerousness of people with mental illness.