Revisiting the insanity defense: contested or consensus?

Abstract

The author assesses the accuracy of both the public's opinion and researchers' conclusions regarding the method of adjudication of insanity cases and investigates the impact of the various types of reforms enacted in the 1980s on the degree to which insanity cases are contested. Data from seven states are analyzed. The public's view that insanity cases are typically resolved by a jury trial is inaccurate. Only 14.4 percent of the 7,299 insanity cases involved a jury trial. Likewise, scholars' views that most cases are resolved through plea-bargained insanity acquittals are inaccurate. Only 42.9 percent of all insanity cases are plea bargains, and 87.9 percent of all plea bargains are to a conviction. Jury trials are most likely to occur when the case involves a violent crime such as murder and the defendant has not been diagnosed with a major mental illness. Public fears that defendants easily "fool" juries into an inappropriate insanity acquittal are also unfounded. Only 16.1 percent of all jury trials result in an insanity acquittal. In three states, the figure is 10 percent or less. Contrary to the conclusions drawn by some scholars, this author finds that several types of reforms enacted in the 1980s affected the processing of insanity cases.