Am J Psychiatry 1989; 146:357-360
Copyright © 1989 by American Psychiatric Association
Maintenance of an insanity defense under Montana's "abolition" of the insanity defense
HJ Steadman, LA Callahan, PC Robbins and JP Morrissey
Policy Research Associates, Delmar, N.Y. 12054.
In 1979, Montana's insanity defense was replaced with the more restrictive
mens rea defense, a change that has been described as an example of
"abolition" of the insanity defense. The authors identified cases in which
mental health was an issue in seven Montana counties for 3 years before and
3 years after the 1979 reform. They found that acquittals based on the
insanity plea markedly declined, but that dismissals based on incompetence
to stand trial increased substantially following the reform. They conclude
that dismissal based on incompetence to stand trial became a substitute for
acquittal based on the insanity plea under mens rea.
