Of 102 counties, 27 has GBMI convictions between 1982 and 1984. Its use consistently increased during this period, although not guilty by reason of insanity (NGRI) cases did not decrease. Survey responses indicate that a majority feel the insanity defense has been abused, believed the GBMI statute would reduce the number of NGRI cases, and felt it would make it easier to prosecute cases but would not resolve the problem of proving intent. A majority believed that individuals found GBMI would receive mental health services, that there would be no change in the use of expert witnesses, and that neither jurors nor psychiatrists can distinguish mental illness from insanity. Finally, prosecutors found GBMI most useful in the plea negotiation process because it permits the offender to feel less responsible for the crime. 17 references.