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Measuring the Effects of the Guilty But Mentally Ill (GBMI) Verdict

NCJ Number
140470
Journal
Law and Human Behavior Volume: 16 Issue: 4 Dated: (August 1992) Pages: 447- 462
Author(s)
L A Callahan; M A McGreevy; C Cirincione; H J Steadman
Date Published
1992
Length
16 pages
Annotation
The effects of guilty but mentally ill (GBMI) legislation on the use of the insanity defense in Georgia were studied using data on all defendants entering an insanity plea before (1976-1981) and after (1982-1985) the introduction of the GBMI verdict.
Abstract
Data were collected in 12 Georgia counties on all persons who were indicted for a felony and pled not guilty by reason of insanity (NGRI) from 1976 through 1985. The final sample included 2,553 subjects. The analysis focused on whether the enactment of a GBMI statute affected the volume and rate of NGRI pleas and acquittals, whether the GBMI statute affected the characteristics of those raising the plea and those acquitted NGRI, how those found GBMI compared to those acquitted NGRI or found guilty, and how confinement careers of NGRI's and GBMI's compared to those found guilty. In contrast to earlier studies, results indicated that GBMI decreased the likelihood of an insanity verdict and affected the composition of those found NGRI. Defendants pleading insanity and found GBMI were typically white males with a serious mental disorder and charged with murder or robbery in which an unrelated female victim was involved. Data also indicated that defendants who pleaded insanity and were found GBMI received harsher sentences than their guilty counterparts. The authors conclude that the GBMI verdict will make the insanity plea a less appealing option for mentally ill defendants. 41 references, 4 tables, and 3 figures