- Email: [email protected]
The predictors of insanity acquittal
/ntematbne/ Joumel 01Law and Psychiatry. Vol. 13.217-224. Printed m the U.S.A. All rights resewed.
1990
0160-2527/90 83.00 + 00 Copyright % 1990 Pergamon Press plc
The Predictors of Insanity Acquittal Marnie E. Rice* and Grant T. Harris*
Introduction The issue of which persons charged with criminal offenses should be acquitted because of mental disorder has been the subject of considerable debate (American Psychiatric Association, 1983; Perr, 1985). The debate has taken many forms. One issue has to do with which of several tests of insanity ought to be employed (e.g., Milliken, 1985). For example, the M’Naghten rule differs from American Law Institute (ALI) test in that, according to the former, those who are insane do not “know” what they are doing or that it is wrong while the latter substitutes the apparently more liberal concept of “appreciation.” In addition, the AL1 test does not require total lack of appreciation, only the “lack of substantial capacity,” and the AL1 test permits an “irrestible impulse” criterion (APA, 1983). Some investigators have shown that large changes to the legislatively determined test of insanity result in few changes to the characteristics of those found insane compared to those who are convicted (Packer, 1985; Pasewark, Randolph, & Bieber, 1985; Stokman & Heiber, 1984). There is general agreement that the proportion of all accused persons who are subsequently acquitted on grounds of insanity is exceedingly small, probably under 1% (Pasewark, 1981; Pasewark & McGinley, 1985). Indeed, the proportion of criminal charges resulting in a verdict of not guilty by reason of insanity is very small even among those persons sent for a pretrial psychiatric examination (Daniel, Beck, Herath, Schmitz, & Menninger, 1984; Menzies, 1987). An important question about the issue of insanity pertains to which characteristics are central to a determination of insanity. Debates over the precise definitions of such terms as “appreciating the nature and quality of an act” and “disease of the mind” are probably irrelevant if it can be shown that different and relatively objectively-determined characteristics of the offense and the accused can account for virtually all of the variability in verdict. Because the issue of insanity is considered in so few cases, it is important to address the question of comparison groups. Others have shown that pretrial psychiatric assessments are rare, that among such evaluatees the question of insanity is rarely raised in court and that a minority of those who plead insanity are so found (Menzies, 1987; Pasewark, 1981). In order to examine variables related to the determination of insanity, then, several comparison groups with whom to contrast the *Mental Health Centre, Penetanguishene, Ontario, Canada, LOK 1PO. This research was supported by Ontario Ministry of Health Grant 01677. The authors wish to thank Vern Quinsey for helpful comments on an earlier version. 217
218
MARNIE E. RICE and GRANT T. HARRIS
insanity acquittees are possible. These include a random group of offenders, a group of offenders for whom the insanity plea was unsuccessfully pleaded in court, a random group of evaluatees who were not subsequently found insane, and a group of evaluatees not subsequently found insane who were also matched to the group of insanity acquittees on index offense. There have been some U. S. studies in which insanity acquittees have been compared with one or more of the comparison groups listed above. Despite jurisdictional differences, and differences in the choice of comparison groups, studies have consistently found that insanity acquittees are more likely to be diagnosed as psychotic or schizophrenic (Packer, 1987; Pasewark, Jeffrey, & Bieber, 1987; Steadman, Keitner, Braff, & Arvanites, 1983) than comparison subjects, and have had more extensive prior psychiatric histories (Pasewark et al., 1987; Steadman et al., 1983; Stokman & Heiber, 1984). There is also some support for the notion that insanity acquittees have committed more serious offenses than other offenders (Stokman & Heiber, 1984). Findings have been inconsistent with regard to age, relationship between victim and offender, and previous criminal history (Boehnert, 1987; Packer, 1987; Pasewark et al., 1987; Pasewark, Pantle, & Steadman, 1979; Steadman et al., 1983; Stokman & Heiber, 1984). In a related study, persons given a pretrial forensic assessment were divided into those for whom the psychiatric recommendation favored the insanity defense and those for whom the recommendation was against insanity (Daniel et al., 1984). It was found that persons for whom the insanity defense was recommended were more likely to exhibit psychotic symptoms than persons for whom the recommendation was against insanity. The role of psychiatric testimony in the verdict of insanity has received very little attention in research studies to date (Pasewark, 1986). However, there is some evidence that a court verdict of insanity is very highly related to an opinion in favor of insanity from a pretrial forensic examination (Quinsey & Maguire, 1983; Rogers, Seman, & Stampley, 1984; Steadman et al., 1983). The first purpose of the present study was to provide controlled Canadian data on the characteristics of insanity acquittees. Comparison subjects included a random group of evaluatees, and a group of evaluatees matched to the insanity acquittees on index offense. The second goal was to examine the roles of psychiatric testimony, and the characteristics of the accused and the offense in the determination of the verdict of insanity. Method
Setting and Subjects The study was conducted at a Canadian maximum security psychiatric institution. At the time of the study, the institution annually admitted an average of approximately 140 male patients each year from the courts for a psychiatric evaluation. The issues addressed during the forensic assessment were fitness to stand trial, future dangerousness, suitability for bail, and most importantly for this study, the applicability of a defense of insanity. During the period of the study, these psychiatric evaluations were conducted by multidisciplinary teams comprising psychiatrists, psychologists, case historians, and nursing staff. The
THE PREDICTORS
OF INSANITY ACQUITTAL
219
evaluations consisted of the compilation of detailed psychosocial histories based upon the patients’ own reports, police reports, interviews with patients’ families, and information from the patients’ previous institutionalizations. In each case, the assessment ended with a letter from the psychiatrist to the court. In many cases, the psychiatrist, and less frequently a psychologist, also testified at the accused’s trial. The subjects of this study comprised three groups. The insanity acquittees were all patients (n = 53) who were admitted to the institution over a three year period and who were eventually found not guilty by reason of insanity (NGRI) for the criminal charges that were the basis of the admission. The first comparison group (called the random group) were a random sample of 42 patients admitted for pretrial evaluation during the same period who were not found NGRI. Although not a requirement for inclusion, each of these individuals was eventually convicted of charges stemming from the offense which had led to his admission. The second comparison group (called the matched group) were 53 patients who were admitted for pretrial assessment during the same three year period. For each subject in the NGRI group, a subject was randomly selected for the matched group from those non-NGRIs charged with the same offense. Procedure
Using the detailed file information compiled during each patient’s stay, research assistants not affiliated with the multidisciplinary assessment team coded several variables from the clinical records. Diagnosis, for example, was not necessarily determined by the forensic psychiatrist, but was made by the research assistants applying DSMIII criteria to the information on file. In fact, substantially more subjects (an additional 10% in the NGRI group, for example) received a hospital diagnosis of psychosis but did not meet the DSMIII criteria for a psychotic disorder. These records have formed the basis for several previous studies (e.g., Quinsey & Maguire, 1983, 1986). Interrater reliabilities were evaluated by having two raters independently code each variable on a sample of 20 subjects (some of whom were actually subjects in a different study). All variables met a minimum reliability criterion of .70 (Pearson r) for continuous variables or .70 (kappa) for categorical variables, and the mean reliabilites were .90 and .87, respectively. Although most of the study variables shown in Table 1 are self-explanatory, a few require fuller description. “Index offense” refers to the offense with which the patient had been formally charged at the time of his admission. “Family socioeconomic status” was rated on an 8-point scale that ranged from “unemployed or on welfare” to “employed as a high level professional requiring a postgraduate degree. ” “Prior criminal history (property),” “prior criminal history (violent), ” “prior criminal history (total),” and “offense seriousness” were all evaluated using a system developed by Akman and Normandeau (1967). “Physical attractiveness” was rated from photographs on file using a seven-point scale. “Strength of prosecution’s case” was the total points obtained on a scale on which one point was assigned for each eye witness, a confession to police, each piece of hard physical evidence (blood type match, fingerprints, etc.), the accused being found in possession of an article belonging to a victim, the accused
220
MARNIE E. RICE and GRANT T HARRIS
Characteristics
TABLE 1 of NGRI, Random, and Matched Subject Groups
Group Variable Index offense: (O/O) Murder Manslaughter Criminal Negligence Causing Death Attempted Murder Wounding Assault Causing Bodily Harm Common Assault Rape Indecent Assault Arson Robbery Weapons Offenses Property Offenses Age at offense Highest grade completed Prior psychiatric admissions Months in psychiatric hospital Prior criminal charges Family socioeconomic status Prior criminal history (property) Prior criminal history (violent) Prior criminal history (total) Offense seriousness Physical attractiveness Strenght of prosecution’s case Witnesses for NGRI Witnesses against NGRI Attended college (O/O) Employed at arrest (O/O) Alcohol involved index offense (O/o) Ever married (O/O) Living alone at arrest (o/o) Schizophrenic (o/o) Psychotic (O/o) Personality Disorder (o/o)
NGRI
Random
Matched
40
2
43
0
5
0
2 34 8 2 0 2 4 9 0 0 0 32.7 9.38 2.77 15.6 4.58 4.00 3.43 3.40 6.83 20.9 3.73 4.19
1.22 1.57 26 30 32 42 38 66 75 13
0
0
5
32
0
0
24
8
14
2
5
2
10
4
0
9
10
0
10
0
17 26.6 9.57 5.55 20.5 8.40 3.97 8.50 6.48 14.98 10.6 3.98 3.71 2 1.04 17 44 32 26 27 38 41 46
~2 or F
72.1 ***
0 30.7 8.83 1.98 13.8 8.42 3.67 9.00 9.81 18.81 21.7 3.25 3.87 2 1.12 13 50 60 43 23 9 13 65
8.41 * n.s. 3.49 n.s. 4.65’, 4.16’ ns. 5.39’, 5.09’ ns. 6.08’, 5.24’ 9.40” 4.20 n.s. 3.53, 3.37 10.4”, 7.36” 2.91 4.37’ 7.43’ ns. ns. 7.36”, 36.8”’ 11.2”“, 42.7*” 12.7”‘,29.9*” l
l
Note. Numbers under the heading ,$ or F are ~2s for categorical variables (i.e., those with % beside them) and Fs for continuous variable (all other variables). Degrees of freedom = 1 for all ~2s except for index offense where df = 13. Degrees of freedom > 1,93 for all continuous variables except for witnesses for NGRI and witnesses against NGRI, where df > 1,31.x2 or Fvalues shown refer to the comparison between the NGRI group and the comaprison group corresponding to the underlined value for that variable. Where two values are shown, both comparisons were significant or marginally significant and the first value refers to the comparison between the NGRI and random groups, and the second to the comparison between the NGRI and matched group. Where no asterisks are shown beside the For ~2 value, the comparison was significant at the .lO level. < ,001. ‘p < .05., “p < .Ol., “‘p
THE PREDICTORS
OF INSANITY ACQUITTAL
221
being found in possession of a weapon linked to the offense, the accused having no corroborated alibi, a similarity of the offense to the established modus operandi of the accused, and the accused being identified by the victim after the offense. Finally, “witnesses for and against the NGRI” were the number of forensic experts (psychiatrists or psychologists) who testified on behalf of the defense or the prosecution during the trial of the accused. Results and Discussion The main characteristics of each of the three groups and the primary results of the study are shown in Table 1. Also shown are statistically significant differences among the groups. As can be seen in Table 1, insanity acquittees had been charged with more serious offenses than the randomly chosen convicted offenders. Also, insanity acquittees were older, had less extensive criminal histories, were more likely to be psychotic (mostly schizophrenic), and less likely to be personality disordered. Interestingly, more witnesses testified both in support of and against a verdict of insanity in the trials of the insanity acquittees than in the trials of the randomly chosen convicted offenders. This suggests that expert testimony in favor of the verdict was not the most important factor in determining who would be found insane or convicted. Earlier work at the same institution showed that verdict and psychiatric evidence were correlated (Quinsey & Maguire, 1983), but, of course, such a correlation cannot establish that the verdicts were the result of the evidence. The present data suggest that testimony and verdict are both determined by other factors. Finally, the insanity acquittees had less extensive psychiatric histories than the randomly chosen convicted subjects. Although this is different from the findings of other studies, the other studies that have investigated psychiatric history have used either persons who pleaded insanity in court but were unsuccessful (Pasewark et al., 1987; Steadman et al., 1983) or a group of convicted offenders, the great majority of whom would not have had a pretrial psychiatric evaluation (Stokman & Heiber, 1984). When the insanity acquittees were matched to convicted subjects charged with similar offenses, other interesting differences emerged. This comparison also showed that insanity acquittees had less extensive criminal histories and more witnesses both for and against the insanity verdict. The matched convicts showed even larger differences in diagnosis than the randomly,chosen comparison subjects. In addition, insanity acquittees were more physically attractive and were more likely to have attended college but less likely to be employed. Compared to the convicted subjects matched on index offense, insanity acquittees were less likely to have been drunk at the time of the index offense. Another important goal of this study was to examine the question of how few characteristics could be used to discriminate between groups. Thus, the data were subjected to multivariate analyses. The first analyses sought to discriminate between the NGRI and random evaluatee groups using multiple discriminant analyses. These analyses showed that, by far, the most important discriminating variable was index offense. In fact, the addition of all other study variables to a dichotomization of index offense (murder/attempt murder or not) only yielded a nonsignificant increase in multiple R from .664 to .676. In
222
MARNIE E. RICE and GRANT T. HARRIS
evaluating the accuracy with which cases could be assigned to group based upon combinations of study variables, it was shown that no combination of variables could improve upon this use of a simple dichotomization of index offense (murder or attempted murder versus not). Simply predicting that all evaluatees charged with murder or attempted murder would be found NGRI and that all those charged with any other offense would be convicted yielded a correct classification rate of 82 % . Using such a simple rule meant that only 3 convicted subjects and 14 insanity acquittees were misclassified, for a Relative Improvement over Chance or RIOC (Loeber & Stouthamer-Loeber, 1987) of 84%, p < .OOOl. Clearly, index charge was such a large component to insanity decisions that it was important to see how groups could be discriminated when index charge was controlled. Thus, the next analyses sought to discriminate between the NGRI and matched groups. As can be seen in Table 1, the most important discriminating variable was DSMIII diagnosis. A dichotomization of diagnosis (psychotic or not) was correlated .630 with the criterion variable (group), and the addition of all other study variables increased multiple R to .716. Similar to the result reported above, no combination of study variables yielded a significant improvement over the use of a dichotomization of diagnosis-psychotic (schizophrenia, major affective disorder, dementia) or not-in predicting which subjects would be found insane. With offense controlled, simply saying that psychotic subjects would be found insane and all others convicted yielded a correct classification rate of 81% such that 13 acquittees and 7 convicted subjects were misclassified (RIOC = 71%) p < .OOOl). Clearly, the most important determinants of insanity verdicts in this study were index offense seriousness and diagnosis. Although offense seriousness is not part of any definition of insanity, it is, in fact, a crucial factor because, regardless of legal definitions, few people involved in the judicial process (including judges, prosecutors, defense attorneys, police, mental health professionals) see value in subjecting mentally ill persons charged with minor offenses to the indeterminate disposition and hospitalization that typically follow a verdict of insanity in many jurisdictions (Quinsey, 1981). Support for this conclusion comes from a study in Michigan that showed that verdicts of not guilty by reason of insanity for minor offenses greatly increased after a court decision that ended mandatory incarceration for insanity acquittees (Packer, 1985). In addition, the randomly selected group of evaluatees in the current study actually had more extensive psychiatric histories than the NGRI subjects. It is likely that these random comparison subjects were seen as candidates for a psychiatric remand because of their psychiatric histories but were not regarded as insane because their charges tended to be minor or because they were not psychotic. This is of interest because legal criteria in Canada do not restrict insanity to psychoses, even though forensic experts often mistakenly think they do (Rogers, Turner, Helfield, & Dickens, 1988), and as mentioned above, offense seriousness is irrelevant to the legal definition of insanity. The present results show that most decisions regarding insanity can be modelled simply by saying that insanity acquittees are those persons accused of murder or attempted murder who show clear evidence of psychosis (almost always schizophrenia) during a post-offense psychiatric examination. Others
THE PREDICTORS
OF INSANITY
ACQUITTAL
223
have shown that what little variance remains may be attributed to such variables as personal interests of judges and the numbers of forensic psychiatrists in the local community (Pasewark et al., 1979; Stokman & Heiber, 1984). These results all lend considerable support to the contention that debates about the subtleties of the wording of definitions of insanity are of little practical significance (e.g., Milliken, 1985). In Canada, the law pertaining to insanity states that “No person shall be convicted of an offense, while he . . . has disease of the mind to an extent that renders him incapable of appreciating the nature and quality of an act or omission or of knowing that an act or omission is wrong” (Heather, 1986). The present results show that in terms of how the law is in fact applied, a fair approximation might be, “No person shall be convicted after having committed homicide (or attempted homicide) if he is found to be psychotic shortly afterwards.” References Akman, D. D., & Normandeau, A. (1967). The measurement of crime and delinquency in Canada: A replication study. British Journal of Criminology, 7, 129-149. American Psychiatric Association (1983). American Psychiatric Association statement on the insanity defense. The American Journal of Psychiafry, 140, 681-687. Boehnert, C. E. (1987). Characteristics of those evaluated for insanity. Journal of Psychiatry and Law, I5, 229-246. Daniel, A. E., Beck, N. C., Hemath, A., Schmitz, M., & Menninger, K. (1984). Factors correlated with psychiatric recommendations of incompetency and insanity. The Journal of Psychiarry and Low, 12, 527544. Heather, D. R. H. (1986). Snow’s Annotated Criminal Code. Toronto: Carswell. Loeber, R., & Southamer-Loeber, M. (1987). Prediction. In H. C. Quay, (Ed.), Handbook of juvenile delinquency (pp. 325-382). New York: Wiley. Menzies, R. J. (1987). Cycles of control: the transcarceral careers of forensic patients. Inrernarional Journal of Law and Psychiarry, 10,233-249. Milliken, A. D. (1985). The insanity defence. Canadian Journal of Psychiatry, 30, 323-328. Packer, 1. K. (1985). Insanity acquittals in Michigan 1969-1983: The effects of legislative and judicial changes. The Journal of Psychiatry and Law, 13,419-434. Packer, I. K. (1987). Homicide and the insanity defense: A comparison of sane and insane murderers. Behavioral Sciences and the Law, 5, 25-35. Pasewark, R. A. (1981). Insanity plea: A review of the research literature. The Journal of Psychiarry and Law, 9, 357-401. Pasewark, R. A. (1986). A review of research on the insanity defense. Anna/s of the American Academy of Political and Social Science, 484, 1OO-114. Pasewark, R. A., Jeffrey, R., & Bieber, S. (1987). Differentiating successful and unsuccessful insanity plea defendants in Colorado. The Journd of Psychiarry and Low, 9, 55-71. Pasewark, R. A., & McGinley, H. (1985). Insanity plea: National’survey of frequency and success. The Journal of Psychiatry and Law, 13, 101-108. Pasewark, R. A., Pantle. M. L., & Steadman, H. J. (1979). Characteristics and disposition of persons found not guilty by reason of insanity in New York state. American Journal of Psychiatry, 136.655-660. Pasewark, R. A., Randolph, R. L., & Bieber, S. (1985). Insanity plea: Statutory language and trial procedures. The Journal of Psychiatry and Low, 13, 399-422. Perr, I. N. (1985). The insanity defense: The case for abolition. Hospiral and Community Psychiatry, 36, 5154. Quinsey, V. L. (1981). The long term management of the mentally disordered offender. In S. J. Hucker, C. D. Webster, & M. Ben-Aron (Eds.) Mental disorder and criminal responsibility, (pp. 137-155). Toronto: Butterworths. Quinsey, V. L., & Maguire, A. (1983). Offenders remanded for a psychiatric examination: Perceived treatability and disposition. International Journal of Luw and Psychiatry 6, 193-205.
224
MARNIE E. RICE and GRANT T. HARRIS
Quinsey, V. L., & Maguire, A. (1986). Actuarial and clinical prediction of dangerousness concerning maximum security psychiatric patients. Journal of Inferpersonol Violence, I, 143-171. Rogers, R., Seman, W., & Stampley, J. (1984). A study of socio-demographic characteristics of individuals evaluated for insanity. International Journal of Offender Therapy and Comparative Criminology, 28, 3-
10. Rogers, R., Turner, R. E., Helfield, R., & Dickens, S. (1988). Forensic psychiatrists’ and psychologists’ understanding of insanity: Misguided expertise? Cunodian Journal of Psychiatry, 33, 691-695. Steadman, H. J., Keitner, L., Braff, J., & Arvanites, M. A. (1983). Factors associated with a successful insanity plea. American Journal of Psychiutry, 140, 401-405. Stokman, C. L. J., & Heiber, P. G. (1984). The insanity defense reform act in New York state, 1980-1983.
International Journal of Law and Psychiatry, 7, 367-384.
1990
0160-2527/90 83.00 + 00 Copyright % 1990 Pergamon Press plc
The Predictors of Insanity Acquittal Marnie E. Rice* and Grant T. Harris*
Introduction The issue of which persons charged with criminal offenses should be acquitted because of mental disorder has been the subject of considerable debate (American Psychiatric Association, 1983; Perr, 1985). The debate has taken many forms. One issue has to do with which of several tests of insanity ought to be employed (e.g., Milliken, 1985). For example, the M’Naghten rule differs from American Law Institute (ALI) test in that, according to the former, those who are insane do not “know” what they are doing or that it is wrong while the latter substitutes the apparently more liberal concept of “appreciation.” In addition, the AL1 test does not require total lack of appreciation, only the “lack of substantial capacity,” and the AL1 test permits an “irrestible impulse” criterion (APA, 1983). Some investigators have shown that large changes to the legislatively determined test of insanity result in few changes to the characteristics of those found insane compared to those who are convicted (Packer, 1985; Pasewark, Randolph, & Bieber, 1985; Stokman & Heiber, 1984). There is general agreement that the proportion of all accused persons who are subsequently acquitted on grounds of insanity is exceedingly small, probably under 1% (Pasewark, 1981; Pasewark & McGinley, 1985). Indeed, the proportion of criminal charges resulting in a verdict of not guilty by reason of insanity is very small even among those persons sent for a pretrial psychiatric examination (Daniel, Beck, Herath, Schmitz, & Menninger, 1984; Menzies, 1987). An important question about the issue of insanity pertains to which characteristics are central to a determination of insanity. Debates over the precise definitions of such terms as “appreciating the nature and quality of an act” and “disease of the mind” are probably irrelevant if it can be shown that different and relatively objectively-determined characteristics of the offense and the accused can account for virtually all of the variability in verdict. Because the issue of insanity is considered in so few cases, it is important to address the question of comparison groups. Others have shown that pretrial psychiatric assessments are rare, that among such evaluatees the question of insanity is rarely raised in court and that a minority of those who plead insanity are so found (Menzies, 1987; Pasewark, 1981). In order to examine variables related to the determination of insanity, then, several comparison groups with whom to contrast the *Mental Health Centre, Penetanguishene, Ontario, Canada, LOK 1PO. This research was supported by Ontario Ministry of Health Grant 01677. The authors wish to thank Vern Quinsey for helpful comments on an earlier version. 217
218
MARNIE E. RICE and GRANT T. HARRIS
insanity acquittees are possible. These include a random group of offenders, a group of offenders for whom the insanity plea was unsuccessfully pleaded in court, a random group of evaluatees who were not subsequently found insane, and a group of evaluatees not subsequently found insane who were also matched to the group of insanity acquittees on index offense. There have been some U. S. studies in which insanity acquittees have been compared with one or more of the comparison groups listed above. Despite jurisdictional differences, and differences in the choice of comparison groups, studies have consistently found that insanity acquittees are more likely to be diagnosed as psychotic or schizophrenic (Packer, 1987; Pasewark, Jeffrey, & Bieber, 1987; Steadman, Keitner, Braff, & Arvanites, 1983) than comparison subjects, and have had more extensive prior psychiatric histories (Pasewark et al., 1987; Steadman et al., 1983; Stokman & Heiber, 1984). There is also some support for the notion that insanity acquittees have committed more serious offenses than other offenders (Stokman & Heiber, 1984). Findings have been inconsistent with regard to age, relationship between victim and offender, and previous criminal history (Boehnert, 1987; Packer, 1987; Pasewark et al., 1987; Pasewark, Pantle, & Steadman, 1979; Steadman et al., 1983; Stokman & Heiber, 1984). In a related study, persons given a pretrial forensic assessment were divided into those for whom the psychiatric recommendation favored the insanity defense and those for whom the recommendation was against insanity (Daniel et al., 1984). It was found that persons for whom the insanity defense was recommended were more likely to exhibit psychotic symptoms than persons for whom the recommendation was against insanity. The role of psychiatric testimony in the verdict of insanity has received very little attention in research studies to date (Pasewark, 1986). However, there is some evidence that a court verdict of insanity is very highly related to an opinion in favor of insanity from a pretrial forensic examination (Quinsey & Maguire, 1983; Rogers, Seman, & Stampley, 1984; Steadman et al., 1983). The first purpose of the present study was to provide controlled Canadian data on the characteristics of insanity acquittees. Comparison subjects included a random group of evaluatees, and a group of evaluatees matched to the insanity acquittees on index offense. The second goal was to examine the roles of psychiatric testimony, and the characteristics of the accused and the offense in the determination of the verdict of insanity. Method
Setting and Subjects The study was conducted at a Canadian maximum security psychiatric institution. At the time of the study, the institution annually admitted an average of approximately 140 male patients each year from the courts for a psychiatric evaluation. The issues addressed during the forensic assessment were fitness to stand trial, future dangerousness, suitability for bail, and most importantly for this study, the applicability of a defense of insanity. During the period of the study, these psychiatric evaluations were conducted by multidisciplinary teams comprising psychiatrists, psychologists, case historians, and nursing staff. The
THE PREDICTORS
OF INSANITY ACQUITTAL
219
evaluations consisted of the compilation of detailed psychosocial histories based upon the patients’ own reports, police reports, interviews with patients’ families, and information from the patients’ previous institutionalizations. In each case, the assessment ended with a letter from the psychiatrist to the court. In many cases, the psychiatrist, and less frequently a psychologist, also testified at the accused’s trial. The subjects of this study comprised three groups. The insanity acquittees were all patients (n = 53) who were admitted to the institution over a three year period and who were eventually found not guilty by reason of insanity (NGRI) for the criminal charges that were the basis of the admission. The first comparison group (called the random group) were a random sample of 42 patients admitted for pretrial evaluation during the same period who were not found NGRI. Although not a requirement for inclusion, each of these individuals was eventually convicted of charges stemming from the offense which had led to his admission. The second comparison group (called the matched group) were 53 patients who were admitted for pretrial assessment during the same three year period. For each subject in the NGRI group, a subject was randomly selected for the matched group from those non-NGRIs charged with the same offense. Procedure
Using the detailed file information compiled during each patient’s stay, research assistants not affiliated with the multidisciplinary assessment team coded several variables from the clinical records. Diagnosis, for example, was not necessarily determined by the forensic psychiatrist, but was made by the research assistants applying DSMIII criteria to the information on file. In fact, substantially more subjects (an additional 10% in the NGRI group, for example) received a hospital diagnosis of psychosis but did not meet the DSMIII criteria for a psychotic disorder. These records have formed the basis for several previous studies (e.g., Quinsey & Maguire, 1983, 1986). Interrater reliabilities were evaluated by having two raters independently code each variable on a sample of 20 subjects (some of whom were actually subjects in a different study). All variables met a minimum reliability criterion of .70 (Pearson r) for continuous variables or .70 (kappa) for categorical variables, and the mean reliabilites were .90 and .87, respectively. Although most of the study variables shown in Table 1 are self-explanatory, a few require fuller description. “Index offense” refers to the offense with which the patient had been formally charged at the time of his admission. “Family socioeconomic status” was rated on an 8-point scale that ranged from “unemployed or on welfare” to “employed as a high level professional requiring a postgraduate degree. ” “Prior criminal history (property),” “prior criminal history (violent), ” “prior criminal history (total),” and “offense seriousness” were all evaluated using a system developed by Akman and Normandeau (1967). “Physical attractiveness” was rated from photographs on file using a seven-point scale. “Strength of prosecution’s case” was the total points obtained on a scale on which one point was assigned for each eye witness, a confession to police, each piece of hard physical evidence (blood type match, fingerprints, etc.), the accused being found in possession of an article belonging to a victim, the accused
220
MARNIE E. RICE and GRANT T HARRIS
Characteristics
TABLE 1 of NGRI, Random, and Matched Subject Groups
Group Variable Index offense: (O/O) Murder Manslaughter Criminal Negligence Causing Death Attempted Murder Wounding Assault Causing Bodily Harm Common Assault Rape Indecent Assault Arson Robbery Weapons Offenses Property Offenses Age at offense Highest grade completed Prior psychiatric admissions Months in psychiatric hospital Prior criminal charges Family socioeconomic status Prior criminal history (property) Prior criminal history (violent) Prior criminal history (total) Offense seriousness Physical attractiveness Strenght of prosecution’s case Witnesses for NGRI Witnesses against NGRI Attended college (O/O) Employed at arrest (O/O) Alcohol involved index offense (O/o) Ever married (O/O) Living alone at arrest (o/o) Schizophrenic (o/o) Psychotic (O/o) Personality Disorder (o/o)
NGRI
Random
Matched
40
2
43
0
5
0
2 34 8 2 0 2 4 9 0 0 0 32.7 9.38 2.77 15.6 4.58 4.00 3.43 3.40 6.83 20.9 3.73 4.19
1.22 1.57 26 30 32 42 38 66 75 13
0
0
5
32
0
0
24
8
14
2
5
2
10
4
0
9
10
0
10
0
17 26.6 9.57 5.55 20.5 8.40 3.97 8.50 6.48 14.98 10.6 3.98 3.71 2 1.04 17 44 32 26 27 38 41 46
~2 or F
72.1 ***
0 30.7 8.83 1.98 13.8 8.42 3.67 9.00 9.81 18.81 21.7 3.25 3.87 2 1.12 13 50 60 43 23 9 13 65
8.41 * n.s. 3.49 n.s. 4.65’, 4.16’ ns. 5.39’, 5.09’ ns. 6.08’, 5.24’ 9.40” 4.20 n.s. 3.53, 3.37 10.4”, 7.36” 2.91 4.37’ 7.43’ ns. ns. 7.36”, 36.8”’ 11.2”“, 42.7*” 12.7”‘,29.9*” l
l
Note. Numbers under the heading ,$ or F are ~2s for categorical variables (i.e., those with % beside them) and Fs for continuous variable (all other variables). Degrees of freedom = 1 for all ~2s except for index offense where df = 13. Degrees of freedom > 1,93 for all continuous variables except for witnesses for NGRI and witnesses against NGRI, where df > 1,31.x2 or Fvalues shown refer to the comparison between the NGRI group and the comaprison group corresponding to the underlined value for that variable. Where two values are shown, both comparisons were significant or marginally significant and the first value refers to the comparison between the NGRI and random groups, and the second to the comparison between the NGRI and matched group. Where no asterisks are shown beside the For ~2 value, the comparison was significant at the .lO level. < ,001. ‘p < .05., “p < .Ol., “‘p
THE PREDICTORS
OF INSANITY ACQUITTAL
221
being found in possession of a weapon linked to the offense, the accused having no corroborated alibi, a similarity of the offense to the established modus operandi of the accused, and the accused being identified by the victim after the offense. Finally, “witnesses for and against the NGRI” were the number of forensic experts (psychiatrists or psychologists) who testified on behalf of the defense or the prosecution during the trial of the accused. Results and Discussion The main characteristics of each of the three groups and the primary results of the study are shown in Table 1. Also shown are statistically significant differences among the groups. As can be seen in Table 1, insanity acquittees had been charged with more serious offenses than the randomly chosen convicted offenders. Also, insanity acquittees were older, had less extensive criminal histories, were more likely to be psychotic (mostly schizophrenic), and less likely to be personality disordered. Interestingly, more witnesses testified both in support of and against a verdict of insanity in the trials of the insanity acquittees than in the trials of the randomly chosen convicted offenders. This suggests that expert testimony in favor of the verdict was not the most important factor in determining who would be found insane or convicted. Earlier work at the same institution showed that verdict and psychiatric evidence were correlated (Quinsey & Maguire, 1983), but, of course, such a correlation cannot establish that the verdicts were the result of the evidence. The present data suggest that testimony and verdict are both determined by other factors. Finally, the insanity acquittees had less extensive psychiatric histories than the randomly chosen convicted subjects. Although this is different from the findings of other studies, the other studies that have investigated psychiatric history have used either persons who pleaded insanity in court but were unsuccessful (Pasewark et al., 1987; Steadman et al., 1983) or a group of convicted offenders, the great majority of whom would not have had a pretrial psychiatric evaluation (Stokman & Heiber, 1984). When the insanity acquittees were matched to convicted subjects charged with similar offenses, other interesting differences emerged. This comparison also showed that insanity acquittees had less extensive criminal histories and more witnesses both for and against the insanity verdict. The matched convicts showed even larger differences in diagnosis than the randomly,chosen comparison subjects. In addition, insanity acquittees were more physically attractive and were more likely to have attended college but less likely to be employed. Compared to the convicted subjects matched on index offense, insanity acquittees were less likely to have been drunk at the time of the index offense. Another important goal of this study was to examine the question of how few characteristics could be used to discriminate between groups. Thus, the data were subjected to multivariate analyses. The first analyses sought to discriminate between the NGRI and random evaluatee groups using multiple discriminant analyses. These analyses showed that, by far, the most important discriminating variable was index offense. In fact, the addition of all other study variables to a dichotomization of index offense (murder/attempt murder or not) only yielded a nonsignificant increase in multiple R from .664 to .676. In
222
MARNIE E. RICE and GRANT T. HARRIS
evaluating the accuracy with which cases could be assigned to group based upon combinations of study variables, it was shown that no combination of variables could improve upon this use of a simple dichotomization of index offense (murder or attempted murder versus not). Simply predicting that all evaluatees charged with murder or attempted murder would be found NGRI and that all those charged with any other offense would be convicted yielded a correct classification rate of 82 % . Using such a simple rule meant that only 3 convicted subjects and 14 insanity acquittees were misclassified, for a Relative Improvement over Chance or RIOC (Loeber & Stouthamer-Loeber, 1987) of 84%, p < .OOOl. Clearly, index charge was such a large component to insanity decisions that it was important to see how groups could be discriminated when index charge was controlled. Thus, the next analyses sought to discriminate between the NGRI and matched groups. As can be seen in Table 1, the most important discriminating variable was DSMIII diagnosis. A dichotomization of diagnosis (psychotic or not) was correlated .630 with the criterion variable (group), and the addition of all other study variables increased multiple R to .716. Similar to the result reported above, no combination of study variables yielded a significant improvement over the use of a dichotomization of diagnosis-psychotic (schizophrenia, major affective disorder, dementia) or not-in predicting which subjects would be found insane. With offense controlled, simply saying that psychotic subjects would be found insane and all others convicted yielded a correct classification rate of 81% such that 13 acquittees and 7 convicted subjects were misclassified (RIOC = 71%) p < .OOOl). Clearly, the most important determinants of insanity verdicts in this study were index offense seriousness and diagnosis. Although offense seriousness is not part of any definition of insanity, it is, in fact, a crucial factor because, regardless of legal definitions, few people involved in the judicial process (including judges, prosecutors, defense attorneys, police, mental health professionals) see value in subjecting mentally ill persons charged with minor offenses to the indeterminate disposition and hospitalization that typically follow a verdict of insanity in many jurisdictions (Quinsey, 1981). Support for this conclusion comes from a study in Michigan that showed that verdicts of not guilty by reason of insanity for minor offenses greatly increased after a court decision that ended mandatory incarceration for insanity acquittees (Packer, 1985). In addition, the randomly selected group of evaluatees in the current study actually had more extensive psychiatric histories than the NGRI subjects. It is likely that these random comparison subjects were seen as candidates for a psychiatric remand because of their psychiatric histories but were not regarded as insane because their charges tended to be minor or because they were not psychotic. This is of interest because legal criteria in Canada do not restrict insanity to psychoses, even though forensic experts often mistakenly think they do (Rogers, Turner, Helfield, & Dickens, 1988), and as mentioned above, offense seriousness is irrelevant to the legal definition of insanity. The present results show that most decisions regarding insanity can be modelled simply by saying that insanity acquittees are those persons accused of murder or attempted murder who show clear evidence of psychosis (almost always schizophrenia) during a post-offense psychiatric examination. Others
THE PREDICTORS
OF INSANITY
ACQUITTAL
223
have shown that what little variance remains may be attributed to such variables as personal interests of judges and the numbers of forensic psychiatrists in the local community (Pasewark et al., 1979; Stokman & Heiber, 1984). These results all lend considerable support to the contention that debates about the subtleties of the wording of definitions of insanity are of little practical significance (e.g., Milliken, 1985). In Canada, the law pertaining to insanity states that “No person shall be convicted of an offense, while he . . . has disease of the mind to an extent that renders him incapable of appreciating the nature and quality of an act or omission or of knowing that an act or omission is wrong” (Heather, 1986). The present results show that in terms of how the law is in fact applied, a fair approximation might be, “No person shall be convicted after having committed homicide (or attempted homicide) if he is found to be psychotic shortly afterwards.” References Akman, D. D., & Normandeau, A. (1967). The measurement of crime and delinquency in Canada: A replication study. British Journal of Criminology, 7, 129-149. American Psychiatric Association (1983). American Psychiatric Association statement on the insanity defense. The American Journal of Psychiafry, 140, 681-687. Boehnert, C. E. (1987). Characteristics of those evaluated for insanity. Journal of Psychiatry and Law, I5, 229-246. Daniel, A. E., Beck, N. C., Hemath, A., Schmitz, M., & Menninger, K. (1984). Factors correlated with psychiatric recommendations of incompetency and insanity. The Journal of Psychiarry and Low, 12, 527544. Heather, D. R. H. (1986). Snow’s Annotated Criminal Code. Toronto: Carswell. Loeber, R., & Southamer-Loeber, M. (1987). Prediction. In H. C. Quay, (Ed.), Handbook of juvenile delinquency (pp. 325-382). New York: Wiley. Menzies, R. J. (1987). Cycles of control: the transcarceral careers of forensic patients. Inrernarional Journal of Law and Psychiarry, 10,233-249. Milliken, A. D. (1985). The insanity defence. Canadian Journal of Psychiatry, 30, 323-328. Packer, 1. K. (1985). Insanity acquittals in Michigan 1969-1983: The effects of legislative and judicial changes. The Journal of Psychiatry and Law, 13,419-434. Packer, I. K. (1987). Homicide and the insanity defense: A comparison of sane and insane murderers. Behavioral Sciences and the Law, 5, 25-35. Pasewark, R. A. (1981). Insanity plea: A review of the research literature. The Journal of Psychiarry and Law, 9, 357-401. Pasewark, R. A. (1986). A review of research on the insanity defense. Anna/s of the American Academy of Political and Social Science, 484, 1OO-114. Pasewark, R. A., Jeffrey, R., & Bieber, S. (1987). Differentiating successful and unsuccessful insanity plea defendants in Colorado. The Journd of Psychiarry and Low, 9, 55-71. Pasewark, R. A., & McGinley, H. (1985). Insanity plea: National’survey of frequency and success. The Journal of Psychiatry and Law, 13, 101-108. Pasewark, R. A., Pantle. M. L., & Steadman, H. J. (1979). Characteristics and disposition of persons found not guilty by reason of insanity in New York state. American Journal of Psychiatry, 136.655-660. Pasewark, R. A., Randolph, R. L., & Bieber, S. (1985). Insanity plea: Statutory language and trial procedures. The Journal of Psychiatry and Low, 13, 399-422. Perr, I. N. (1985). The insanity defense: The case for abolition. Hospiral and Community Psychiatry, 36, 5154. Quinsey, V. L. (1981). The long term management of the mentally disordered offender. In S. J. Hucker, C. D. Webster, & M. Ben-Aron (Eds.) Mental disorder and criminal responsibility, (pp. 137-155). Toronto: Butterworths. Quinsey, V. L., & Maguire, A. (1983). Offenders remanded for a psychiatric examination: Perceived treatability and disposition. International Journal of Luw and Psychiatry 6, 193-205.
224
MARNIE E. RICE and GRANT T. HARRIS
Quinsey, V. L., & Maguire, A. (1986). Actuarial and clinical prediction of dangerousness concerning maximum security psychiatric patients. Journal of Inferpersonol Violence, I, 143-171. Rogers, R., Seman, W., & Stampley, J. (1984). A study of socio-demographic characteristics of individuals evaluated for insanity. International Journal of Offender Therapy and Comparative Criminology, 28, 3-
10. Rogers, R., Turner, R. E., Helfield, R., & Dickens, S. (1988). Forensic psychiatrists’ and psychologists’ understanding of insanity: Misguided expertise? Cunodian Journal of Psychiatry, 33, 691-695. Steadman, H. J., Keitner, L., Braff, J., & Arvanites, M. A. (1983). Factors associated with a successful insanity plea. American Journal of Psychiutry, 140, 401-405. Stokman, C. L. J., & Heiber, P. G. (1984). The insanity defense reform act in New York state, 1980-1983.
International Journal of Law and Psychiatry, 7, 367-384.