Mental Illness and Violence: Proof or Stereotype?

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Appendix A: Annotated Bibliography cont'd

Studies based on Samples of Incarcerated Offenders cont'd

Feder, L. (1991). A comparison of the community adjustment of mentally ill offenders with those from the general prison population. Law and Human Behaviour, 15(5), 477-493.

Purpose and Objective: The purpose of this study was to compare the post-prison adjustment of mentally ill offenders and a comparable group of non-mentally ill offenders, and to examine the extent to which differences could be accounted for by mental illness.

Research Design: A prospective longitudinal design was used with an eighteen month post-prison follow-up.

Setting: New York, United States of America.

Study Subjects: Study subjects were 400 non-mentally ill offenders and 147 mentally ill offenders discharged from prison between July 30, 1982 and September 1, 1983.

Measures: Mentally ill offenders were defined as persons requiring psychiatric hospitalization during their incarceration. No information is provided on the diagnostic mix. Non-mentally ill offenders were those who did not require hospitalization. As the author points out, some comparison subjects could have been suffering from mental illnesses that either did not require hospitalization, or were not obvious to prison staff.

Main Findings: Mentally ill offenders were more likely than non-mentally ill offenders to have been arrested for a violent crime. Also, some differences existed between the groups with respect to other demographic and history variables.

During follow-up, 64% of mentally ill offenders and 60% of non-mentally ill offenders were re-arrested at least once. With respect to violent crimes, 19% of mentally ill offenders and 15% of non-mentally ill offenders were re-arrested. These differences were not statistically significant. Mentally ill offenders were re-arrested significantly less frequently for drug offenses.

Differences were noted between mentally ill offenders and non-mentally ill offenders with respect to the way in which arrests for non-violent crimes were handled: mentally ill offenders received a sentence involving prison time less frequently than did non-mentally ill offenders, and were channelled more often into the mental health system than their non-mentally ill counterparts. No differences were noted with respect to violent crimes, indicating that discretion among criminal justice personnel decreases in cases of serious offenses. When statistical techniques were used to control for groups differences in criminal history, the only significant factors distinguishing the groups in subsequent arrests were age and prior arrests. Psychiatric status was not significant.

Conclusions: With the exception of drug-related offenses which were lower among mentally ill offenders, psychiatric status did not explain variations in post-release arrests for violent or other types of crime. The major explanatory factors were younger age and prior arrests. However, together, these only accounted for 8% of the total variation indicating that there are many factors, other than the ones studies, that account for post-prison adjustment.

Methodological Critique: The problem with (1) classifying mentally ill offenders based on psychiatric hospitalization and (2) the resulting possibility that some of the comparison group may have been suffering from mental illness, may explain the lack of difference noted in subsequent community adjustment. This would be particularly problematic if a high proportion of comparison subjects were suffering from substance abuse disorders that would be unlikely to prompt a psychiatric admission, but which are shown in other studies to be associated with higher post-release criminality.

Causality: Because this study uses selected samples from institutionalized offender populations, results cannot be used to infer causality.

Gingell, C.R. (1991). The criminalization of the mentally ill: An examination of the hypothesis. Doctoral Dissertation. Burnaby, British Columbia: Simon Fraser University.

Purpose and Objective: To establish estimates of prevalence and to examine the value of the criminalization hypothesis.

Research Design: Cross-sectional design.

Setting: A local jail in Vancouver, British Columbia, Canada.

Study Subjects: A non-representative sample of 317 consecutive admissions from whom a “selected group” identified as having a “high probability of mental illness” was chosen for further study. A second group consisted of 107 inmates selected through a stratified random sample from the general prison population.

Measures: Brief Psychiatric Rating Scale and Diagnostic Interview Schedule (DIS) were used for only a  “selected group of inmates”.

Main Findings: High rates of prevalence of schizophrenia in both the first and second groups, with rates of 8% and 13% respectively.

Conclusions: Support was found for the criminalization hypothesis. A large number of mentally ill individuals, specially those suffering from major mental conditions, end up in prisons.

Methodological Critique: The use of DIS is considered inappropriate for this type of population given a circularity of symptoms and criminal offenses, some of the symptoms implying acts of violence. Futhermore, this study has methodological problems regarding the sampling strategy and the peculiar selection of subjects selected for the first group. This may have resulted in selection bias as well as subjective bias on the part of the researcher.

Causality: A causal inference cannot be made on the basis of these findings.

Grunberg, F., Klinger, B.I. and Grumet, B. (1977). Homicide and deinstitutionalization of the mentally ill. American Journal of Psychiatry, 134(6), 685-687.

Purpose and Objective: To examine if there has been a disproportionate increase of crimes committed by the mentally ill, and whether this is due to the shift from institutional to community-based care.

Research Design: Retrospective review of files.

Setting: Small county in New York State, United States of America.

Study Subjects: All 48 cases of homicides where offenders were either convicted or found not guilty by reason of insanity were identified from the county prosecutor files for the period January 1, 1963-December 31, 1975.

Measures: Cases were divided into four groups: guilty with or without previous psychiatric hospitalizations, and not guilty by reason of insanity with or without previous psychiatric hospitalizations. Data were collected for two periods: before 1969, the year the community psychiatric centre was established in the county; and after 1969.

Main Findings: The proportion of those found guilty and not previously mentally ill remained the same for the two periods, whereas those found not guilty by reason of insanity with previous hospitalizations increased six-fold.

Conclusions: Mental illness may be related to violence (homicide) and this may be related to policies of deinstitutionalization.

Methodological Critique: This is an interesting study because of the way in which the investigators operationalized their concepts. However, the small sample size of the study is problematic. In addition, mental illness was defined in very broad terms (not guilty by reason of insanity, or previous hospitalizations). Conversely, criminality was defined solely in terms of  homicide. Other factors that could have been related to the homicides were not considered.

Causality: A causal inference cannot be made on the basis of these findings.

Guze, S.B., Goodwin, D.W. and Crane, J.B. (1969). Criminality and psychiatric disorders. Archives of General Psychiatry, 20, 583-591.

Purpose and Objective: To determine the prevalence of psychiatric disorders and to measure the associations between mental illness and criminality.

Research Design: Longitudinal follow-up design.

Setting: Subjects were followed up over an eight- to nine-year period in various communities in the United States of America.

Study Subjects: The subjects were 223 convicted felons on parole, 94% of whom were located for follow-up.

Measures: Data were collected using structured diagnostic interviews with the study subjects and through interviews with their families. Criminality was defined as a felony conviction.

Main Findings: Sociopathy, drug dependency, and alcoholism were most frequently associated with criminality. Schizophrenia, affective disorders, and organic brain syndromes were not over-represented compared to the general population.

Conclusions: There is an increased risk of criminality for those patients suffering from alcohol dependency, sociopathy, or drug dependency.

Methodological Critique: Despite the massive efforts of this study, a number of major deficiencies were present including the diagnostic labels used, the type of instruments used, and the lack of control for other factors that could have been related to criminality. Subjects were selected for the sample on the basis of criminal activity and, therefore, positive associations may be more likely. Temporality between the diagnosis of mental illness and the crime was not clearly established with the result that the mental illness may have occurred subsequent to the criminality.

Causality: A causal inference cannot be made on the basis of these findings.

Hodgins, S. and Côté, G. (1993). The criminality of mentally disordered offenders. Criminal Justice and Behaviour, 20(2), 115-129.

Purpose and Objective: To address two hypotheses: (1) that mentally disordered inmates, compared to non-mentally disordered inmates, would have a history of more convictions and more convictions for violent offenses; and (2) among mentally disordered inmates, those with co-occurring antisocial personality disorder would have more total convictions and more convictions for violent offenses than those non-mentally disordered.

Research Design: The authors do not specify the design used, but data collection is consistent with a cross-sectional sample from which respondents were divided into two groups for comparison: mentally disordered inmates and non-mentally disordered.

Setting: A major Canadian federal penitentiary in Quebec (carceral institution holding inmates sentenced to serve over two years of time).

Study Subjects: A representative sample (461 subjects) taken from all male inmates (2,972) being held at the penitentiary on the date of survey (April 13, 1988). A total of 107 were mentally disordered and 349 were not.

Measures: Inmates were administered the Diagnostic Interview Schedule Version III-A. A sub-sample was re-examined by a different interviewer five weeks after with good interrater agreement (kappa = .78).

Main Findings: Mentally disordered inmates were not found to have a history of more convictions and more violent convictions than non-mentally disordered inmates. Among those with a mental disorder, those with a comorbid condition (a major mental disorder plus antisocial personality disorder) had more convictions, but no difference was found with respect to more violent convictions.

Methodological Critique: Findings from this study support the notion that mentally disordered offenders are not processed differently in the criminal justice system compared to non-mentally disordered offenders. However, it is not clear whether this relationship holds among non-institutionalized samples.

Causality: A causal inference cannot be made on the basis of these findings.

Hodgins, S. and Hébert, J. (1984). Une étude de rélance auprès de malades mentaux ayant commis des actes criminelles. Revue canadienne de psychiatrie, 29(8), 669-675.

Purpose and Objective: To follow persons found unfit or not guilty by reason of insanity to compare those placed in a maximum security psychiatric hospital with those placed in other mental hospitals or psychiatric units in general hospitals.

Research Design: A historical follow-up study with a follow-up period of seven to nine years.

Setting: A maximum security psychiatric hospital, six psychiatric hospitals, and thirteen general hospital psychiatric units in the Province of Quebec, Canada.

Study Subjects: Two hundred and seventy five subjects: (a) all those found unfit; and (b) all those found not guilty by reason of insanity over a period of three years (1973 to 1975).

Measures: Data were obtained from clinical records, Royal Canadian Mounted Police (RCMP) files, or the Commission d'Examen du Quebec.

Main Findings: Social disadvantage was a  common denominator among the groups. With the exception of the location where the crime was committed, the groups did not differ in important respects (e.g. destination after hospitalization, duration of outpatient treatment, and occupation). Thirty percent had been treated at the maximum security hospital. The majority of those who were violent, usually males, had been admitted to the maximum security hospital.

Conclusions: The majority of those found not guilty by reason of insanity suffered from schizophrenia. Further crimes during the follow-up period were committed by 27.5%: 25.9% among those from the maximum security hospital and 33.9% from the other institutions. Overall, community clinical follow-up and social opportunities for these patients were deficient.

Methodological Critique: This study provides excellent data describing patients' re-entry into the community. However, the study is marred by the usual problems of retrospective follow-ups including the need to rely on records assembled by many coders, diagnoses given by many unknown clinicians, and information provided by many different people. It is not clear what a priori theoretical rationale governed the researchers' choice of the two study groups. Also, the objectives of the study appear very broad and unfocused.

Causality: Because this project was designed to examine how these two groups of mental patients fared once released, not to test any associations, no statement can be made about any putative relationship between mental illness and violence.

Lamb, H.R. and Grant, R.W. (1982). The mentally ill in an urban county jail. Archives of General Psychiatry, 39, 17-22.

Purpose and Objective: To review patterns of mental illness, and type of criminal offense to test the “criminalization” theory.

Research Design: Cross-sectional design.

Setting: A county jail for men in a large metropolitan area in the United States of America.

Study Subjects: A random sample (102) taken from all those referred for a psychiatric evaluation to the forensic unit of the jail.

Measures: None mentioned, but subjects were examined by the authors using DSM-III criteria.

Main Findings: Ninety percent had prior psychiatric hospitalizations, and 92% had prior arrests. More than half were facing a felony charge of which 39% were facing a crime of violence. A large proportion (78%) had histories of serious physical violence. Psychiatric hospitalizations were recommended in 76% of the cases.

Conclusions: This population was characterized by extensive experience with the justice and mental health systems, severe acute and chronic mental illness, and poor functioning.

Methodological Critique: It is not clear how  the results of this study based on a highly selected sample of persons referred for forensic assessment could be used to test the criminalization thesis.

Causality: A causal inference cannot be made on the basis of these findings.

Lamb, H.R., Weinberger, L.E. and Gross, B.H. (1988). Court-mandated community outpatient treatment for persons found not guilty by reason of insanity: A five year follow-up. American Journal of Psychiatry, 145(4), 450-456.

Purpose and Objective: To study readjustment into the community of persons found not guilty by reason of insanity and referred to a community outpatient program.

Research Design: Prospective, longitudinal, follow-up for five years up to December 31, 1985.

Setting: Conditional Release Program of the Department of Health of Los Angeles, California, United States of America.

Study Subjects: Seventy-nine subjects found not guilty by reason of insanity from July 1, 1979 to December 31, 1980 and who were referred to community supervision and treatment.

Measures: Readjustment was measured in terms of re-arrest, hospitalization, and revocation rates.

Main Findings: During the follow-up period, 32% were rearrested (72% on crimes of violence), 47% were hospitalized, and 48% of those on conditional release were revoked.

Conclusions: This population needs social controls and long-term treatment while in the community.

Methodological Critique: Although the authors were careful with the general parameters of the follow-up study, the sample was obviously highly selected for both serious violent crime and mental illness. Although a large proportion was re-arrested for crimes of violence, the authors do not provide other reasons for re-arrest or revocation, so it is not known what proportion of these cases were re-arrested or revocated for minor crimes.

Causality: Due to the selection biases and the lack of control for potential confounding factors, this study cannot be used to make a statement on the matter of causality between mental illness and criminality.

Larkin, E., Murtagh, S. and Jones, S. (1988). A preliminary study of violent incidents in a Special Hospital (Rampton). British Journal of Psychiatry, 153, 226-231.

Purpose and Objective: The purpose of the study was: (1) to study the nature, type, location, times, severity, and object of all violent incidents in the wards of a maximum security unit in the United Kingdom; and (2) to compare findings with data from similar studies in general hospitals.

Research Design: A six-month prospective study of all violent incidents.

Setting: A maximum security unit  specifically set up by law for patients “subject to detention who require treatment under conditions of special security on account of their dangerous, violent or criminal propensities”.

Study Subjects: All violent incidents (N=1144) that occurred during the six months of the study (rather than violent individuals) were the main focus of study.

Measures: Data were collected using a special questionnaire designed for this purpose. Violence was defined as causing injury or damaging property.

Main Findings: Eleven hundred and forty four incidents reported (reporting rate of 60% in female wards and 80% in male rooms). Females comprised 25% of the total population, but represented 75% of the total number of incidents. Nursing staff were three times more likely to be the target of assaults.

Conclusions: As expected, violent incidents occurred more frequently in the Special Hospital, were more serious in nature, and resulted in greater injury.

Methodological Critique: This is a good prospective study on the issue of violence in inpatient units, in this case a secure unit. By definition, though, these units take the most seriously and violent of mental patients, and those who had already been adjudicated as criminal. Hence, the sample is highly selected with individuals who are both criminal and mentally ill. The study, although prospective, does not make any statement in relation to diagnosis, or to correlation between illness and type of violence.

Causality: A causal inference cannot be made on the basis of these findings.

Lindqvist, P. (1986). Criminal homicide in Northern Sweden 1970-1981: Alcohol intoxication, alcohol abuse and mental illness. International Journal of Law and Psychiatry, 8, 19-37.

Purpose and Objective: To review cases of homicide and determine the frequency of alcohol intoxication and mental illness among victimizers, and to compare alcohol-related homicides to sober homicides.

Research Design: Review of records.

Setting: A small, sparsely populated area of Sweden.

Study Subjects: All homicide offenders in the area during the study period (64 with 71 victims), January 1, 1970 to December 31, 1980.

Measures: Data were collected from files.

Main Findings: The homicide rate was estimated to be 0.7%. Mutual intoxication (both victim and victimizer) was found in 44% of the cases. The majority of victims were related to the offenders. Sixty-three percent of offenders had had previous psychiatric care. Alcohol abuse was prevalent (30%) among the sample; an additional 27% were mentally ill. Nineteen offenders were sober with no previous criminal record.

Conclusions: Alcohol is an important factor in homicides.

Methodological Critique: The major problem with this study is the method of ascertainment of alcohol use at the time of the offense. This was sometimes determined by information from third parties rather than by alcoholemia (level of alcohol in the blood). No information is given about the quality of the information contained in the records so it is unclear to what extent cases of alcoholism or mental illness could have been under-reported. In addition, it is not clear how soon offenders were arrested after the offense, thus it is impossible to ascertain the association between alcohol consumption and the offense.

Causality: A causal inference cannot be made on the basis of these findings.

Martell, D.A. and Dietz, P.E. (1992). Mentally disordered offenders who push or attempt to push victims onto the subway tracks in New York City. Archives of General Psychiatry, 49, 472-475.

Purpose and Objective: This study was undertaken in order to shed light on the characteristics of persons who push victims onto subway tracks.

Research Design: A descriptive review of a case series of files.

Setting: New York State Office of Mental Health, New York City, United States of America.

Study Subjects: Data were available on twenty of the 26 subjects.

Measures: Data were abstracted from files using a structured protocol.

Main Findings: All but one (19, 95%) of the subjects were mentally ill at the time of the offense and had a history of psychiatric admission (71% for schizophrenia). Sixty-five percent were homeless.

Conclusions: Homelessness and mental illness appear to be important factors in this type of crime.

Methodological Critique: This is an interesting study but suffers from a very small and selected study group and the lack of a comparison group.

Causality: A causal inference cannot be made on the basis of these findings.

McKnight, C.K., Mohr, J.W., Quinsey, R.E., and Erochko, J. (1966). Mental illness and homicide. Canadian Psychiatric Association Journal, 11(3), 91-98.

Purpose and Objective: To study demographic, criminological, and clinical characteristics of homicide offenders.

Research Design: A retrospective review of records.

Setting: A maximum security hospital in the Province of Ontario, Canada.

Study Subjects: One hundred cases of homicide directly referred from the courts over a period  spanning 30 years.

Measures: Information was obtained from the clinical records.

Main Findings: The majority of subjects (81%) were charged with murder as opposed to manslaughter. Twenty-seven percent were not guilty by reason of insanity. Fifty-seven percent were diagnosed as suffering from schizophrenia and of these, 40% from paranoid schizophrenia. Peak ages at the time of offense were from 30 to 35 years.

Conclusions: The authors conclude that the most serious crime of murder seems to be most commonly committed by schizophrenic patients.

Methodological Critique: There is no special strength to this study. It consisted of a review of records spanning a long period of time, among a population which by definition has been adjudicated criminal and mentally ill, at the most severe level for both. The sample was highly selected, no standardization of instruments was used, and no comment was provied on the quality of data, which is usually very poor in old records. The authors' conclusions go well beyond the data provided by this very descriptive study.

Causality: A causal inference cannot be made on the basis of these findings.

McMain, S., Webster, C.D. and Menzies, R.J. (1989). The post-assessment careers of mentally disordered offenders. International Journal of Law and Psychiatry, 12, 189-201.

Purpose and Objective: This study was a preliminary attempt to monitor the institutional careers and post-discharge functioning of mentally disordered offenders over a long period of time.

Research Design: Prospective follow-up of a cohort formed by individuals discharged after a forensic assessment.

Setting: Community follow-up of patients discharged from hospitals in Toronto, Ontario, Canada.

Study Subjects: Two hundred patients discharged in 1979 from a forensic service in Toronto were followed for six years.

Measures: Information was gathered from mental hospitals and correctional records.

Main Findings: Ninety-two percent of the cohort incurred a period of incarceration or hospitalization during the follow-up period, and a majority experienced repetitive cycles of institutionalization with decreasing frequency as the follow-up period progressed. Only 8% were able to avoid hospitalization or reincarceration.

Conclusions: It is possible that forensic inpatient assessment may be related to the repetitive cycles of further institutionalization in the years following discharge.

Methodological Critique: This is a preliminary report that deals with the adjustment of forensically assessed mental patients in the community. Given the absence of a control group of persons who did not  undergo a forensic assessment, the conclusions made by the authors go beyond the scope of the data provided.

Causality: A causal inference cannot be made on the basis of these findings.

Menzies, R.J. and Webster, C.D.(1987). Where they go and what they do: The longitudinal careers of forensic patients in the medicolegal complex. Canadian Journal of Criminology, 29, 275-293.

Purpose and Objective: To map the post-assessment careers of forensically assessed mental patients.

Research Design: Longitudinal, prospective cohort study with a two-year follow-up period.

Setting: Community, mental hospitals around Metropolitan Toronto in Canada.

Study Subjects: A cohort of 571 subjects discharged from a forensic assessment unit in Toronto in 1978.

Measures: Data were abstracted from records from hospitals and correctional agencies.

Main Findings: One quarter of the cohort were repetitively reincarcerated or rehospitalized, 36% were reincarcerated but not rehospitalized, and 25% were rehospitalized but not reincarcerated. Repetitive forensic assessments were experienced by 24.4% of the sample. One-third of the cohort showed assaultive behaviour during the follow-up period, over half of these while in the community.

Conclusions: There is a system problem in forensic remands that may be related to the cyclicity of remands and reinstitutionalizations.

Methodological Critique: A strength of this study is the prospective follow-up of this group of patients. However, a control group was not included, and, therefore, the authors cannot offer evidence to support the claim that there may be a system problem fostering cyclicity of remands and reinstutionalizations. No consideration was given to the alternate hypothesis that reinstutionaliztions were due to recurring mental problems.

Causality: A causal inference cannot be made on the basis of these findings.

Nestor, P.G. (1992). Neuropsychological and clinical correlates of murder and other forms of extreme violence in a forensic psychiatric population. The Journal of Nervous and Mental Disease, 180(7), 418-423.

Purpose and Objective: To examine the relationship between neuropsychological impairment and severe violence.

Research Design: Retrospective review of records.

Setting: A maximum security psychiatric hospital. Location not specified.

Study Subjects: Forty patients referred for neuropsychological evaluation between the years 1987 and  1989. These subjects were divided into two groups: the young group (N=22) below age 25 (mean age 19.3 years), and the old group (N=18) above 25 (mean age 41.4 years).

Measures: DSM-III-R diagnosis had been recorded on all the subjects, and subjects had been administered the Wechsler Adult Intelligence Scale-Revised (WAIS-R) as a measure of various aspects of intelligence, the Wide Range Achievement Tests for oral reading, written spelling and arithmetic, and the Trail Making Test (Part B). Police records were also reviewed.

Main Findings: The two groups did not differ significantly in history of drug use. The older group had more diagnoses of psychosis and more hospitalizations. The young group had more learning disabilities and a larger history of court involvement.

Conclusions: Neuropsychological and clinical profiles differed between the two groups, but both groups had a history of substance abuse. Older offenders were more likely to have acted alone and to have victimized a relative.

Methodological Critique: This was a review of records whose quality of diagnosis is not described. In addition, the neuropsychological examination appears superficial. The sample is obviously highly selected, and confounding factors such as socioeconomic status, were not considered.

Causality: A causal inference cannot be made on the basis of these findings.

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