Mental Illness and Violence: Proof or Stereotype?

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Appendix A: Annotated Bibliography cont'd

Other Empirical Studies of Interest

The following empirical studies raise key methodological points that have implications for drawing causal inferences as identified in the “Comment” sections that appear at the end of each of the following structured abstracts.

Cirincione, C., Steadman, H.J., Robbins, P.C. and Monahan, J. (1994). Mental illness as a factor in criminality: A study of prisoners and mental patients. Criminal Behaviour and Mental Health, 4, 33-47.

Purpose and Objectives: To compare long-term patterns of crime among mentally disordered offenders and prison inmates. The main hypothesis under investigation was that criminological variables would be the best predictors of subsequent criminality.

Research Design: Research presented is based on subjects previously studied and reported on in 1984. A historical cohort study design was used with a follow-up period of eleven years.

Setting: New York State, United States of America.

Study Subjects: Subjects were identified from admission records of males under the age of 65 years admitted to New York State mental health facilities and prisons in 1968 and 1978. Study subjects comprised four cohorts: prisoners with no history of mental illness; prisoners with a history of mental illness; patients with previous arrests; and patients with no previous arrests.

Measures: Data describing subsequent arrests and hospitalizations were collected from archival sources.

Main Findings: In general, the 1978 cohorts showed higher arrest rates compared to the 1968 cohorts. With respect to subsequent arrests, prisoners in each era without previous hospitalizations were the most prone to re-arrest and patients with no arrest history were the least  likely. The hybrid groups had similar, intermediate levels of arrest, falling in between the other two groups. Similar patterns were noted for violent crimes. Mental patients with no prior arrests were somewhat less likely to be arrested than the general population.

Conclusions: Arrest history is a stronger predictor of subsequent crime than is a history of state mental hospitalization. Prisoners with no prior hospitalizations pose the greatest threat of subsequent violence and criminality.

Comment: This study confirms the importance of controlling for arrest history when assessing the relationship between mental hospitalization and criminality—something which few studies have taken into consideration.

Harry, B. (1985). Violence and official diagnostic nomenclature. Bulletin of the American Academy of Psychiatry and the Law, 13(4), 385-388.

Purpose and Objective: To assess the degree to which the belief in the positive association between mental illness and violence has been accepted.

Research Design: Content analysis of DSM psychiatric nomenclature used between 1952 and 1980.

Measures: The proportion of disorders with descriptive words or diagnostic criteria that contain references to violence in the various versions of official psychiatric nomenclature (DSM-I, DSM-II, and DSM-III). Violence was defined as including both violence to self and violence toward others.

Main Findings: Less than 3% of disorders in DSM-I and DSM-II contained words or criteria indicating violent behaviour. This jumped to 46.6% in DSM-III. Considering only diagnostic criteria, 26.2% of disorders in DSM-III contained words relating to violence. The diagnostic groups with the largest number of violent disorders included substance use disorders, organic mental disorders, affective disorders, and disorders occurring during childhood.

Conclusions: The percentages of mental disorders officially described or defined in terms of violent acts has increased, blurring the boundary between mental illness and violence and confounding any relationship between the two.

Comment: This study has important methodological implications for the apparent increasing finding of an association between mental disorders and violence that has appeared in the recent literature (e.g. last 15 years), but not prior to that time. Furthermore, it calls into question the ability of researchers to define mental illness independently of violence for the purposes of study, particularly when using DSM-III (or presumably subsequent) nosological systems.

Harry, B. and Steadman, H.J. (1988). Arrest rates of patients treated at a community mental health center. Hospital and Community Psychiatry, 39(8), 862-866.

Purpose and Objective: The purposes of this  study were to: (a) ascertain the arrest rates of inpatients, outpatients, and emergency patients after their first known contact for treatment at a community mental health centre; and (b) determine if the predictors of arrest among state hospital populations, reported in the literature, are the same for community mental health populations.

Research Design: A historical cohort design with a variable follow-up depending on the study entry date. Subjects were followed through to October 1984 giving an average of nine years of follow-up for the 1975 cohort and one year of follow-up for the 1983 cohort.

Setting: A comprehensive community mental health centre in a small city in Missouri, United States of America.

Study Subjects: Study subjects were randomly selected from the records of all adult patients admitted to the centre in 1975 and 1983, where their admission was their first known psychiatric contact. First psychiatric contacts were identified by noting patients' self-reports and by checking statewide records for previous contacts with other state-supported mental health facilities. A total of 200 inpatient, 181 outpatient, and 186 emergency first admissions occurred during 1983 only. Census data were used for the local ten county catchment area to calculate population values.

Measures: Data on social and clinical factors were abstracted from the health records. Diagnoses reflected DSM-III terminology. State-wide adult criminal arrest records were obtained for each subject through to October 1984. Violent crimes were considered to be homicide, assault, and child battering. Potentially violent crimes were robbery and weapons violations. Sexual crimes were rape, sodomy, and sexual abuse.

Main Findings: Findings reported in this paper were incorrect. Corrections appear in a subsequent Letter to the Editor [Harry, 1989, Hospital and Community Psychiatry, 40(12), 1303. The corrected findings are presented below. The fundamental conclusions of the paper were unchanged by these corrections.

One-year arrest rates per 1,000 for the 1983 cohort revealed that inpatients were arrested with the highest frequency (78/1,000), followed by emergency patients (53.5/1,000), then by outpatients (36.6/1,000) Similarly, in the 1975 cohort, inpatients were arrested at a higher rate (41/1,000) compared to 40/1,000 for outpatients. No emergency data were available for this year. Factors that were found to predict arrest were the diagnosis of antisocial personality disorder, number of prior arrests, and younger age, however, together, these variables explained only 5% of the total variation. Most of the arrests were for non-violent offenses.

Conclusions: Community mental health centre patients were found to have arrest rates that were substantially lower than rates reported in the literature for state hospital patients. As persons with mental illness  treated in a broad spectrum of mental health settings are included in the analysis of arrest rates, the discrepancy between arrest rates of patient samples and the general population will be reduced.

Comment: Given that the bulk of studies have followed hospitalized cohorts, this study adds an important dimension to this area of knowledge, especially given the emphasis on community mental health care. This study quantifies the magnitude of selection bias that can be expected when different psychiatric populations are used as study cohorts and reinforces the need to construct cohorts that are representative of all persons with mental illness.

Lagos, J.M., Perlmutter, K. and Saexinger, H. (1977). Fear of the mentally ill: Empirical support for the common man's response. American Journal of Psychiatry, 134(10), 1134-1137.

Purpose and Objective: The authors examined hospital records of psychiatric patients to determine how frequently people behave violently when they become mentally ill.

Research Design: Cross-sectional survey of hospital records.

Setting: New Jersey, United States of America.

Study Subjects: Study subjects comprised a random sample of 400 patients admitted during 1974, 100 to each of the 4 psychiatric facilities in New Jersey.

Measures: Admission notes were reviewed for any description of violent behaviour that was recent and presented as part of the basis for admission. Behaviours included attacks on persons or objects, threats to persons, verbal attacks on persons, ambiguous violence (e.g. non-specific descriptions), and loss of impulse control.

Main Findings: Of the 400 admissions reviewed, 37.7% manifested some form of violent behaviour with 20% specifically acting violent toward other persons or objects. The percentage of individuals who were described as having attacked other persons varied considerably from hospital to hospital from a high of 21.6% to a low of 4.4%. Of the 115 mentally ill whose records showed violent behaviour, only 3 were arrested.

Conclusions: The authors conclude that there may be considerable violent behaviour associated with mental breakdowns. To be more accurate, they should have noted that there may be considerable violent behaviour associated with hospitalizations for mental illness.

Comment: This study was chosen for inclusion because it illustrates: (a) a high proportion of patients are admitted to hospital because they are violent; and (b) the proportion of violent patients varies considerably from hospital to hospital. This study illustrates the biases inherent in hospitalized samples of mentally ill. The finding that only 3 of the 115 violent mentally ill were arrested highlights the potential for errors due to misclassification when making causal inferences concerning  the relationship between mental illness and violence from institutional admission data describing hospitalizations or arrests. Not all violent acts are reflected in arrest statistics.

Steadman, H.J., Venderwyst, D. and Ribner, S. (1978). Comparing arrest rates of mental patients and criminal offenders. American Journal of Psychiatry, 135(10), 1218-1220.

Purpose and Objective: To compare the arrest rates of former mental patients and criminal offenders to the general population to determine if prior criminality, rather than mental illness, is the root cause of observed differences.

Research Design: Unspecified by authors. Data presentation suggests a follow-up design with a one year variable follow-up period (i.e. persons discharged during the latter part of the year would have had less opportunity to be arrested compared to persons discharged during the early part of the year).

Setting: Albany Country, New York, United States of America.

Study Subjects: The authors selected two groups of mental patients and two groups of criminal offenders. Subjects were all those released from psychiatric centres (N=307), jails, and prisons (N=419) in 1968 and 1975.

Measures: Subsequent arrests comprise the main outcome measure. Violent crimes are not analyzed separately.

Main Findings: When broad comparisons were made, ex-patients had higher arrest rates compared to the general population, and criminal offenders had arrest rates that were higher than those of ex-mental patients. However, when previous criminality was taken into consideration, a different pattern emerged among ex-patients. Ex-patients who were arrested prior to their hospitalization were arrested more often than the general population. Ex-patients with no prior arrests were arrested about as often or less often than the general population.

Conclusions: The authors conclude that as the composition of state mental hospital has changed to include more individuals with prior criminal arrest records, the rates of arrests for patient samples has increased. Those mentally ill patients who have not been arrested (almost 75%) are arrested about as often or less often than the general population. It is the patient with multiple prior arrests who is often re-arrested upon release from a mental hospital.

Comment: Despite the potential for underestimating arrest rates in both ex-patient and offender groups, this study is important from a methodological perspective because it raises the issue that it is prior criminality, not mental illness per se, that results in higher subsequent arrests rates. Based on this finding,  subsequent research should: (a) develop cohorts for study that are at risk for violence or criminality by excluding individuals from study with prior histories; or (b) statistically control for prior history in the analysis.

Straznickas, K.A., McNiel, D.E. and Binder, R.L. (1993). Violence toward family caregivers by mentally ill relatives. Hospital and Community Psychiatry, 44(4), 385-387.

Purpose and Objective: This study assessed features of family relationships among hospitalized psychiatric patients that are associated with family members becoming targets of violence.

Research Design: Retrospective review of a case series.

Setting: A university-based, locked, short-term psychiatric inpatient unit in the United States of America. Based on the affiliations of the authors, the unit may be located in San Francisco, although this is not specified in the text.

Study Subjects: Study subjects were 581 patients admitted to the unit between 1983 and 1990.

Measures: Diagnostic information was abstracted from hospital files according to the ICD-9-CM final diagnosis. Indications of physical attacks on others were based on specific mentions of assault (hitting, pushing, or choking) during the two weeks prior to admission. Additional socio-demographic, interpersonal, and clinical data were abstracted from the charts.

Main Findings: Nineteen percent of the patients (N=113) had physically attacked someone in the two weeks prior to their admission, and of this, 31 had attacked more than one person. Of the 113 patients who attacked someone, 50 assaulted people outside of the family, 10 patients assaulted both family members and individuals outside of the family, and 53 assaulted family members.

Comment: As well as reinforcing selection bias in hospitalized samples, this study highlights the fact that when persons subsequently hospitalized for a mental illness became violent, family members were the most likely target. Without suitable comparison groups, however, it is not clear whether the relatives of the mentally ill are more likely to be the targets of violence compared to the relatives of the non-mentally ill. Nevertheless, this study suggests that family education programs that include information on early warning signs of decompensation, and how to react to aggressive escalation in ways that can minimize risk and result in improved adjustment may be helpful.

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