Mental Illness and Violence: Proof or Stereotype?

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Appendix A: Annotated Bibliography cont'd

Review Articles and Key Position Papers

The following articles either review the available literature or express innovative ideas regarding the interpretation of the literature. Many of the review articles are widely cited throughout the literature. Others are less frequently cited but convey important ideas or perspectives such as those that assess the applicability of findings to the Canadian situation. These reviews have not always used a critical, methodological perspective. At times, authors have accepted controversial findings with little scepticism. Despite these problems, these articles summarize a comprehensive list of publications relevant to the issue of mental illness and violence, and provide comprehensive references in the area. Because these are not empirical studies, a structured abstracting approach was inappropriate. Instead, key points that are relevant to the current critical review have been highlighted and, where appropriate, commentary has been provided.

American Psychiatric Association (1994). FACT sheet - violence and mental illness.

This fact sheet, designed for public consumption, summarizes what is known about the relationship between mental illness and violence. Recent research suggests that some mental illnesses increase the risk of violence, especially among patients with neurological impairments and psychoses, but that “chaotic, violent family environments in which alcohol or substance use is common, ongoing conflict among family members, and a controlling atmosphere (are) associated with violence by persons with mental illness”. The fact sheet also stresses that family members are at an increased risk of victimization by their mentally ill relatives rather than by the population at large, and that no clear-cut relationship exists between societal violence and the development of specific mental disorders.

Borzecki, M. and Wormith, J.S. (1985). The criminalization of psychiatrically ill people: A review with a Canadian perspective. The Psychiatric Journal of the University of Ottawa, 10(4), 241-247.

These authors review the various lines of argument and empirical studies undertaken in Canada and elsewhere that support the thesis that mentally ill persons are increasingly being criminalized through being diverted to the criminal justice system. Of special note is that Canadian data are provided to illustrate the deinstitutionalization of the mentally ill between 1962 and 1981. Data on government spending for psychiatric programs is shown to have increased over this time period and these authors argue that it is likely that much of these funds have been directed into short-term inpatient care. They suggest that these data indicate that the community mental health movement may not be as great a failure in Canada as it appears to have been in the United States. They caution that Canada may have superior community health facilities and, by virtue of a principle of universal access to inpatient and outpatient care, greater availability of appropriate services. Caution must, therefore, be exercised when generalizing findings from American studies to the Canadian situation.

Bradford, J. (1994). Violence and mood disorder: Forensic issues and liability concerns. The  Canadian Review of Affective Disorders, 5(2), 1-7.

This review on the issue of violence and mental illness contains a reference to the American Epidemiological Catchment Area studies, specifically the analysis of the data by Swanson et al. (1990) as to the independent role of psychosis as a trigger to violent behaviour. Bradford also mentions some of the PET (positron-emitting tomography) studies and those implicating low serotonin levels in violence. Bradford then addresses more specific forensic issues with respect to clinical aspects of violence in depression, management concerns, and legal liabilities, in particular, prediction and duty to warn.

Cohen C.I. (1980). Crime among mental patients—a critical analysis. Psychiatric Quarterly, 52(2), 100-107.

Cohen provides an excellent methodological critique of the literature, illustrating how previous research examining criminality among discharged mental patients has been characterized by methodological flaws. As a result, the question of whether former patients are more dangerous than the general public remains unanswered. Among the methodological difficulties noted were: (a) lack of comparability across studies with respect to time, setting, and geography; (b) a lack of control for pertinent confounding factors such as demographic variables or prior criminality; (c) some sample sizes too small to reliably detect rare events such as violence; (d) lack of differentiation among diagnostic categories; and (e) over-reliance on arrest records to measure crime without taking into consideration crimes committed or actual convictions. Cohen concluded that without more carefully controlled studies, we must be circumspect about attributing criminality to discharged mental patients.

Davis, S. (1991). An overview: Are mentally ill people really more dangerous? Social Work, 36(2), 174-180.

Davis provides an excellent methodologically-oriented review, highlighting problems in previous studies that have the potential to alter the conclusions of the studies. He argues that an objective and systematic study of the issue of mental illness and dangerousness is crucial to the formulation of appropriate and effective policies for the provision of community mental health services. Davis points out that it has become fashionable to imply that the mentally ill are somehow more dangerous than the non-mentally ill. Advocates for the mentally ill have pointed out that the media have exaggerated the crime rates of mentally ill people and have fostered this stereotype through selective reporting. While objective research will do much to resolve these issues, research in this area has traditionally been plagued by methodological problems. For example, most studies have focussed on biased samples of institutional populations who tend to be more disabled and “acting out” than the general  population of persons with mental illness. These studies may overestimate the relationship between mental illness and violence. Similarly, following released patients may underestimate the potential for violence because only those with the best prognosis will be released. Similarly, there have been problems in the definition and measurement of dangerousness. The majority of studies have used arrest rates. This is problematic because studies have shown that mentally ill persons may be arrested at a disproportionately higher rate than non-mentally ill persons, thus giving an over-estimation of the criminality of the mentally ill. A third problem is the lack of control for confounding factors that predict criminality in the general population (e.g. age, sex). When factors are considered appropriately, much of the difference in mentally ill and general population groups disappears. A small criminal subset who may have been inappropriately diverted into the mental health system may account for the majority of crime. Given present research, Davis concludes that the answer to the question of mental illness causing violence remains inconclusive.

Davis, S. (1991). Violence by psychiatric inpatients: A review. Hospital and Community Psychiatry, 42(6), 585-590.

Davis begins his review of the literature on inpatient violence with an analysis of the incidence, prevalence and changing rates of inpatient violence. He then categorizes the factors affecting these rates into three categories: (1) individual; (2) situational; and (3) structural. In regards to the incidence and prevalence of inpatient violence, Davis concludes that variations in methodology have made it difficult to determine the extent of violence in psychiatric facilities. He explains that studies of inpatient violence are hard to compare because of differing definitions of violence, and the variety of settings in which the studies have taken place ranging from general hospital to psychiatric to forensic facilities. In general, the rates of inpatient aggression have ranged from 2.54 assaults per bed per year to 7-10% of patients involved in assaults during a 1-3 month period of observation. Overall, serious assaults are rare. A number of researchers have found that a majority of the incidents are conducted by a minority of patients.

Cross-cultural comparisons indicate that rates of violence tend to be higher in the United States than in other countries. One study for example showed that the total number of violent incidents during one year in the 28 New York State psychiatric facilities totalled 2,000, compared to only 311 violent assaults in all similar British facilities over 3 1/2 years. Davis concludes that studies have revealed several factors that may be predictive of violence in inpatient settings. Among them are the presence of psychosis and phase of illness. Compared to age and a history of violent behaviour, sex may not be a very useful discriminating factor. At the institutional level, a certain amount of violence may be inevitable in the process of  dealing with involuntary, treatment-resistant patients. Factors such as overcrowding, provocation from staff and other patients, staff expectations and inexperience, and poor management practices may affect violence. Factors at the structural level such as a shortage of beds and community resources may also affect the occurrence of violence.

Based on the evidence thus far, violence appears to be the result of an interaction of multiple factors. A model of violence is presented, which considers a variety of factors including clinical, individual, situational and structural factors.

Davis, S. (1992). Assessing the “criminalization” of the mentally ill in Canada. Canadian Journal of Psychiatry, 37, 532-538.

Davis indicates that no studies on the criminalization of the mentally ill have been conducted in Canada and cautions that American findings may not be generalizable to this country. He analyzes the factors that contribute to the American findings and provides a detailed account of the extent to which these might also be operating in Canada. For example, deinstitutionalization, coupled with the absence of community support systems, is widely agreed to have placed greater numbers of patients at risk of perpetrating violence while in the community. In Canada in 1955, 4.24 patients per 1,000 were hospitalized; this had decreased to 0.7 by the early 1980's. However, Canada's universal health care system may provide for greater access to community services than in the American setting. Davis also examines the role of police in diverting mental patients to emergency resources and discusses the “psychiatrization of criminals” thesis as one explanation for the higher prevalence of mental illness among incarcerated offenders. In general there is a paucity of Canadian research bearing on these issues. To fully assess these trends, more Canadian research will be necessary.

Garza-Treviño, E. (1994). Neurobiological factors in aggressive behaviour. Hospital and Community Psychiatry, 45(7), 690-699.

This is a review of the literature on the neurosciences and psychiatric clinical research about biological factors in aggression in neuropsychiatric syndromes. The author conducted a computer search of publications on the neurobiological components of aggression published in the past 25 years (1977-1993). Studies were divided into four groups: (1) animal models of aggression using EEG recordings during chemical and electrical stimulation of areas of the brain; (2) EEG studies of human brains in normal and pathological states; (3) neuropathological and neuroimaging studies using CAT, MRI and PET (positron-emitting tomography) to detect morphological abnormalities in brains of abnormally aggressive subjects; and (4) neuropsychological studies of the prevalence of psychological impairments among recurrently violent mentally ill patients.

The author concludes that aggressive behaviour accompanying psychopathological states is multidetermined. With the exception of psychosocial or economic influences, possible causes of such aggression include lesions to inhibitory centres of the brain, chemical stimulation of rage centres through drugs or seizures, subtle molecular damage to receptors that may be hereditary or acquired, or dysfunction of neuronal networks. Studies suggest that aggressive behaviour is associated with: (1) damage to centres of the brain located in the limbic structures, temporal lobes, and frontal lobes apart from possible damage to connections between the amygdaloid complex and the hypothalamus and between the hyppocampal cortex and the frontal lobes; and (2) deficiency or dysregulation of serotonin, “low serotonin syndrome”, and potentially other neurotransmitters such as norepinephrine, dopamine and glucose. In addition, effects of seizures, drugs and alcohol seem related to alteration of inhibitory mechanisms and subsequent release of pre-existing behavioural patterns through a process of kindling.

Gunn, J. (1977). Criminal behaviour and mental disorder. British Journal of Psychiatry, 130, 317-329.

Similar to Mesnikoff and Lauterbach (1976) (see below), Gunn provides a detailed summary of previous findings, but without a serious methodological critique. Nevertheless, he does identify problems in defining violence and criminality, as well as the selective view resulting from the focus on institutional populations that systematically exclude the bulk of mental patients or criminals. He concludes that it is probably best to avoid generalizations about mental disorder and criminality and focus, instead, on specific behaviour problems associated with specific disorders.

Haller, R.M. and Deluty, R.H. (1988). Assaults on staff by psychiatric inpatients: A critical review. British Journal of Psychiatry, 152, 174-179.

The paper reviews the literature concerned with assaultive acts committed by psychiatric patients during hospital stay, and with the contextual factors and patient characteristics associated with such assaults. Based on the findings, the authors attribute increased risk of assault to a variety of factors: (1) understaffed units; (2) deinstitutionalization; (3) an increasing number of readmissions and involuntary admissions; (4) patients' right to refuse medication, often leading to an increase in patient/staff confrontations; (5) diverse mixtures of patients and; (6) patients being younger and more difficult to manage than in past years. Although assaults on staff have apparently increased in recent years, a number of studies indicate that the vast majority of psychiatric patients are not assaultive. There appears to be a small core of patients, typically 7-10% of the total population, who display assaultive behaviour that is dangerous enough either to be worthy of mention in nursing reports, or to  cause an injury and therefore require the completion of an injury report.

Hodgins, S. (1994). Editorial: Schizophrenia and violence: Are new mental health policies needed? Journal of Forensic Psychiatry, 5(3), 473-477.

Hodgins suggests that evidence is mounting to indicate that patients with schizophrenia are likely to engage in aggressive behaviour toward others when in the community and she summarizes several lines of evidence supporting this position. She argues that the community mental health movement which closed mental hospitals and treated persons suffering from major mental disorders in the community can be considered to be a failure. Polices governing the treatment of persons suffering from schizophrenia must be developed taking into account the public's right to safety, although Hodgins does not specify what these policies might be.

Link, B.G. and Stueve, A. (1995). Evidence bearing on mental illness as a possible cause of violent behaviour, Epidemiologic Reviews, 17(1), 172-181.

This is an excellent and up-to-date review of the literature on this subject. The authors point out that there are three reasons why it is important to establish whether or not there is a relationship between mental illness and violence: public safety; quality of life and well being of mental patients; and the consequences for those who commit violent acts (lawsuits, prison, et cetera).

The authors indicate that several types of studies point towards the presence of a relationship between mental illness and violence. The list of these studies and the comments of the authors are outlined as follows:

(1) Arrest-rate studies of discharged psychiatric patients. Criticism of these studies fall into three categories: “criminalization of mental illness” whereby the arrest rates tell more about the arrest process than about an association between mental illness and criminality; “psychiatrization of criminal behaviour”, i.e., a tendencey to attribute a psychiatric diagnosis to behaviours that were previously considered to be predominantly antisocial and criminal; and “design” issues in studies that compare mental patients from public facilities (i.e. highly selected) with rates in the general population.

(2) Conviction rate studies of birth cohorts based on case registers (such as the studies in the Scandinavian countries). These studies have shown a higher risk of criminality among individuals who suffer from mental conditions. Link and Stueve note that although birth cohort studies have better generalizability than arrest-rate studies, they suffer from an inability to account for the temporal ordering of factors (which comes first, criminality or mental condition) and hence cannot be used to infer  cause.

(3) Arrest-rate studies based on a prevalence study of mental disorder (such as some of those conducted within the Epidemiological Catchment Area studies). This type of study observes community-dwelling respondents and investigates whether those with a history of mental illness are more likely to report a history of arrest. These population-based studies avoid selection biases and allow for the study of multiple confounding factors. However, temporal ordering of factors, unspecified criminality (as opposed to just violent behaviour) and lifetime prevalence measures of some mental disorders are considered weaknesses of this type of study.

(4) Studies that incorporate self-reported violent behaviour while using community controls (such as some studies conducted within the Epidemiological Catchment Area studies). Contrary to the first three types of studies that depend on arrest rates, studies on self-reported violence do not necessarily involve arrest and are, therefore, more comprehensive. According to the authors, differences in violent behaviour between patients and non-patients as provided in these studies “are not artifactual but real”. The authors, however, indicate that these studies suffer as well from methodological weaknesses and unclear ordering of temporal factors.

(5) Studies of “threat/control override” symptoms. These are theory-driven studies purporting to show an association between mental illness and violence when there is a perception of threat and/or override of personal controls. The authors argue that this type of study controls factors such as social desirability and temporally ordered variables and give, therefore, strong support to an association between mental illness and violence.

The authors conclude their review by indicating that there are four perspectives on the association of mental illness and violence: (a) that there is no association, let alone causal, and that this is refuted by mounting evidence to the contrary; (b) that there is an association but that it is spurious because of methodological limitations. However, this is counteracted by consistency of findings across studies so that the limitations in some are controlled by the strengths in others and vice versa; (c) that the association is causal and that this is proven by the consistency of the findings across different methodological approaches and by failure of an alternative, competing hypothesis; and (d) there is an association but it is mediated by multiple social factors. The authors indicate that this perspective could very well provide the explanation needed for the association, and that “it is possible that mental illness only leads to violent behaviour under certain conditions”. This context, they conclude, “deserves further scrutiny and specification”.  Finally, the authors recommend epidemiological studies with better measures and more adequate designs. Specifically, they recommend an epidemiological cohort design that (a) specifies the mental disorder(s) of interest, (b) follows representative samples of people with no history of the mental disorder(s) of interest and people experiencing the first episode of the disorder(s), and (c) compares the subsequent involvement of the groups in violent acts.

Mesnikoff, A.M. and Lauterbach, C.G. (1976). The association of violent dangerous behaviour with psychiatric disorders: A review of the research literature. Journal of Psychiatry and the Law, 3: 415-445.

These authors provide a detailed summary of research in four areas: (a) psychiatric disorders among criminal offenders; (b) violence among former psychiatric inpatients; (c) violence related to organic brain dysfunction; and (d) prediction of violence occurring among psychiatric patients. Interestingly, they note that studies conducted prior to 1960 show that ex-patients have rates of violent criminal behaviour that are no greater, or smaller than the general population. Later studies report that psychiatric patients released into the community display as much violent crime and, in some groups, more, than the general population. Unfortunately, the authors do not critically assess the methods used in these studies. No explanation is given for the discrepancy in findings between early and later studies.

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