RELATIONSHIP BETWEEN MENTAL HEALTH AND VIOLENCE
The relationships between mental illness and violence has a significance effect on mental health practice and policy, guides allocation of the limited resources in the mental health and criminal justice systems, and serves as the basis for imposing mandatory treatment to protect public safety at the expense of patients self –determination and liberty.
The scientific literature on the association between mental illness and violence is inconclusive for several reasons. First, to establish that mental illness causes violence, it is necessary (though not sufficient) to demonstrate that mental illness precedes later violence; however, cross sectional epidemiological studies analyze correlations between past violence and current or lifetime psychiatric diagnoses. Second, when research has been longitudinal, it has primarily focused on the risk of violence for individuals already in clinical or institutional settings instead of samples representative of the general population.
Research using those longitudinal samples has contributed substantially to understanding important risk factor for violence in people with mental illness but, by virtue of the inclusion criteria used, is arguably limited in describing whether or to what extent severe mental illness is an independent risk factor for violence. Third, empirical studies often combine all violent acts into one composite variable owing to limited statistical power to distinguish specific forms of violent acts (eg, substance-related violence, severe violence with weapons), leaving unanswered the question of whether mental illness predicts some kinds of violence but not others.
This societal bias contributes to the stigma faced by those with a psychiatric diagnosis, which in turn contributes to non-disclosure of the mental illness and decreased treatment seeking, and also leads to discrimination against them. The association of violence and mental illness has received extensive attention and publicity. Public perception of the association between mental illness and violence seems to have fuelled the arguments for coerced treatment of patients with severe mental illness.
However, this perception is not borne out by the research literature available on the subject. Those with mental illness make up a small proportion of violent offenders. A recent meta-analysis by Large et al found that in order to prevent one stranger homicide, 35 000 patients with schizophrenia judged to be at high risk of violence would need to be detained. This clearly contradicts the general belief that patients with severe mental illness are a threat
MAGNITUDE OF THE PROBLEM-
There are numerous ways of conceptualizing the definition of violence, although at present there is no consensus as to which of these is the most appropriate. The WHO has defined violence as ‘the intentional use of physical force or power, threatened or actual, against oneself, another person, or against a group or community, that either results in or has a high likelihood of resulting in injury, death, psychological harm, mal-development or deprivation’. This definition includes threats, intimidation, neglect and abuse (whether physical, sexual or psychological), as well as acts of self-harm and suicidal behavior. Although expansive and all-encompassing, it defines violence in terms of its outcomes on health and well-being rather than it characteristics as a construct that is socially or culturally determined.
Studies investigating the prevalence of violence in psychiatric patients show a wide variability, in accordance with the treatment setting in which they were conducted. The lowest prevalence rates of violence have been seen in outpatient settings (2.3–13%), and the highest in acute care settings (10–36%) and involuntarily committed patients (20–44%). Around 10% of the patients with schizophrenia or other psychotic disorders behave violently, compared with less than 2% of the general public.
Although this suggests that mental illness does contribute to the risk of violence, it is important to note that the 1-year population-attributable risk (PAR) of violence associated with serious mental illness alone was found to be only 4% in the ECA (Epidemiologic Catchment Area) survey. This implies that even if the elevated risk of violence in people with mental illness is reduced to the average risk in those without mental illness, an estimated 96% of the violence that currently occurs in the general population would continue to occur. Although a statistical relationship with violence has been demonstrated in certain severe mental disorders such as schizophrenia, however, only a small proportion of the societal violence can be attributed to persons suffering from mental disorders.
The dynamic interaction of social and contextual factors with the clinical variables plays an important role as a determinant of violence. However, these issues have not generated sufficient interest and the emphasis continues to be on the psychiatric diagnosis or clinical variables of the patient, while looking for causal factors of violence.
ARE MENTALLY ILL PEOPLE VIOLENT?
Many psychiatrists, particularly those working in emergency or acute care settings, report direct experiences with violent behavior among the mentally ill. In Canada, for example, where violence in the population is low relative to most other countries, the majority of psychiatrists are involved in the management and treatment of violent behavior, and 50% report having been assaulted by a patient at least once. However, clinical experiences with violence are not representative of the behaviors of the majority of mentally ill. Social changes in the practice of psychiatry, particularly the widespread adoption of the dangerousness standard for civil commitment legislation, means that only those with the highest risk of violence receive treatment in acute care settings.
In fact, a serious limitation of clinical explanations of violent and disruptive behavior is their focus on the attributes of the mental illness and the mentally ill to the exclusion of social and contextual factors that interact to produce violence in clinical settings. Even in treatment units with a similar clinical mix and acuity, rates of aggressive behaviors are known to differ dramatically, indicating that mental illness is not a sufficient cause for the occurrence of violence. Studies that have examined the antecedents of aggressive incidents in inpatient treatment units reveal that the majority of incidents have important social/structural antecedents such as ward atmosphere, lack of clinical leadership, overcrowding, ward restrictions, lack of activities, or poorly structured activity transitions.
The public are no less accustomed to ‘experiencing’ violence among the mentally ill, although these experiences are mostly vicarious, through movie depictions of crazed killers or real life dramas played out with disturbing frequency on the nightly news. Indeed, the global reach of news ensures that the viewing public will have a steady diet of real-life violence linked to mental illness. The public most fear violence that is random, senseless, and unpredictable and they associate this with mental illness. Indeed, they are more reassured to know that someone was stabbed to death in a robbery, then stabbed to death by a psychotic man. In a series of surveys spanning several real-life events in Germany, Anger meyer and Matschinger showed that the public’s desire to maintain social distance from the mentally ill increased markedly after each publicized attack, never returning to initial values. Further, these incidents corresponded with increases in public perceptions of the mentally ill as unpredictable and dangerous.
In some countries, such as the United States, public opinion has become quite sophisticated. The public judge the risk of violence differently, depending on the diagnostic group, with rankings that broadly correspond to existing research findings. For example, Pescosolido surveyed the American public (N=1,444) using standardized vignettes to assess their views of mental illness and treatment approaches. Respondents rated the following groups as very or somewhat likely of doing something violent to others: drug dependence (87.3%), alcohol dependence (70.9%), schizophrenia (60.9%), major depression (33.3%), and troubled (16.8%). While the probability of violence was universally overestimated, respondents correctly ranked substance abusers among the highest risk groups. Similarly, they significantly overestimated the risk of violence among schizophrenia and depression, but correctly identified these among the lower ranked groups.
Public perceptions of the link between mental illness and violence are central to stigma and discrimination as people are more likely to condone forced legal action and coerced treatment when violence is at issue. Further, the presumption of violence may also provide a justification for bullying and otherwise victimizing the mentally ill. High rates of victimization among the mentally ill have been noted, although this often goes unnoticed by clinicians and undocumented in the clinical record. In a study of current victimization among inpatients, for example, 63% of those with a dating partner reported physical victimization in the previous year. For a quarter, the violence was serious, involving hitting, punching, choking, being beaten up, or being threatened with a knife or gun. Forty-six percent of those who lived with family members reported being physically victimized in the previous year and 39% seriously so. Three quarters of those reporting violence from a dating partner retaliated, as did 59% of those reporting violence from a family member. In addition, many people with serious mental illnesses are poor and live in dangerous and impoverished neighbourhoods where they are at higher risk of being victimized. A recent study of criminal victimization of persons with severe mental illness showed that 8.2% were criminally victimized over a four month period, much higher than the annual rate of violent victimization of 3.1 for the general population. A history of victimization and bullying may predispose the mentally ill to react violently when provoked.
Violent victimisation of the mentally ill-
Patients with severe mental illness constitute a high-risk group vulnerable to fall victims to violence in the community. Symptoms associated with severe mental illness, such as impaired reality testing, disorganized thought processes, impulsivity and poor planning and problem solving, can compromise one’s ability to perceive risks and protect one self and make them vulnerable to physical assault.
Violent victimisation of persons with severe mental illness presents obvious dangers of physical trauma and impairs the quality of patients’ lives. Past traumatic and victimisation experiences have been found to be significantly associated with patients’ symptom severity and illness course. However, this issue has attracted much less attention than violent behavior by the patients, in spite of the fact that violent victimisation of patients occurs more frequently than violent offending by the patient.
Recent review reported that the prevalence of violent victimisation ranges between 7.1% and 56%, although the issue of comparability among the studies exists. Young age, comorbid substance use and homelessness were found to be the risk factors for victimisation. A relationship between victimisation and violent behavior by patients with severe mental illness has also been suggested in numerous studies. However, it is not clear whether past victimisation predicts future violence, or past violence predicts future victimisation, or both.
ARE MENTALLY ILL AT INCREASED RISK OF VIOLENCE?
Scientists are less interested in the occurrence of isolated acts of violence among those with a mental illness, and more interested in whether the mentally ill commit acts of violence with greater frequency or severity than do their non-mentally ill counterparts. Therefore, the question of whether the mentally ill are at a higher-than-average risk of violence is central to the scientific debate.
Definitive statements are difficult to make and it is equally possible to find recent literature supporting the conclusions that the mentally ill are no more violent, they are as violent, or they are more violent than their non-mentally ill counterparts. Prior to 1980, the dominant view was that the mentally ill were no more, and often less likely to be violent. Crime and violence in the mentally ill were associated with the same criminogenic factors thought to determine crime and violence in anyone else: factors such as gender, age, poverty, or substance abuse. Any elevation in rates of crime or violence among mentally ill samples was attributed to the excess of these factors. When they were statistically controlled, the rates often equalized. However, although the main risk factors for violence still remain being young, male, single, or of lower socio-economic status, several more recent studies have reported a modest association between mental illness and violence, even when these elements have been controlled.
Because of the significant methodological challenges faced by researchers in this field, the nature of this association remains unclear. For example, violence has been difficult to measure directly, so that researchers have often relied on official documentation or uncorroborated self-reports. The prevalence of violence has been demonstrated to differ dramatically depending on the source. Most samples have not been representative of all mentally ill individuals, but only of those with the highest risk of becoming dangerous, such as those who are hospitalized or arrested. Study designs have not always eliminated individuals with a prior history of violence (a major predictor of future violence), controlled for co-morbid substance abuse, or clearly determined the sequencing of events, thereby weakening any causal arguments that might be made.
The MacArthur Violence Risk Assessment Study recently completed in the United States has made a concerted effort to address these problems, so it stands out as the most sophisticated attempt to date to disentangle these complex interrelationships. Because they collected extensive follow-up data on a large cohort of subjects (N=1,136), the temporal sequencing of important events is clear. Because they used multiple measures of violence, including patient self-report, they have minimized the information bias characterizing past work. The innovative use of same-neighbor comparison subjects eliminates confounding from broad environmental influences such as socio-demographic or economic factors that may have exaggerated differences in past research.
In this study, the prevalence of violence among those with a major mental disorder who did not abuse substances was indistinguishable from their non-substance abusing neighborhood controls. A concurrent substance abuse disorder doubled the risk of violence. Those with schizophrenia had the lowest occurrence of violence over the course of the year (14.8%), compared to those with a bipolar disorder (22.0%) or major depression (28.5%). Delusions were not associated with violence, even ‘threat control override’ delusions that cause an individual to think that someone is out to harm them or that someone can control their thoughts. Previous cross-sectional studies conducted in the United States and Israel had linked threat-control override delusions to an increased risk of violence.
The importance of substance abuse as a risk factor for violence has been well articulated in other studies. Consequently, this may stand out as one of the robust clinical findings in the field. Substance abuse in the context of medication non-compliance is a particularly volatile combination and poor insight also may be a factor.
Predictors of violent behaviour
The relationship between mental illness and violence has been shown to be more complex than initially suspected. From viewing mental illness as a causative agent, researchers after reanalyzing the NESARC (National Epidemiologic Survey on Alcohol and Related Conditions) data have confirmed that mental illness and violence are related primarily through the accumulation of risk factors of various kinds, for example, historical (past violence, juvenile detention, physical abuse, parental arrest record), clinical (substance abuse, perceived threats), dispositional (age, sex, etc) and contextual (recent divorce, unemployment, victimisation) among the mentally ill. In fact, for those with mental illness without substance use, the relationship with violence was modest at best.
With the growing repertoire of risk assessment tools, mental health professionals are often expected to predict and manage violent behavior, especially in an acute care setting. Diagnostically, aggressive behavior has been linked to schizophrenia, mania, alcohol abuse, organic brain syndrome, seizure disorder and personality disorders. Among patients in acute psychiatric settings, young age, male sex, history of psychiatric illness, co morbid substance abuse and positive symptoms have been shown as consistent predictors of violent behavior. Among these, the history of violence is often emphasized as the most significant predictor of future violence. However, overall, the identified risk indicators of violent behavior have poor predictive validity, in the short-term and the long-term. Large epidemiological studies like the ECA study also found a substantially increased risk of violent behavior specifically within particular demographic subgroups of participants: younger individuals, males, those of lower socioeconomic status and those having problems involving alcohol or illicit drug use. These risk factors were statistically predictive of violence in people with or without mental illness.
RESEARCH AND PUBLIC HEALTH CHALLENGES
The assessment of violence-specific risk prediction in the past studies presents several limitations: unclear definition of violence, use of non-standardized scales for the evaluation of aggressive behavior, non-homogeneous samples, absence of control groups and of prospective design in the majority of the studies. These limitations might explain the heterogeneity of conclusions drawn by various studies, and particularly the wide variations in risk ratios for mental illness as a contributor to the violence. An attempt to resolve this heterogeneity is important from a public health perspective as the association of violence with mental illness hampers community reintegration of people with schizophrenia.
Also, most studies have primarily examined the association between violence and severe mental illness, for example, schizophrenia, in terms of relative risk (ie, the amount of risk posed by those with schizophrenia relative to others). However, there is a dearth of literature on indices of greater public health significance, such as PAR %: the percentage of violence in the population that can be ascribed to schizophrenia and thus could be eliminated if schizophrenia was eliminated from the population. A shift of research focus from relative to attributable risk will help provide a more balanced picture and prevent unnecessary stigmatization of people suffering from severe mental illness. Another major issue is that, since causality between mental illness and violent behavior cannot be definitively determined, these indices need to take into account the various social-related, contextual-related and co morbidity-related factors which would act as confounders. Better ways are required for presenting risk magnitudes in a comprehensive manner.
The public health importance of resolving these issues is, to a certain extent, in disassociating mental illness from the concept of dangerousness. Any attempt to resolve these issues must begin with an acceptable operational definition of violence, and clear distinctions between various types (towards self/others, verbal/physical, intended/actual, etc) for more consistent and reliable reporting.
Additionally, studies of violence among people with mental illness must go beyond linking various conditions or categories with rates or severity of violence, and instead include a careful examination of contextual and co morbid factors, so that the complex patterns of confounding may be unraveled. It is only with such an understanding that the appropriate intervention(s) might be formulated, and provided to patients at an appropriate time and setting.
Evidence regarding the effectiveness of psychotropic drugs on violent behavior as one of the treatment outcomes is not yet adequately researched. Moreover, investigating the effectiveness of specific psychotropic drugs on violent behavior as an outcome is also riddled with numerous challenges. Although pharmacoepidemiological studies provide an opportunity to assess the effectiveness of psychotropic drugs in reducing incidence of violent behavior, they are subject to a number of confounding factors. These studies have often failed to look into the individual, social, economic and contextual factors responsible for variability in the risk of violence in these patients. Similarly, randomized controlled trials to investigate the efficacy of drugs to reduce violence in particular are also mired with feasibility issues.
Violent patients are often difficult to recruit and the attrition rates are also high in such studies. Also, since the outcome has a lower rate of occurrence, the sample size of studies needs to be high. Moreover, conducting such studies will pose an ethical dilemma as violence in a psychiatric patient is considered as an acute emergency, warranting immediate intervention.
The relationship between mental illness and violent behaviour has serious implications from a public health perspective. Since current evidence is not adequate to suggest that severe mental illness can independently predict violent behaviour, public efforts are required to deal with the discriminatory attitude towards patients suffering from mental illness as potential violent offenders. The role of medication in controlling violent behaviour along with the target symptoms needs to be further clarified. Also, the role of individual and contextual factors in mediating violence remains to be explored further, and appropriate intervention strategies need to be formulated. Also, too much past research has focussed on the person with the mental illness, rather than the nature of the social interchange that led up to the violence. Consequently, we know much less than we should about the nature of these relationships and the contextual determinants of violence, and much less than we should about opportunities for primary prevention.