The focus on assessing dangerousness in routine psychiatric practice developed when relatively little was known about factors related to violence, and the accuracy of predicting violence was distinctly below chance. Since the 1990s, however, significant research attention has been directed toward factors related to violence and mental illness, as well as toward factors related to the accuracy of risk assessment techniques. Sociodemographic and environmental variables have been identified as significant predictors of violence, as has the presence of substance abuse. However, the data on specific mental health variables are somewhat mixed. Many studies point to a modest increased risk of violence associated with major mental illness and psychosis, whereas other noteworthy studies have failed to confirm such findings. Studies of the accuracy of risk assessments indicate that both actuarial and clinical methodologies perform better than chance, although the former achieve greater statistical accuracy. Despite ongoing controversies, risk management strategies that encompass the strengths and limitations of our present knowledge are available to clinicians.
(Can J Psychiatry 2005;50:18-26)
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Key Words: clinical risk assessment, actuarial risk assessment, research, correlates of violence, prediction of violence
In 1990 President George HW Bush proclaimed the next 10 years as the "decade of the brain" (1). The proclamation's purpose was "to enhance public awareness of the benefits to be derived from brain research" (1).The year 1990 also marks the beginning of the contemporary era of research on mental illness and violence. However, despite significant advances in knowledge about risk assessment and the correlates of violence, a 1996 study of public opinion demonstrated increasing public consciousness of an association between mental illness and "dangerous[ness] to self or others" (2).
The paradigm of dangerousness evolved in the 1960s and 1970s from the confluence of at least 3 sociopolitical movements related to psychiatry and from the legal cases that highlighted them (3). The first of these was the deinstitutionalization movement, which, in creating an alternative option to hospital care, emphasized the need for criteria to decide between inpatient and outpatient care. The second movement was the increased use of voluntary hospitalization for psychiatric patients. In 1971 most psychiatric patients in the US were for the first time hospitalized voluntarily (4). With the advent of the popular use of voluntary hospitalization came the demand for involuntary hospitalization criteria that could withstand the increased scrutiny levelled at involuntary commitments. The third variable was the civil rights movement, which spawned an increase in libertarian advocacy for persons with mental illness; the highest possible standards were sought for the involuntary deprivation of liberty occasioned by civil commitment. Various civil commitment cases confirmed repudiation of the parens patriae standard and reliance on government police powers and the dangerousness standard (according to which dangerousness to self or others becomes the principal determinant of eligibility for involunatry commitment) (5-8).
Despite widespread adoption of the dangerousness standard in commitment proceedings and extension ofthat standard to psychiatric outpatients (9-11), capital defendants (12,13), and insanity acquittees (14), no data supported the idea that psychiatrists or other mental health professionals could reliably determine future dangerousness. In fact, Monahan's 1981 review of the literature demonstrated that mental health professionals were wrong in 2 out of 3 attempts to predict dangerousness (15).
Prominent forensic mental health professionals (16-19) and the American Psychiatric Association (20) attempted to critique this new paradigm and modify its evolution in mental health care. …