Probability and loss: two sides of the risk assessment coin

Abstract

Assessment of the probability of future harm, often referred to as a 'risk assessment', has been widely adopted in mental healthcare settings in an attempt to reduce the incidence of violence and self-harm. The aim of risk assessment is to identify individuals who are at greater risk of harm and provide those patients with a higher level of treatment and supervision, thereby reducing the incidence of harm. The term 'risk assessment' is used in a variety of ways, from the opinion of an experienced clinician about dangerousness to the use of a score derived from a checklist of factors associated with a range of harmful behaviours, particularly violence to others or suicide. The ability to assess risk is regarded as an essential skill for mental health practitioners 1 and the practice guidelines issued by governments and by professional bodies suggest that we are able to predict and prevent many forms of harm. [2][3][4] Assessing whether an individual is likely to harm themselves or others is part of the mental health law in most high-income countries, 5-7 and the routine use of structured instruments to estimate the probability of future harm, often referred to as actuarial methods, are widely believed to be a way of reducing the incidence of violence 8-12 and self-harm. [13][14][15] Criticisms of risk assessment have been made on statistical, ethical and empirical grounds. Statistical arguments note the lack of accuracy of predictions and highlight both the high rates of false-positive predictions for most forms of harm and the failure to identify many cases. [16][17][18][19][20] Ethical arguments against risk assessment include the potential for the denial of care to those classified as at low risk 7 and the discriminatory treatment of people who have been categorised as being at high risk but do not go on to cause or experience harm. 21,22 Another ethical problem with risk assessment is the way it devalues patients by underestimating their capacity for choice 23 and alienates them from participating in decisions about their own care. 24 The empirical arguments against risk assessment include the near complete absence of published evidence that the adoption of risk assessment can result in a reduction in any form of harm. The one exception to this is a clusterrandomised trial of nine psychiatric wards that examined violence for 3 months after the adoption of structured risk assessment. 9 This study reported a significant reduction in violence in the experimental wards. However, the two groups of wards were not matched for levels of violence before the trial and after the intervention the incidence of violence in the experimental wards returned to the level of the control wards, suggesting that the results obtained were a result of regression to the mean rather than a true effect. 25 Moreover, the vast majority of predictions of harm were false positives. A more recent study, also of violence in psychiatric wards found that violence risk assessment was not associated with a sustained reduction in violent incidents...

Stalking risks to celebrities and public figures

“…Large & Nielssen (2011) advocate focusing on the welfare of the patient rather than the current preoccupation with risks of suicide or violence. This view has some merit, as it is not possible to predict what any individual will do.…”

Does the emphasis on risk in psychiatry serve the interests of patients or the public? No

“…6 Although structured risk assessments for violence or suicide are known to be more accurate than clinical judgments, clinicians dislike them. This is because even an accurate estimate of the probability of a suicide or violence is of little use to them as they help patients and families with decisions about the benefits and side effects of mental healthcare.…”

A human right to be detained? Mental healthcare after ‘Savage’ and ‘Rabone'

“…12 They may take significant time to complete 13 and their usefulness in routine clinical practice has been frequently questioned. 13,14 Furthermore, owing to the inherent trade-off between sensitivity and specificity of any assessments or tools, trying to provide restrictive care for all 'truly' suicidal patients is likely to increase the number of patients who are 'falsely' designated as high risk and receive restrictive care, [6][7][8][9][10] perhaps unethically so. In summary, emphasis on 'real and immediate' risk which could be 'foreseen' is likely to encourage clinicians to adopt defensive medical practices, without any discernible benefits to the patients.…”