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Probability and loss: two sides of the risk assessment coin

  • Matthew M. Large (a1) and Olav B. Nielssen (a2)
Summary

Risk assessment has been widely adopted in mental health settings in the hope of preventing harms such as violence to others and suicide. However, risk assessment in its current form is mainly concerned with the probability of adverse events, and does not address the other component of risk – the extent of the resulting loss. Although assessments of the probability of future harm based on actuarial instruments are generally more accurate than the categorisations made by clinicians, actuarial instruments are of little assistance in clinical decision-making because there is no instrument that can estimate the probability of all the harms associated with mental illness, or estimate the extent of the resulting losses. The inability of instruments to distinguish between the risk of common but less serious harms and comparatively rare catastrophic events is a particular limitation of the value of risk categorisations. We should admit that our ability to assess risk is severely limited, and make clinical decisions in a similar way to those in other areas of medicine – by informed consideration of the potential consequences of treatment and non-treatment.

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Copyright
This is an Open Access article, distributed under the terms of the Creative Commons Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.
Corresponding author
Matthew M. Large (mmbl@bigpond.com)
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Declaration of interest

None.

Footnotes
References
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1 Weisman, RL, Lamberti, JS. Violence prevention and safety training for case management services. Community Ment Health J 2002; 38: 339–48.
2 New South Wales Health. Framework for Suicide Risk Assessment and Management for NSW Health Staff. New South Wales Health, 2005 (http://www.health.nsw.gov.au/pubs/2005/suicide_risk.html).
3 Royal College of Psychiatrists Special Working Party on Clinical Assessment and Management of Risk. Assessment and Clinical Management of Risk of Harm to Other People (Council Report CR53). Royal College of Psychiatrists, 1996.
4 New Zealand Health. The Assessment and Management of People at Risk of Suicide. New Zealand Guidelines Group and Ministry of Health, 2003.
5 Anfang, SA, Appelbaum, PS. Civil commitment – the American experience. Isr J Psychiatry Relat Sci 2006; 43: 209–18.
6 Dressing, H, Salize, HJ. Compulsory admission of mentally ill patients in European Union Member States. Soc Psychiatry Psychiatr Epidemiol 2004; 39: 797803.
7 Large, MM, Nielssen, O, Ryan, CJ, Hayes, R. Mental health laws that require dangerousness for involuntary admission may delay the initial treatment of schizophrenia. Soc Psychiatry Psychiatr Epidemiol 2008; 43: 251–6.
8 Roaldset, JO, Hartvig, P, Bjorkly, S. V-RISK-10: validation of a screen for risk of violence after discharge from acute psychiatry. Eur Psychiatry 2011; 26: 8591.
9 Abderhalden, C, Needham, I, Dassen, T, Halfens, R, Haug, HJ, Fischer, JE. Structured risk assessment and violence in acute psychiatric wards: randomised controlled trial. Br J Psychiatry 2008; 193: 4450.
10 Steadman, HJ, Silver, E, Monahan, J, Appelbaum, PS, Robbins, PC, Mulvey, EP, et al. A classification tree approach to the development of actuarial violence risk assessment tools. Law Hum Behav 2000; 24: 83100.
11 Barry-Walsh, J, Daffern, M, Duncan, S, Ogloff, J. The prediction of imminent aggression in patients with mental illness and/or intellectual disability using the Dynamic Appraisal of Situational Aggression instrument. Australas Psychiatry 2009; 17: 493–6.
12 Carroll, A. Risk assessment and management in practice: the forensicare risk assessment and management exercise. Australas Psychiatry 2008; 16: 412–7.
13 Hendin, H, Al Jurdi, RK, Houck, PR, Hughes, S, Turner, JB. Role of intense affects in predicting short-term risk for suicidal behavior: a prospective study. J Nerv Ment Dis 2010; 198: 220–5.
14 Cooper, J, Kapur, N, Mackway-Jones, K. A comparison between clinicians' assessment and the Manchester Self-Harm Rule: a cohort study. Emerg Med J 2007; 24: 720–1.
15 Hockberger, RS, Rothstein, RJ. Assessment of suicide potential by nonpsychiatrists using the SAD PERSONS score. J Emerg Med 1988; 6: 99107.
16 Mossman, D. The imperfection of protection through detection and intervention. Lessons from three decades of research on the psychiatric assessment of violence risk. J Leg Med 2009; 30: 109–40.
17 Nilsson, T, Munthe, C, Gustavson, C, Forsman, A, Anckarsater, H. The precarious practice of forensic psychiatric risk assessments. Int J Law Psychiatry 2009; 32: 400–7.
18 Large, MM, Ryan, CJ, Singh, SP, Paton, MB, Nielssen, OB. The predictive value of risk categorisation in schizophrenia. Harv Rev Psychiatry 2011; 19: 2533.
19 Szmukler, G. Violence risk prediction in practice. Br J Psychiatry 2001; 178: 84–5.
20 Szmukler, G. Risk assessment: ‘numbers’ and ‘values’. Psychiatr Bull 2003; 27: 205–7.
21 Ryan, CJ. One flu over the cuckoo's nest: comparing legislated coercive treatment for mental illness with that for other illness. J Bioeth Inq 2011; 8: 8793.
22 Large, MM, Ryan, CJ, Nielssen, OB, Hayes, RA. The danger of dangerousness: why we must remove the dangerousness criterion from our mental health acts. J Med Ethics 2008; 34: 877–81.
23 Mossman, D. Critique of Pure Risk Assessment or, Kant Meets Tarasoff. University of Cincinnati Law Rev 2006; 75: 523609.
24 Langan, J. Challenging assumptions about risk factors and the role of screening for violence risk in the field of mental health. Health Risk Soc 2010; 12: 85100.
25 Vickers, AJ, Altman, DG. Statistics notes: analysing controlled trials with baseline and follow up measurements. BMJ 2001; 323: 1123–4.
26 Kling, RN, Yassi, A, Smailes, E, Lovato, CY, Koehoorn, M. Evaluation of a violence risk assessment system (the alert system) for reducing violence in an acute hospital: a before and after study. Int J Nurs Stud 2011; 48: 534–9.
27 Moore, B (ed). The Australian Pocket Oxford Dictionary, Fifth Edition. Oxford University Press, 2003.
28 Hald, A, de Moivre, A. ‘De Mensura Sortis’ or ‘On the Measurement of Chance’. Int Stat Rev 1984; 52: 229–62.
29 Hacking, I. The Emergence of Probability: A Philosophical Study of Early Ideas about Probablity, Induction and Statistical Inference. Cambridge University Press, 1975.
30 Arnauld, A, Nicole, P. The Art of Thinking: Port-Royal Logic (trans J Dickoff & P James; original work published 1662). Bobbs-Merrill, 1964.
31 de Moivre, A. On the measurement of chance, or, on the probability of events in games depending on fortuitous chance (trans B McClintock; original work published 1711). Int Stat Rev 1984; 52: 229–62.
32 Bernstein, PL. Against the Gods: The Remarkable Story of Risk. John Wiley and Sons, 1996.
33 Anon. Risk Assessment. Wikipedia, 2010 (http://en.wikipedia.org/wiki/Risk_assessment).
34 Ryan, CJ, Nielssen, O, Paton, MB, Large, M. Clinical decisions in psychiatry should not be based on risk-assessment. Australas Psychiatry 2010; 18: 398403.
35 Anfang, SA, Appelbaum, PS. Twenty years after Tarasoff: reviewing the duty to protect. Harv Rev Psychiatry 1996; 4: 6776.
36 Steadman, HJ. Predicting dangerousness among the mentally ill: art, magic and science. Int J Law Psychiatry 1983; 6: 381–90.
37 Meehl, PE. Causes and effects of my disturbing little book. J Pers Assess 1986; 50: 370–5.
38 Buchanan, A. Risk of violence by psychiatric patients: beyond the “actuarial versus clinical” assessment debate. Psychiatr Serv 2008; 59: 184–90.
39 Kahneman, D, Tversky, A. Prospect theory: an analysis of decision under risk. Econometrica 1979; 47: 263–92.
40 Nielssen, O, Bourget, D, Laajasalo, T, Liem, M, Labelle, A, Häkkänen-Nyholm, H, et al. Homicide of strangers by people with a psychotic illness. Schizophr Bull 2011; 37: 572–9.
41 LeBourgeois, HW 3rd, Pinals, DA, Williams, V, Appelbaum, PS. Hindsight bias among psychiatrists. J Am Acad Psychiatry Law 2007; 35: 6773.
42 Green, DM, Swets, JM. Signal Detection Theory and the Psychophysics. John Wiley and Sons, 1966.
43 Nielssen, O, Large, M. Rates of homicide during the first episode of psychosis and after treatment: a systematic review and meta-analysis. Schizophr Bull 2010; 36: 702–12.
44 Large, M, Nielssen, O. Violence in first-episode psychosis: a systematic review and meta-analysis. Schizophr Res 2010; 125: 209–20.
45 Large, M, Smith, G, Sharma, S, Nielssen, O, Singh, S. Systematic review and meta-analysis of the clinical factors associated with the suicide of psychiatric in-patients. Acta Psychiatr Scand 2011; 124: 1829.
46 Harris, AW, Large, MM, Redoblado-Hodge, A, Nielssen, O, Anderson, J, Brennan, J. Clinical and cognitive associations with aggression in the first episode of psychosis. Aust N Z J Psychiatry 2010; 44: 8593.
47 Milton, J, Amin, S, Singh, SP, Harrison, G, Jones, P, Croudace, T, et al. Aggressive incidents in first-episode psychosis. Br J Psychiatry 2001; 178: 433–40.
48 Fazel, S, Lichtenstein, P, Grann, M, Goodwin, GM, Långström, N. Bipolar disorder and violent crime: new evidence from population-based longitudinal studies and systematic review. Arch Gen Psychiatry 2010; 67: 931–8.
49 Nielssen, O, Yee, N, Millard, M, Large, M. Comparison of first-episode and previously treated persons with psychosis found NGMI for a violent offense. Psychiatr Serv 2011; 62: 759–64.
50 Monahan, J, Steadman, H, Silver, E. The MacArthur Study of Mental Disorder and Violence. Oxford University Press, 2001.
51 Pokorny, AD. Prediction of suicide in psychiatric patients. Report of a prospective study. Arch Gen Psychiatry 1983; 40: 249–57.
52 Snowden, RJ, Gray, NS, Taylor, J, Fitzgerald, S. Assessing risk of future violence among forensic psychiatric inpatients with the Classification of Violence Risk (COVR). Psychiatr Serv 2009; 60: 1522–6.
53 Ritchie, J. The Report of the Inquiry into the Care and Treatment of Christopher Clunis. HMSO, 1994.
54 Roaldset, JO, Bjorkly, S. Patients' own statements of their future risk for violent and self-harm behaviour: a prospective inpatient and post-discharge follow-up study in an acute psychiatric unit. Psychiatry Res 2010; 178: 153–9.
55 Dawson, J, Szmukler, G. Fusion of mental health and incapacity legislation. Br J Psychiatry 2006; 188: 504–9.
56 Owen, GS, David, AS, Hayward, P, Richardson, G, Szmukler, G, Hotopf, M. Retrospective views of psychiatric in-patients regaining mental capacity. Br J Psychiatry 2009; 195: 403–7.
57 Okai, D, Owen, G, McGuire, H, Singh, S, Churchill, R, Hotopf, M. Mental capacity in psychiatric patients. Systematic review. Br J Psychiatry 2007; 191: 291–7.
58 Henderson, C, Flood, C, Leese, M, Thornicroft, G, Sutherby, K, Szmukler, G. Effect of joint crisis plans on use of compulsory treatment in psychiatry: single blind randomised controlled trial. BMJ 2004; 329: 136.
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Probability and loss: two sides of the risk assessment coin

  • Matthew M. Large (a1) and Olav B. Nielssen (a2)
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Re:Response to Large and Nielssen: Probabilty and Loss

Gordon R.W. Davies, Clinical Associate Professor
19 December 2011

The review of risk assessment by Large and Nielssen(1) is timely as there has been an increasing tendency to rely on structured protocols in the assessment of patients particularly with regard to future probabilities of violence and self harm.However there are a number of important aspects which have not been discussed, the most important of these being the concept of acceptable risk. Although politicians and service managers are happy to point to a process of risk assessment, they universally abrogate their duty as representatives of the community to define what level of risk is acceptable.Despite the statistical difficulties discussed this has been successfully embraced as a concept in aviation medicine. Acceptable failure rates in mechanical components have been used to define the risk management for pilot incapacitation. This approach was pioneered by cardiologists but the principle has been more widely adopted in aviation medicine, even though the definition of base rates of risk in other areas is not as straightforward (2).The acceptance of a defined level of risk has important implications for services. As an example if a patient is considered as being at risk of suicide, rather that the accepted risk being progressively increased as the bed availability declines, the service should have an obligation to provide a bed for those whose risk is considered greater than the acceptable level.Other common areas where risk assessments are required are release of potentially violent individuals from hospital or prison, safety in driving, the ability to own a firearm and suitability for employment in sensitive areas. When these assessments are made it is important that there is not only an understanding of the predictive value of such assessments but that there should be some idea of the relative and absolute risk considered acceptable by the community.Once this is defined then it automatically follows that an adverse result does not imply error. It is important that the community representatives, including coroners and politicians as well as then media, should be educated about this. Ultimately a decision about acceptable risk levels must be explicitly made by the community in advance with regard to their cost benefit ratio. Post hoc assessments of individual decisions are generally unhelpful.In providing reports involving risk assessment I always provide a comment in a report stating that while I have made my own evaluation that I would reconsider my assessment on the basis of a defined acceptable level of risk.Finally I would not agree with Large and Nielssen that risk assessment protocols should not be used. Their importance is not that they produce a usable rating (and I would note that these are strictly ordinal rather than interval scales) but that they do document that appropriate risk factors have been considered in the clinical decisions made.1.Large, M. M. & Nielssen, O.B. Prabability and loss: two sides of the risk assessment coin. The Psychiatrist 2011, 35 (11), 413-4182.Davies GRW, Psychiatry and Fitness for Flying, Practice, Evidence and Principles, Current Psychiatry Reviews, 2010, 6(1), 21-27 ... More

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Response to Large and Nielssen: Probabilty and Loss

Nick J. O'Connor, Clinical Director
07 December 2011

Large and Nielssen's recent article on the predictive value of risk categorisation in schizophrenia is an elegantly written and sobering analysis on clinical risk assessment practices [1]. Their arguments that risk categorisation approaches are limited and may sometimes do more harm than good are reminders of the limitations of the risk management approach. Theimperfect nature of risk categorisation is compellingly demonstrated by application of their HIRC model, applied to the best data available and ina manner that is, if anything, giving risk categorisation the fairest of road tests.Clinical risk assessments, be they based on clinical expertise, structured clinical assessment or actuarial tools are limited because of the mathematics of low frequency events.In probability and loss: two sides of the risk assessment coin[2]. Large and Nielssen advance their concerns about the current practice of risk management by examining the loss element of the risk assessment equation and the current limitation of any instrument to allow for multiplication of the sundry risks that may occur in the course of an unfolding episode of mental illness. They also point out, quite correctly, that clinicians are often operating on limited information. Our own experience with poor handover of all the available clinically important information (from referring clinicians, and family, or medical records stored in another facility) reminds us that even if we had the perfect tool, the risk assessment will only be as good as the information used will allow.These papers will be disconcerting for many clinicians and managers. The changeability of risk and elements of uncertainty in the human interactionof the assessment are other limitations[3]. Added to this is the nature ofthe task of assessing a person whose illness, personality or state of mindmay be constraints to accurate assessment. People may conceal information or their true feelings for a variety of reasons.These arguments against a risk assessment approach to managing clinical risk are important in ensuring against complacency and provide impetus forcontinuing development and refinement of our clinical practice. However, we need also to acknowledge that this is a discussion which is inevitably grounded in a number of frameworks other than the statistical. Large and Nielssen have not made reference to the moral, legal, ethical, cultural, political, compassionate and most importantly pragmatic frames of reference that support continuing to practise a risk assessment approach. While Large and Nielssen's approach is welcome in the arena of scientific discussion, it does not wash in the real world. Winston Churchill famouslyespoused the view that democracy "is the worst form of government except all those others that have been tried". So it is with risk assessment in our current time. The risk management approach when undertaken properly includes participation from a number of stakeholders including the patient, family,and health professionals in efforts to reduce or mitigate risk factors that are drawn from larger population studies, from information available in the clinical encounter and from collateral sources. Assessing risk is atask inherent in psychiatric assessment, and its' importance lies less in the assignation of a category of risk (high, low) than in the way the risks identified inform a treatment or management plan. The plan will ideally include the set of indicated interventions, delivered within an expected timeframe, that are considered best to manage and reduce the risks. There will always be uncertainty whether any risk will eventuate, even for those thought to have a high level of risk. As Large and Nielssenpoint out, this will leave a larger number of people who are judged as lowrisk with no intervention (above standard care), some of whom will turn out to have an adverse event. We are well served if this discussion reminds clinicians, patients and families that we have no perfect powers of prediction and draws the attention of researchers and clinical experts to reach for the next innovation to our methods."The essence of risk management lies in maximising the areas where we havesome control over the outcome while minimising the areas where we have absolutely no control over the outcome and the linkage between effect and cause is hidden from us." (ref)[4]

1.Large M M Ryan C J Singh S P Paton M B Nielssen O B, The predictive value of risk categorisation in schizophrenia. Harvard Review of Psychiatry 2011. 19(1): p. 25-33.2.Large M M Nielssen O B, Probability and Loss: two sides of the risk assessment coin. The Psychiatrist Online 2011. 35: p. 413-18.3.O'Connor N Warby M Rahael B Vassallo T, Changeability, confidence, common sense and corroboration: comprehensive suicide risk assessment. . Australasian Psychiatry, 2004. 12(2): p. 352- 360.4.Bernstein P, Against the Gods: The Remarkable Story of Risk. 1996, New York: John Wiley & Sons.

Dr Nick O'Connor and Assoc. Prof. Scott Clark

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