/nternetional Journal Pnnted I” the U.S.A.
of Law and Psychiatry. All rights reserved.
Vol. 13, 207-215.
1990 CopyrIght
0160.2527190 $3.00 + .OO a 1990 Pwgamon Press plc
Accounting for Predictions of Dangerousness Nathan L. Pollock*
Over the past two decades, there have been numerous attempts to develop clinical instruments and techniques for the prediction of dangerous behaviour (e.g., Carroll & Fuller, 1971; Hellman & Blackman, 1966; Holcomb & Adams, 1985; Lothstein & Jones, 1978; Megargee, Cook, & Mendelsohn, 1967; Menzies, Webster, & Sepejak, 1985; Syverson & Romney, 1985). The search for valid standardized scales, test batteries, diagnostic categories, and other clinical predictors continues despite meagre returns and growing doubt that the ambition of refining a predictive technology is at all worthwhile (Meehl, 1986; Megargee, 1970; Monahan, 1984). Unfortunately, much of the existing clinical research literature, dedicated as it is to the development of a technology of prediction, underestimates the complexities of actual clinical procedures. Clinicians, already handicapped by imprecise tools, find themselves further encumbered by the lack of substantive discussion about how, given the limits of their abilities, they can responsibly conduct assessments of dangerousness. The search for accurate predictors of dangerousness has its roots in the historical interdependence of psychiatry and the law. According to Foucault (1978), by the latter part of the 19th century, it was apparent that the penal system was unable to achieve the ideal of reforming the criminal. The emphasis of the criminal justice system began to shift from a focus on legal responsibility and rehabilitation, to the issue of protection for society. With this shift in focus, the demands on mental health professionals in the judicial system also began to change. Whereas previously, clinicians were called upon primarily for explanations of criminal behaviour and recommendations for treatment, now they were being asked to offer predictions as well. By the beginning of the 20th century the concept of the “dangerous being” (Petrunik, 1983) had become an established concept in criminal law and psychiatry. It attained this status not on scientific grounds but because it served legal imperatives. Clinicians in the justice system had assumed a role shaped more by judicial priorities than by a realistic appraisal of what mental health professionals could reasonably offer the legal process. As a result, the function of clinicians assessing dangerousness had grown increasingly narrow and in many quarters had come to be regarded as having a single purpose-accurate prediction. As Halleck (1987) has aptly remarked, clinicians
*Clarke
Institute
of Psychiatry,
250 College St., Toronto, 207
Ontario,
MST lR8, Canada.
208
NATHAN L. POLLOCK
can play the important role of telling decisionmakers more about the social situations and the biological and psychological incapacities of the individuals who are the subject of their decisions. Alas, that rarely happens . . . Rather we get put into the role . . . of the Wizard, a role with many perils. (p.87) Along similar lines, Marra, Konzelman, and Giles (1987) have observed that forensic clinicians are often caught between the limitations of their ability to predict violent behaviour and the growing demand from the courts to assist in the identification of dangerous individuals. Given these difficult and sometimes perilous circumstances, they argue, clinicians must adopt scientifically defensible, clinical decision-making strategies. They advocate a clinical strategy for the assessment of dangerousness based on a conceptually valid decision-making model. From this perspective, despite an imprecise predictive technology, clinicians can and should be accountable for their decisions about dangerousness. The following case history illustrates this critical distinction between predictive accuracy and clinical accountability. About six years ago, as part of a multi-disciplinary team on the Forensic Service of the Clarke Institute of Psychiatry, I was involved in the assessment of a 17 year old youth who was facing a charge of possession of volatile and explosive substances. He had been arrested after igniting a model rocket engine at a school dance. The police searched his home and found a pipe bomb and books on how to construct explosive devices. What particularly concerned the police was the young man’s offhand remark that his ambition in life was to blow himself up and take a city block with him. The court wanted to know if he was as dangerous as the police suspected. His background and clinical presentation were no different than many other adolescent property offenders seen on the Forensic Service. He described feelings of alienation from his family and peers. He had a history of school adjustment problems including truancy and insubordination. By age 15 he had dropped out of school, was using drugs and alcohol on a regular basis and had a substantial criminal record including convictions for break and enter, theft, mischief to private property, and drinking under age. At age 16 he was convicted of five counts of break and enter and possession of stolen property. At the time of the explosives charge he was still on probation for these offences. He had no history of violent behaviour, no prior psychiatric treatment, and he denied any emotional or psychological problems. Clinical examination revealed no evidence of psychotic symptoms. Neurological investigations were negative. No physical abnormalities were detected. Psychological testing indicated High Average intelligence and antisocial personality features. He received a psychiatric diagnosis of Conduct Disorder. He went to trial and our report to the court was submitted as evidence. In it we stated “we do not feel that this young man will be a
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danger to society.” He was given probation on the explosives charge. Six months later he was arrested for the brutal murder of a 16 year old boy. He and a friend had bludgeoned and kicked the boy to death because they believed he had informed the police about a theft one of them had committed. They froze the body in a basement freezer and later dismembered the corpse and hid the body parts in a nearby field. The young man was eventually found guilty of second degree murder and sentenced to life imprisonment with no parole for 18 years. A newspaper article covering the sentencing proceedings at the murder trial read “The Clarke report, penned just six months before the murder, said in heavily underlined words that Mr. A. was ‘not a danger to society”‘. The judge was quoted as saying that the Clarke report was “written without any reference to realities.” The article went on to say that a second psychiatric report written at the time of the explosives charge found that, “He is potentially dangerous to others at this time.” In this case two independent clinical assessments reached radically different conclusions about the potential for dangerous behaviour. Which of these opinions was correct? This may seem like a foolish question, knowing the outcome of the case, but I think it highlights an important issue. From the perspective of predictive accuracy the second psychiatric opinion was clearly the better of the two. From another perspective, however, that of clinical accountability, a prediction of dangerousness in this case was simply indefensible. As Kozol (1982) has remarked, “no one can predict criminally dangerous behaviour in an individual with no history of dangerous acting out” (p. 255). From this standpoint, the only correct statement about the young man’s potential for dangerousness would have been that no scientifically defensible prediction could be offered. Despite the judge’s opinion of the Clarke report, the realities of the case were such that no clinician could have reasonably predicted that this young man was soon to commit murder. Given the inability to accurately predict dangerous behaviour in cases such as these, how should clinicians proceed? This is a contentious issue. Some authorities (e.g., Stone, 1985) have argued that clinicians should refuse entirely to participate in legal deliberations about dangerousness, while others (e.g., Dietz, 1985) believe a substantial contribution can be made. Among those who advocate the participation of clinicians in predictive decision making, there is further disagreement about appropriate methods. Some argue that an actuarial approach is, in general, the more accurate procedure (e.g., Gottfredson, 1987) while others espouse an idiographic clinical approach, believing it to be more thorough and adaptable (e.g., Halleck, 1987; Holt, 1978). Clinical precision and predictive accuracy, however, are not the only issues to consider. Monahan and Wexler (1978) have made the point that predictions of dangerousness need not be unerring to serve a useful purpose, provided both the courts and clinicians are aware of the legal and clinical realities. Monahan (1984) has convincingly argued that society has a right to expect experts in human behaviour, despite their imperfect knowledge, to perform a limited social control function when it comes to violence prevention. Similarly, Kozol
210
NATHAN L. POLLOCK
(1982) has asserted that when it comes to assessing dangerous potential “the profession of psychiatry has a responsibility to assist in the administration of justice sincerely and without reservation or equivocation” (p. 244). When the prediction of dangerousness, despite its imperfections, is seen as a social responsibility, accountability necessarily becomes a principal consideration for clinicians. To be scientifically defensible a prediction of dangerousness must derive from a theoretically sound decision-making model. Based on such a model the skilled clinician can formulate and test clinical hypotheses to delineate characteristic patterns of violence in the individual. Once defined, these patterns can be extrapolated for predictive purposes. As Mulvey and Lidz (1984) have observed, “Noting when a constellation of disruptive or aggressive behaviors began can be a useful indicator of the likely persistence of those behaviors” (p. 396). In each case, the clinician may formulate different hypotheses, employ different instruments, and describe different patterns of violence. To ensure accountability, however, every assessment must be guided by a clinical decision-making model which can withstand scientific scrutiny (Pollock, McBain, & Webster, 1989). As Marra, Konzelman, and Giles (1987), have remarked “clinicians can function within professional and ethical parameters in dealing with issues of dangerousness if their conclusions are founded in an approach and strategy that allows for a critical evaluation of the internal consistency of the data base through conceptual validation” (p. 299). Where does this emphasis on accountability leave the technology of prediction? This depends primarily on how the technology is applied. Clinical measures, predictors, and indicators may help prove or disprove a clinical hypothesis but no combination of instruments, scales, or tests is definitive or even relevant in every case. Given the complexity of the task, this is perhaps not difficult to understand. Violence is not a unitary construct. Different people act violently for different reasons. A clinical device for assessing dangerousness would require a very large number of items, not all of which would be applicable in a given case and these items would probably have to be weighted differently according to the facts of the case under consideration (Bern & Allen, 1974; Bern & Funder, 1978). Simply administering a large battery of tests or conducting a wide-ranging interview in the hope of identifying clinical indicators of dangerousness, is not a scientifically defensible procedure. Among researchers it is well understood that by increasing the number of dependent variables under consideration an experimenter increases the probability of spurious significant findings. Similarly, if the clinician indiscriminately applies every available clinical measure, the chances of finding an apparent predictor of dangerousness become very high. Unless the measures are selected to evaluate clinical hypotheses derived from a scientifically defensible decision-making strategy, the clinician runs the risk of seriously misjudging the causes and likelihood of dangerous behaviour. Quinsey and Maguire (1986) have stressed the importance of using theoretically relevant measures in the prediction of dangerousness. They argue that “Research efforts in the future must be guided by theories that specify which sorts of variables should be related to certain sorts of outcomes in specific postrelease conditions” (p. 169). While psychometric instruments, specialized
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medical tests, and other clinical procedures can be of considerable value in evaluating factors which may contribute to violence, without a theoretically sound clinical decision-making strategy, these techniques have little to offer the prediction of dangerousness. A few basic principles of prediction can be used to illustrate a defensible clinical decision-making approach. One fundamental tenet of predicting dangerousness is that violent behaviour cannot be predicted in the absence of an established pattern of violence (Hall, 1987; Kozol, 1982). This makes sense from a statistical point of view, because the chances of accurately predicting violence in an individual who has never been violent are simply too remote. The probability of accurate prediction under these conditions is equal to the base rate of violence in the general population, about 1 in 400 in the United States (Hall, 1987). This basic principle also makes sense from a clinical perspective. Because clinical predictions of dangerousness are based on extrapolations of clearly defined patterns of violence in the individual’s past, in the absence of prior violence no predictions can be formulated. Another widely cited principle of predicting dangerousness is that predictions must take into account the complex interaction of individual characteristics and environmental variables contributing to violent behaviour (Megargee, 1976; Menzies et al., 1985; Mulvey & Lidz, 1984). In some instances, the individual’s personality and socialization experiences might be primarily responsible for a failure to counteract violent impulses, while in other circumstances situational factors such as the termination of a central love relationship, a sudden worsening of financial status, or a family crisis may predominate (Hall, 1984). Nonetheless, in every case, to a greater or lesser extent, the interplay of psychological and situational variables must be considered. A third basic principle of predicting dangerousness is that violence is often the result of an imbalance between predisposing and countervailing factors (Hall, 1987). Whether or not a person behaves violently depends on their ability to regulate and control violent tendencies and to adapt to environment demands. When the person’s self-regulatory and adaptive mechanisms are disrupted, behaviour can become erratic, poorly controlled, and possibly destructive. This may happen, for example, with intoxication or under extreme and unusual stress (Megargee, 1976). Hall (1984) refers to such disinhibiting influences as “triggering stimuli.” In predicting dangerousness, it is important to note whether acts of violence in the past have been associated with periods of disorganization and disinhibition. Brain damage, severe depression, psychotic decompensation, and substance abuse should be investigated as possible disruptive factors. Simple principles such as these can guide clinicians’ decisions in formulating preliminary hypotheses. Sometimes this may happen through a process of elimination. Consider, for example, an offender with a history of premeditated sexual violence. In the absence of evidence linking the violent behaviour with situational or disinhibitory factors, a clinician assessing this individual might reasonably infer that his behaviour is attributable to predisposing personality factors such as hostility, an antisocial orientation, or sadistic tendencies. These possibilities can then be investigated with clinical interviews, psychological assessment, or specialized sexual preference testing (Freund, 1976). Depending
212
NATHAN L. POLLOCK
on the findings the initial hypotheses can be accepted or rejected and other hypotheses may be formulated and tested. Often the evidence is more direct, for example, when there is an obvious pattern of violence associated with psychological disorganization. In such cases, a defensible argument can be made for a continuing potential for violent behaviour as long as the risk of future disorganization is high. For instance, if a particular individual behaves violently only when intoxicated or only during psychotic episodes and if the likelihood of continuing alcohol abuse or psychotic decompensation can be estimated, then something useful can be concluded about the probability of future violence. Consider the following case: A 25-year-old college student was admitted to the forensic unit of a psychiatric hospital after severely beating his maternal grandmother. The patient was living in the family home at the time of the assault. In interview he insisted that his grandmother had been conspiring with other family members to manipulate him into marrying a young woman he had once known in high school. He maintained that she had persisted in her efforts despite his protests and finally he felt compelled to attack her. The patient had no prior criminal convictions. On a previous occasion, however, he had assaulted his mother under similar circumstances. Following the assault on his mother, he had been hospitalized and diagnosed as paranoid schizophrenic. He responded well to medication and after several weeks was able to realize that he had misperceived his mother’s intentions. At discharge the patient was strongly encouraged to establish a more independent life outside the family home. He was offered life skills counselling and assistance in establishing independent accommodations, employment, and social supports. Instead, he opted to return home and soon after stopped taking his medication. A short time later he attacked his father and had to be readmitted to hospital. This second admission followed a course similar to the first with the patient ultimately returning home and assaulting his grandmother. In this case there is a clear connection between psychotic decompensation and violent behaviour. The clinician assessing this young man might hypothesize that his violent behaviour was in large part attributable to the disorganizing effects of a psychotic episode possibly influenced by family stress. The repetitive nature of violent behaviour directed at family members and associated with paranoid delusions suggests a well defined pattern. Investigations to confirm the clinical hypothesis might include psychometric testing to establish evidence of psychotic process, a psychiatric consultation for diagnostic clarification, and a social work assessment to evaluate family dynamics. If the hypothesis was confirmed, the clinician in this situation could state with considerable confidence that, should a psychotic episode recur while the patient was still living with his family, the risk of violence would be high. The history of poor medication compliance and the patient’s continued dependence on his family would further increase the probability of recurring psychotic episodes and future assaults.
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This example is particularly instructive because it illustrates the shortcomings of an atheoretical, actuarial approach to prediction. In this case, the clinical conclusions, linking psychosis with violence, are only defensible from a theoretical standpoint. A purely statistical approach might have neglected the influence of this young man’s psychiatric disturbance on his behaviour because, in general, mental illness has not been found to be predictive of dangerous behaviour (Monahan, 1981; Mulvey & Lidz, 1984; Rabkin, 1979). A theoretically based decision-making strategy can often help clinicians choose between clinical and actuarial approaches. Simply put, actuarial methods are likely to prove superior whenever predictive clinical hypotheses cannot be readily formulated or tested. This is usually so when dangerous behaviour does not show a clear pattern of association with situational or disinhibitory factors. Under these circumstances, when violence seems primarily attributable to personality features, cause and effect relationships between precipitating factors and violent actions are difficult to establish. Although personality traits such as impulsivity, hostility, aggressiveness, and antisocial orientation may have explanatory relevance (Pollock et al., 1989), there is little empirical support for their utility in predicting actual occurrences of aggressive behaviour. We simply do not yet have the necessary theoretical and technological sophistication to make reliable clinical predictions based on personality assessment alone (Goldstein & Keller, 1987; Meehl, 1986). As Kozol (1982) has remarked, “dangerous potential is not detectable through routine psychiatric examination. Nor is it detectable by any single test or combination of stereotyped tests” (p. 254). Clinical methods are most often appropriate when disinhibitory or situational factors are clearly implicated. This is largely because disinhibited behaviour and situational influences are easier to observe than personality traits and can often be evaluated and monitored with some precision. Whereas the clinician can never be certain of t,he individual’s psychological state at the time of a violent act, information about alcohol intoxication, psychotic decompensation, provocation, financial pressures, etc., is frequently available through family members, eye witness accounts, institutional records, and police reports. In conclusion, clinicians confronted with the responsibility of predicting dangerous behaviour but equipped with an imperfect technology, face a difficult challenge. Because of the longstanding emphasis on technical advancement and predictive accuracy, the scientific literature has made little progress toward the development of defensible clinical approaches to prediction. There is a need for theoretically based decision-making strategies to help clinicians judge when predictions of dangerousness are warranted, when they are possible, which methods to employ, which data to collect and how the data can be synthesized to arrive at defensible statements about dangerousness. By relying on scientifically sound, decision-making models clinicians can ensure accountability while maintaining a balance between scientific integrity and social responsibility.
References Bern, D., & Allen, A. (1974). On predicting some of the people some of the time: The search situational consistencies in behaviour. Psychological Review, 81, 506-520.
for cross-
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Bern, D., & Funder, D. (1978). Predicting more of the people more of the time: Assessing the personality of situations. Psychological Review, 85, 485-501. Carroll, J. L., & Fuller, G. B. (1971). An MMPI comparison of three groups of criminals. Journal of Clinical Psychology, 27, 240-242. Dietz, P. E. (1985). Hypothetical criteria for the prediction of individual criminality. In C. D. Webster, M. H. Ben-Aron, & S. J. Hucker (Eds.), Dangerousness: Probability andprediction. psychiarrv and public policy (pp. 87-102). New York: Cambridge University Press. Foucault, M. (1978). About the concept of the “dangerous individual” in 19th century legal psychiatry. International Journal of Law and Psychiatry, I, l-19. Freund, K. (1976). Diagnosis and treatment of forensically significant anomalous erotic preferences. Cnnadion Journal of Criminology & Corrections, I&3), 181-l 89. Goldstein, A. P, & Keller, H. (1987). Aggressive behavior: Assessment and infervenfion. Elmsford. NY Pergamon Press. Gottfredson, S. D. (1975). Statistical and actuarial considerations. In F. N. Dutile, & C. D. Foust, (Eds.), The prediction ofcriminal violence (pp. 71-81). Springfield, IL: Charles C Thomas. Hall, H. V. (1984). Predicting dangerousness for the courts. American Journal ofForensic Psychology, 4, 525. Hall, H. V. (1987). Violence prediction. Guidelinesfor theforensic prucfirioner. Springfield, IL: Charles C Thomas. Halleck, S. (1987). Clinical applicability for prediction. In F. N. Dutile, &C. D. Faust (Eds.), The prediction of criminal violence (pp. 83-88). Springfield, IL: Charles C Thomas. Hellman, D. S., & Blackman, N. (1966). Enuresis, firesetting, and cruelty to animals: A triad predictive of adult crime. American Journal ofPsychiatry, 122, 1431-1435. Holcomb, W. R., & Adams, N. A. (1985). Personality mechanisms of alcohol-related violence. Journal of Clinical Psychology, 41,714-722. Holt, R. R. (1978). Methods in clinicalpsychology: Predicfion ond research: Vol2. New York: Plenum Press. Kozol, H. L. (1982). Dangerousness in society and law. The University of Toledo Low Review, 13, 241-267. Lothstein, L. M., & Jones, P. (1978). Discriminating violent individuals by means of various psychological tests. Journal of Personality Assessment, 42, 237-224. Marra, A. M., Konzelman, Cl. E., & Giles, P. G. (1987). A clinical strategy to the assessment of dangerousness. Inlernational Journal of Offender Therapy and Comparative Criminology, 31. 291-299. Meehl, P. E. (1986). Causes and effects of my disturbing little book. Journal of Personality Assessment, 50, 370-375. Megargee, E. I. (1970). The prediction of violence with psychological tests. In C. Spielberg (Ed.), Currenr topics in clinical and community psychology (pp. 98- 156). New York: Academic Press. Megargee, E. I. (1976). The prediction of dangerous behavior. Criminal Jusfice and Behavior, 3, 3-22. Megargee, E. I., Cook, P. E., & Mendelsohn, G. A. (1967). Development and validation of an MMPI scale of assaultiveness in over-controlled individuals. Journal ofAbnormal Psychology, 72, 5 19-528. Menzies, R. J., Webster, C. D., & Sepejak, D. S. (1985). The dimensions of dangerousness: Evaluating the accuracy of psychometric predictions of violence among forensic patients. Law and Human Behoviour, 9, 35-56. Monahan, J. (1981). Predicting violent behavior: An assessment of clinical techniques. Beverly Hills, CA: Sage. Monahan, J. (1984). The prediction of violent behavior: Toward a second generation of theory and policy. American Journal of Psychiatry, 141, IO- 15. Monahan, J., & Wexler, D. B. (1978). A definite maybe: Proof and probability in civil commitment. Luwond Human Behavior, 2, 37-42. Mulvey, E. P., & Lidz, C. W. (1984). Clinical considerations in the prediction of dangerousness in mental patients. Clinical Psychology Review, 4, 379-401. Petrunik, M. (1983). The politics of dangerousness. International Journal of Low and Psychiatry, 5, 225246. Pollock, N., McBain, I., & Webster, C. D. (1989). Clinical decision making and the assessment of dangerousness. In K. Howells & C. Hollin (Eds.), Clinical approuches to uggression ond violence (pp. 89-115). Chichester: John Wiley. Quinsey, V., & Maguire, A. (1986). Maximum security psychiatric patients: Actuarial and clinical prediction of dangerousness. Journal of Inrerpersonal Violence, I, 143-17 I. Rabkin, J. G. (1979). Criminal behavior of discharged mental patients: A critical appraisal of the literature. Psychological Bulleiin, 86, I-27.
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Stone, A. A. (1985). The new legal standard of dangerousness: Fair in the theory, unfair in practice. In C. D. Webster, M. H. Ben-Aron, & S. J. Hucker (Eds.), Dangerousness: Probability and prediction, psychiarq andpublicpolicy (pp. 13-24). New York: Cambridge University Press. Syverson, K. L., & Romney, D. M. (1985). A further attempt to differentiate violent from nonviolent offenders by means of a battery of psychological tests. Canadian Journal of Behavioural Science, 17. 87-
92.
of Law and Psychiatry. All rights reserved.
Vol. 13, 207-215.
1990 CopyrIght
0160.2527190 $3.00 + .OO a 1990 Pwgamon Press plc
Accounting for Predictions of Dangerousness Nathan L. Pollock*
Over the past two decades, there have been numerous attempts to develop clinical instruments and techniques for the prediction of dangerous behaviour (e.g., Carroll & Fuller, 1971; Hellman & Blackman, 1966; Holcomb & Adams, 1985; Lothstein & Jones, 1978; Megargee, Cook, & Mendelsohn, 1967; Menzies, Webster, & Sepejak, 1985; Syverson & Romney, 1985). The search for valid standardized scales, test batteries, diagnostic categories, and other clinical predictors continues despite meagre returns and growing doubt that the ambition of refining a predictive technology is at all worthwhile (Meehl, 1986; Megargee, 1970; Monahan, 1984). Unfortunately, much of the existing clinical research literature, dedicated as it is to the development of a technology of prediction, underestimates the complexities of actual clinical procedures. Clinicians, already handicapped by imprecise tools, find themselves further encumbered by the lack of substantive discussion about how, given the limits of their abilities, they can responsibly conduct assessments of dangerousness. The search for accurate predictors of dangerousness has its roots in the historical interdependence of psychiatry and the law. According to Foucault (1978), by the latter part of the 19th century, it was apparent that the penal system was unable to achieve the ideal of reforming the criminal. The emphasis of the criminal justice system began to shift from a focus on legal responsibility and rehabilitation, to the issue of protection for society. With this shift in focus, the demands on mental health professionals in the judicial system also began to change. Whereas previously, clinicians were called upon primarily for explanations of criminal behaviour and recommendations for treatment, now they were being asked to offer predictions as well. By the beginning of the 20th century the concept of the “dangerous being” (Petrunik, 1983) had become an established concept in criminal law and psychiatry. It attained this status not on scientific grounds but because it served legal imperatives. Clinicians in the justice system had assumed a role shaped more by judicial priorities than by a realistic appraisal of what mental health professionals could reasonably offer the legal process. As a result, the function of clinicians assessing dangerousness had grown increasingly narrow and in many quarters had come to be regarded as having a single purpose-accurate prediction. As Halleck (1987) has aptly remarked, clinicians
*Clarke
Institute
of Psychiatry,
250 College St., Toronto, 207
Ontario,
MST lR8, Canada.
208
NATHAN L. POLLOCK
can play the important role of telling decisionmakers more about the social situations and the biological and psychological incapacities of the individuals who are the subject of their decisions. Alas, that rarely happens . . . Rather we get put into the role . . . of the Wizard, a role with many perils. (p.87) Along similar lines, Marra, Konzelman, and Giles (1987) have observed that forensic clinicians are often caught between the limitations of their ability to predict violent behaviour and the growing demand from the courts to assist in the identification of dangerous individuals. Given these difficult and sometimes perilous circumstances, they argue, clinicians must adopt scientifically defensible, clinical decision-making strategies. They advocate a clinical strategy for the assessment of dangerousness based on a conceptually valid decision-making model. From this perspective, despite an imprecise predictive technology, clinicians can and should be accountable for their decisions about dangerousness. The following case history illustrates this critical distinction between predictive accuracy and clinical accountability. About six years ago, as part of a multi-disciplinary team on the Forensic Service of the Clarke Institute of Psychiatry, I was involved in the assessment of a 17 year old youth who was facing a charge of possession of volatile and explosive substances. He had been arrested after igniting a model rocket engine at a school dance. The police searched his home and found a pipe bomb and books on how to construct explosive devices. What particularly concerned the police was the young man’s offhand remark that his ambition in life was to blow himself up and take a city block with him. The court wanted to know if he was as dangerous as the police suspected. His background and clinical presentation were no different than many other adolescent property offenders seen on the Forensic Service. He described feelings of alienation from his family and peers. He had a history of school adjustment problems including truancy and insubordination. By age 15 he had dropped out of school, was using drugs and alcohol on a regular basis and had a substantial criminal record including convictions for break and enter, theft, mischief to private property, and drinking under age. At age 16 he was convicted of five counts of break and enter and possession of stolen property. At the time of the explosives charge he was still on probation for these offences. He had no history of violent behaviour, no prior psychiatric treatment, and he denied any emotional or psychological problems. Clinical examination revealed no evidence of psychotic symptoms. Neurological investigations were negative. No physical abnormalities were detected. Psychological testing indicated High Average intelligence and antisocial personality features. He received a psychiatric diagnosis of Conduct Disorder. He went to trial and our report to the court was submitted as evidence. In it we stated “we do not feel that this young man will be a
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FOR PREDICTIONS
OF DANGEROUSNESS
209
danger to society.” He was given probation on the explosives charge. Six months later he was arrested for the brutal murder of a 16 year old boy. He and a friend had bludgeoned and kicked the boy to death because they believed he had informed the police about a theft one of them had committed. They froze the body in a basement freezer and later dismembered the corpse and hid the body parts in a nearby field. The young man was eventually found guilty of second degree murder and sentenced to life imprisonment with no parole for 18 years. A newspaper article covering the sentencing proceedings at the murder trial read “The Clarke report, penned just six months before the murder, said in heavily underlined words that Mr. A. was ‘not a danger to society”‘. The judge was quoted as saying that the Clarke report was “written without any reference to realities.” The article went on to say that a second psychiatric report written at the time of the explosives charge found that, “He is potentially dangerous to others at this time.” In this case two independent clinical assessments reached radically different conclusions about the potential for dangerous behaviour. Which of these opinions was correct? This may seem like a foolish question, knowing the outcome of the case, but I think it highlights an important issue. From the perspective of predictive accuracy the second psychiatric opinion was clearly the better of the two. From another perspective, however, that of clinical accountability, a prediction of dangerousness in this case was simply indefensible. As Kozol (1982) has remarked, “no one can predict criminally dangerous behaviour in an individual with no history of dangerous acting out” (p. 255). From this standpoint, the only correct statement about the young man’s potential for dangerousness would have been that no scientifically defensible prediction could be offered. Despite the judge’s opinion of the Clarke report, the realities of the case were such that no clinician could have reasonably predicted that this young man was soon to commit murder. Given the inability to accurately predict dangerous behaviour in cases such as these, how should clinicians proceed? This is a contentious issue. Some authorities (e.g., Stone, 1985) have argued that clinicians should refuse entirely to participate in legal deliberations about dangerousness, while others (e.g., Dietz, 1985) believe a substantial contribution can be made. Among those who advocate the participation of clinicians in predictive decision making, there is further disagreement about appropriate methods. Some argue that an actuarial approach is, in general, the more accurate procedure (e.g., Gottfredson, 1987) while others espouse an idiographic clinical approach, believing it to be more thorough and adaptable (e.g., Halleck, 1987; Holt, 1978). Clinical precision and predictive accuracy, however, are not the only issues to consider. Monahan and Wexler (1978) have made the point that predictions of dangerousness need not be unerring to serve a useful purpose, provided both the courts and clinicians are aware of the legal and clinical realities. Monahan (1984) has convincingly argued that society has a right to expect experts in human behaviour, despite their imperfect knowledge, to perform a limited social control function when it comes to violence prevention. Similarly, Kozol
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(1982) has asserted that when it comes to assessing dangerous potential “the profession of psychiatry has a responsibility to assist in the administration of justice sincerely and without reservation or equivocation” (p. 244). When the prediction of dangerousness, despite its imperfections, is seen as a social responsibility, accountability necessarily becomes a principal consideration for clinicians. To be scientifically defensible a prediction of dangerousness must derive from a theoretically sound decision-making model. Based on such a model the skilled clinician can formulate and test clinical hypotheses to delineate characteristic patterns of violence in the individual. Once defined, these patterns can be extrapolated for predictive purposes. As Mulvey and Lidz (1984) have observed, “Noting when a constellation of disruptive or aggressive behaviors began can be a useful indicator of the likely persistence of those behaviors” (p. 396). In each case, the clinician may formulate different hypotheses, employ different instruments, and describe different patterns of violence. To ensure accountability, however, every assessment must be guided by a clinical decision-making model which can withstand scientific scrutiny (Pollock, McBain, & Webster, 1989). As Marra, Konzelman, and Giles (1987), have remarked “clinicians can function within professional and ethical parameters in dealing with issues of dangerousness if their conclusions are founded in an approach and strategy that allows for a critical evaluation of the internal consistency of the data base through conceptual validation” (p. 299). Where does this emphasis on accountability leave the technology of prediction? This depends primarily on how the technology is applied. Clinical measures, predictors, and indicators may help prove or disprove a clinical hypothesis but no combination of instruments, scales, or tests is definitive or even relevant in every case. Given the complexity of the task, this is perhaps not difficult to understand. Violence is not a unitary construct. Different people act violently for different reasons. A clinical device for assessing dangerousness would require a very large number of items, not all of which would be applicable in a given case and these items would probably have to be weighted differently according to the facts of the case under consideration (Bern & Allen, 1974; Bern & Funder, 1978). Simply administering a large battery of tests or conducting a wide-ranging interview in the hope of identifying clinical indicators of dangerousness, is not a scientifically defensible procedure. Among researchers it is well understood that by increasing the number of dependent variables under consideration an experimenter increases the probability of spurious significant findings. Similarly, if the clinician indiscriminately applies every available clinical measure, the chances of finding an apparent predictor of dangerousness become very high. Unless the measures are selected to evaluate clinical hypotheses derived from a scientifically defensible decision-making strategy, the clinician runs the risk of seriously misjudging the causes and likelihood of dangerous behaviour. Quinsey and Maguire (1986) have stressed the importance of using theoretically relevant measures in the prediction of dangerousness. They argue that “Research efforts in the future must be guided by theories that specify which sorts of variables should be related to certain sorts of outcomes in specific postrelease conditions” (p. 169). While psychometric instruments, specialized
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medical tests, and other clinical procedures can be of considerable value in evaluating factors which may contribute to violence, without a theoretically sound clinical decision-making strategy, these techniques have little to offer the prediction of dangerousness. A few basic principles of prediction can be used to illustrate a defensible clinical decision-making approach. One fundamental tenet of predicting dangerousness is that violent behaviour cannot be predicted in the absence of an established pattern of violence (Hall, 1987; Kozol, 1982). This makes sense from a statistical point of view, because the chances of accurately predicting violence in an individual who has never been violent are simply too remote. The probability of accurate prediction under these conditions is equal to the base rate of violence in the general population, about 1 in 400 in the United States (Hall, 1987). This basic principle also makes sense from a clinical perspective. Because clinical predictions of dangerousness are based on extrapolations of clearly defined patterns of violence in the individual’s past, in the absence of prior violence no predictions can be formulated. Another widely cited principle of predicting dangerousness is that predictions must take into account the complex interaction of individual characteristics and environmental variables contributing to violent behaviour (Megargee, 1976; Menzies et al., 1985; Mulvey & Lidz, 1984). In some instances, the individual’s personality and socialization experiences might be primarily responsible for a failure to counteract violent impulses, while in other circumstances situational factors such as the termination of a central love relationship, a sudden worsening of financial status, or a family crisis may predominate (Hall, 1984). Nonetheless, in every case, to a greater or lesser extent, the interplay of psychological and situational variables must be considered. A third basic principle of predicting dangerousness is that violence is often the result of an imbalance between predisposing and countervailing factors (Hall, 1987). Whether or not a person behaves violently depends on their ability to regulate and control violent tendencies and to adapt to environment demands. When the person’s self-regulatory and adaptive mechanisms are disrupted, behaviour can become erratic, poorly controlled, and possibly destructive. This may happen, for example, with intoxication or under extreme and unusual stress (Megargee, 1976). Hall (1984) refers to such disinhibiting influences as “triggering stimuli.” In predicting dangerousness, it is important to note whether acts of violence in the past have been associated with periods of disorganization and disinhibition. Brain damage, severe depression, psychotic decompensation, and substance abuse should be investigated as possible disruptive factors. Simple principles such as these can guide clinicians’ decisions in formulating preliminary hypotheses. Sometimes this may happen through a process of elimination. Consider, for example, an offender with a history of premeditated sexual violence. In the absence of evidence linking the violent behaviour with situational or disinhibitory factors, a clinician assessing this individual might reasonably infer that his behaviour is attributable to predisposing personality factors such as hostility, an antisocial orientation, or sadistic tendencies. These possibilities can then be investigated with clinical interviews, psychological assessment, or specialized sexual preference testing (Freund, 1976). Depending
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on the findings the initial hypotheses can be accepted or rejected and other hypotheses may be formulated and tested. Often the evidence is more direct, for example, when there is an obvious pattern of violence associated with psychological disorganization. In such cases, a defensible argument can be made for a continuing potential for violent behaviour as long as the risk of future disorganization is high. For instance, if a particular individual behaves violently only when intoxicated or only during psychotic episodes and if the likelihood of continuing alcohol abuse or psychotic decompensation can be estimated, then something useful can be concluded about the probability of future violence. Consider the following case: A 25-year-old college student was admitted to the forensic unit of a psychiatric hospital after severely beating his maternal grandmother. The patient was living in the family home at the time of the assault. In interview he insisted that his grandmother had been conspiring with other family members to manipulate him into marrying a young woman he had once known in high school. He maintained that she had persisted in her efforts despite his protests and finally he felt compelled to attack her. The patient had no prior criminal convictions. On a previous occasion, however, he had assaulted his mother under similar circumstances. Following the assault on his mother, he had been hospitalized and diagnosed as paranoid schizophrenic. He responded well to medication and after several weeks was able to realize that he had misperceived his mother’s intentions. At discharge the patient was strongly encouraged to establish a more independent life outside the family home. He was offered life skills counselling and assistance in establishing independent accommodations, employment, and social supports. Instead, he opted to return home and soon after stopped taking his medication. A short time later he attacked his father and had to be readmitted to hospital. This second admission followed a course similar to the first with the patient ultimately returning home and assaulting his grandmother. In this case there is a clear connection between psychotic decompensation and violent behaviour. The clinician assessing this young man might hypothesize that his violent behaviour was in large part attributable to the disorganizing effects of a psychotic episode possibly influenced by family stress. The repetitive nature of violent behaviour directed at family members and associated with paranoid delusions suggests a well defined pattern. Investigations to confirm the clinical hypothesis might include psychometric testing to establish evidence of psychotic process, a psychiatric consultation for diagnostic clarification, and a social work assessment to evaluate family dynamics. If the hypothesis was confirmed, the clinician in this situation could state with considerable confidence that, should a psychotic episode recur while the patient was still living with his family, the risk of violence would be high. The history of poor medication compliance and the patient’s continued dependence on his family would further increase the probability of recurring psychotic episodes and future assaults.
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This example is particularly instructive because it illustrates the shortcomings of an atheoretical, actuarial approach to prediction. In this case, the clinical conclusions, linking psychosis with violence, are only defensible from a theoretical standpoint. A purely statistical approach might have neglected the influence of this young man’s psychiatric disturbance on his behaviour because, in general, mental illness has not been found to be predictive of dangerous behaviour (Monahan, 1981; Mulvey & Lidz, 1984; Rabkin, 1979). A theoretically based decision-making strategy can often help clinicians choose between clinical and actuarial approaches. Simply put, actuarial methods are likely to prove superior whenever predictive clinical hypotheses cannot be readily formulated or tested. This is usually so when dangerous behaviour does not show a clear pattern of association with situational or disinhibitory factors. Under these circumstances, when violence seems primarily attributable to personality features, cause and effect relationships between precipitating factors and violent actions are difficult to establish. Although personality traits such as impulsivity, hostility, aggressiveness, and antisocial orientation may have explanatory relevance (Pollock et al., 1989), there is little empirical support for their utility in predicting actual occurrences of aggressive behaviour. We simply do not yet have the necessary theoretical and technological sophistication to make reliable clinical predictions based on personality assessment alone (Goldstein & Keller, 1987; Meehl, 1986). As Kozol (1982) has remarked, “dangerous potential is not detectable through routine psychiatric examination. Nor is it detectable by any single test or combination of stereotyped tests” (p. 254). Clinical methods are most often appropriate when disinhibitory or situational factors are clearly implicated. This is largely because disinhibited behaviour and situational influences are easier to observe than personality traits and can often be evaluated and monitored with some precision. Whereas the clinician can never be certain of t,he individual’s psychological state at the time of a violent act, information about alcohol intoxication, psychotic decompensation, provocation, financial pressures, etc., is frequently available through family members, eye witness accounts, institutional records, and police reports. In conclusion, clinicians confronted with the responsibility of predicting dangerous behaviour but equipped with an imperfect technology, face a difficult challenge. Because of the longstanding emphasis on technical advancement and predictive accuracy, the scientific literature has made little progress toward the development of defensible clinical approaches to prediction. There is a need for theoretically based decision-making strategies to help clinicians judge when predictions of dangerousness are warranted, when they are possible, which methods to employ, which data to collect and how the data can be synthesized to arrive at defensible statements about dangerousness. By relying on scientifically sound, decision-making models clinicians can ensure accountability while maintaining a balance between scientific integrity and social responsibility.
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