Abstract
The rules of admissibility of expert evidence from mental health professionals are not clear. The task of a psychiatrist providing expert opinion to criminal courts is far from clear. Psychiatric experts are trained in a particular set of ethical and philosophical frameworks. They have expertise in the diagnosis and management of behaviours arising from mental disorders. The concept of mental disorder itself is a dimensional one. Such a dimensional view of human behaviour and mental disorders is hard to fit into the categorical view of human behaviour that the law follows. The task of the psychiatric expert is to marry these two philosophically different branches. Such a task would be facilitated by clear rules of admissibility of expert psychiatric evidence, clear definition of the roles and limitations of psychiatric evidence in criminal cases, a better understanding and training of mental health professionals in legal principles and a better understanding by the legal professionals of the mental health concepts. This article aims to analyse the legal basis of the admissibility of expert mental health evidence, the differences in the philosophies of the two disciplines and the challenges in addressing legal criteria while staying faithful to the ethos of psychiatry and psychology.
Introduction
There is a long tradition of incorporating expert evidence in criminal proceedings with an aim to improve the quality of decision-making and assist the courts in matters outside the experience of legal professionals and jurors. This principle was expounded by Saunders, J. in Buckley v. Rice Thomas as early as 1554. 1
Mental health professionals have long been assisting the courts in their capacity as expert witnesses. The main issues where the criminal courts seek the assistance of mental health professionals include: fitness to plead, insanity, diminished responsibility, automatism, formation of intent, intoxication, provocation, duress, admissibility of confessions and psychiatric disposals. 2
The rules on admissibility of expert evidence from mental health professionals are not clear. The marriage of philosophically different worlds of mental health and law comes with a unique set of challenges. This article aims to analyse the legal basis of the admissibility of expert mental health evidence, the differences in the philosophies of the two disciplines and the challenges in addressing legal criteria while staying faithful to the ethos of psychiatry and psychology.
Legal basis of admissibility – case law
The classic case of Turner 3 established initial guidelines on the admissibility of psychiatric opinion in criminal courts. Lawton J in the Court of Appeal ruled that the first question in deciding the admissibility of psychiatric opinion is the relevance of such an opinion. However, the expert opinion has to go beyond relevance and furnish the court with scientific information outside the experience and knowledge of the judge and the jury. If on the proven facts the judge and the jury can form their own conclusions without help, then the opinion of an expert is unnecessary.
Turner was applied in Weightman, 4 where the Court of Appeal ruled that ‘the psychiatrist's opinion is inadmissible where its purpose is in effect to tell a jury how a person who is not suffering from mental illness is likely to react to stresses and strains of life’ (McCowan LJ at p. 297).
A similar view was expressed in Chard, 5 a case decided before Turner, where the Court of Appeal held that in absence of insanity, diminished responsibility or mental illness, evidence from a medical expert on the defendant's state of mind at the time of the offence was inadmissible.
In Toohey, 6 the court ruled that the defence may call medical evidence to challenge the credibility of a prosecution evidence if the evidence shows that the witness suffers from ‘some disease or defect or abnormality of mind that affects the reliability of his evidence’.
Rules derived from Turner
The rules that can be derived from Turner are: that mental health experts may testify on matters that fall outside the knowledge of the judge and the jury, and that such matters should concern mental abnormality, and that expert evidence relating to personality traits is inadmissible. 7
Such a reading of Turner is very restrictive for several reasons. To begin with, it assumes that there is a clear-cut distinction between mental illness and normality, a view does not fit comfortably with the modern dimensional view of mental illness.
As per Turner, the expert evidence is admissible if it falls outside the experience and knowledge of the judge and the jury. The imprecision of this rule reduces its practical value as a guide to expert witnesses 8 and the judges, who have to decide whether the expert opinion deals with normality or abnormality.
Assuming that the judge and the jury can form valid opinions on the mental state of those not deemed to suffer from a recognizable mental illness, such opinions would be based on the limited knowledge of the person that the judge and the jury get in the course of the adversarial proceedings. In contrast, the expert opinion would be based on a structured interview, conducted in an inquisitional manner and supported by the person's previous psychiatric notes and sometimes by scientifically validated rating scales. In certain cases such an assessment would carry on for several days, e.g. as an inpatient under Section 35 of the Mental Health Act. An expert who concludes, at the end of such investigations, that a person does not suffer from a recognized mental disorder may still have useful contributions to make.
Roberts 9 suggests a much broader reading of Turner. He asserts that the test is whether the expert evidence will be sufficiently helpful to the jury to offset any disadvantage that its admission is likely to entail in terms of lengthening the proceedings, increasing their complexity or diverting the jury's attention.
Beyond Turner
In many cases, courts have gone beyond Turner and shown a greater willingness to accept psychiatric evidence in a wider range of scenarios. In Raghip, 10 on the question of admissibility of confessions under section 76 of the Police and Criminal Evidence Act 1984, the Court of Appeal allowed psychological evidence even though the defendant did not meet the criteria for diagnosis of a mental disorder (his intelligence quotient [IQ] score being 74). The court pointed out the artificiality of a strict cut-off point for IQ tests. A distinction was, however, drawn on the admissibility of expert opinion on the mental state at the time of offence and admissibility of such an opinion at the time of confession. In the absence of a mental illness, the former was deemed not admissible but the latter was admitted. There is no logical basis for such a distinction for if expert help is needed to understand the mental state at the time of police interview, it surely must be needed to understand the mental processes at the time of offence.
In Miller, 11 a case where the defence asserted that the confession was obtained under oppression, the psychological evidence was admitted despite the defendant with an IQ of 75 not fulfilling the requirements for diagnosis of a mental disorder. This is in contrast with Masih, 12 where the expert evidence was excluded on the basis that the defendant's IQ score was above 70 and therefore he did not fulfill the criteria for diagnosis of a mental disorder.
Psychiatric evidence is now commonly admitted to explain ‘battered woman syndrome’ 13 and it was deemed admissible for childhood amnesia (R v. H). 14 Neither of these is recognized as a mental illness.
As per Hurst 15 the essential qualities of admissible psychiatric evidence are: the evidence must fall squarely within the boundaries of the witnesses’ expertise; the evidence must, on balance, offer assistance to the court; and the evidence must defer to the values, objectives and priorities of criminal proceedings.
These cases demonstrate the inconsistency in the courts’ approach to admissibility of expert psychiatric evidence. The courts are engaged in a more expansive and difficult task than to merely apply some ‘abnormality’ or ‘common knowledge’ rule. Seen in this context the perceived inconsistency to admissibility of psychiatric evidence is more intelligible but this does not make it any easier for the expert witnesses. There are general principles but no clear-cut rules. Even where the experts are clear about the rules of admissibility there are other issues that need to be overcome as the expert is involved in the precarious task of marrying two disciplines with their distinct ethos and principles.
Psychiatry and law have their origins in different philosophical contexts. While the role of medicine (and psychiatry) is to understand human illness and health and find ways of helping people maintain an optimum degree of health, the role of law is to lay down the basic rules of behaviour in human society and implementation of such rules.
Courts have been assisted by medical experts for several centuries but a number of difficulties can be identified in this relationship: 16 communication, different models, ethical dilemmas, changing concepts of mental illness, teleology (cherry picking of the evidence), pretextuality (expert evidence used to achieve socially desirable aims) and sanism (allowing prejudicial and stereotyped evidence).
Communication
The role of an expert is to furnish the court with opinions that the court does not have knowledge or experience of. This requires an understanding of the legal principles and an understanding of what the court wants to know in order to reach its overriding objectives.
A psychiatric report may be filled with complicated medical terms
4
and this coupled with impressive qualifications risks lending it a false credibility. Lawton L J in Turner warns:
‘The fact that an expert witness has impressive scientific qualifications does not by that fact alone make his opinion on matters of human nature and behaviour within the limits of normality any more helpful than that of the jurors themselves; but there is a danger that they may think it does.’
This can be remedied by the expert using plain English and providing a glossary of medical terms. 17 The Criminal Procedure Rules, Part 33, requires the expert to summarize the range of opinions possible in a particular case along with the reasons for his own opinion. 18 The experts must be clear about the limitations of their knowledge and avoid being tempted to answer questions beyond their competence. 19
Research reveals that the legal knowledge of mental health professionals can be limited. Brewster et al. 20 found that only 40% of psychiatric reports in their sample applied the correct test for fitness to plead. Larkin and Collins in appraising the use of English legal test for fitness to plead found that only a third of the reports studied made a statement on fitness to plead supported by standard legal criteria. 21
Peay et al. (2001) found that the mental health law knowledge of mental health professionals was limited. This study revealed that the mean knowledge score of Section 12(2) approved doctors (doctors approved by the Secretary of State for health as having special experience in the diagnosis and treatment of mental disorders) was 76.4 out of possible 100. 22 Given that the mental health law determines the day-to-day practice of mental health professionals, the knowledge of the criminal law can only be assumed to be poorer.
One of the ways to remedy this is for the expert to have a detailed discussion with the instructing solicitor to clarify the questions being asked of the report. 23 As Jacob J stated in Routestone 24 ‘it is a good thing for the expert to have given to him the legal test … ’ In view of the evidence of limited legal knowledge of psychiatrists one could argue that is more than a good thing, that it is essential.
It has been debated whether the expert involved in the field of legal psychology and psychiatry needs to be formally trained in law. 25 The benefits are obvious, but it is an expensive and time-consuming exercise and most of the expert witnesses deal with limited aspects of the law. 26 In the UK, the Royal College of Psychiatrists expects an understanding of criminal, civil and case law relating to patient care in forensic settings, as a required competency of a forensic psychiatric trainee. 27
Different models
Doctors and lawyers come from different backgrounds. Doctors have their medical model and lawyers their legal model. The medical model is holistic, deterministic, biographic 28 and dimensional. The medical model views health as a combination of physical, social and mental well-being and not merely the absence of disease or infirmity. 29 In contrast the legal model tends to be rational, de-contextualized 30 and dichotomous and believes in free will.
Medical determinism
There is a fundamental philosophical difference in how law and medicine view the issue of criminal responsibility along the continuum from free will to determinism. The law has long assumed that human behaviour is the product of free will or at minimum a rational choice, while neurosciences (which include psychiatry, psychology and neurology), focusing on biopsychosocial models of mental illness and health, tend to favour determinism. 31
A deterministic model would assume that there is no free will and every action is determined by a combination of a person's genes, environment and early experiences. The position on free will is that we are fully responsible, capable of controlling our behaviour, able to distinguish right from wrong and to act reasonably and in accordance with laws and social conventions.
Not many psychiatrists would take the extreme deterministic view and not many courts would totally reject the deterministic model when psychiatric evidence explains a behaviour that stems from mental illness. However, there is a reluctance to accept elements of determinism if there is no recognized mental illness. 32
Dichotomy versus dimensionality
The legal model tends to favour dichotomy. So if the defendant suffers from a diagnosable mental disorder the psychiatric report is relevant and various defences can be accessed. On the other hand if there is no diagnosable mental disorder it gets harder to admit psychiatric or psychological evidence.
This was the problem in Masih 33 where an IQ score of 72 meant that the psychiatric evidence was inadmissible. This is in stark contrast to the dimensional view of illness and health followed in psychiatry. Such a black and white distinction between normality and abnormality may help to have a clear cut-off for the courts and statisticians but it does not reflect the modern dimensional view of the working of the mind (or brain).
The IQ of a population falls on a continuum with the majority of the population falling within one standard deviation of the mean. Under the dimensional model the behaviour and vulnerability would be explained on this continuum. An arbitrary cut-off, two standard deviations from the mean IQ, is selected based on a statistical convention. An IQ of 72 would still place the person near the bottom 2% of the population. Even if one were to accept this statistical cut-off, the IQ test itself has a margin of error. This demonstrates the disadvantages of a dichotomous view of mental abnormality and how the meaning of an expert's psychiatric knowledge can get lost in the translation.
Decontextualization
Hurst 15 demonstrates the decontextualizing model of the law and its ill fit with the biographic model of medicine. The defendant was a woman with a history of physical and sexual abuse from various men throughout her life. Dr P Mellet, a consultant psychiatrist, prepared a report in which he expressed the opinion that in the context of the defendant's history of abuse she would have found it hard to resist the demands placed on her by another person and thereby she had acted under duress.
This evidence was deemed inadmissible, as, among other things, the hypothetical person with a reasonable fortitude could not be invested with the defendant's personal history and personality traits. Dr Mellet's view of the defendant and her actions sit diametrically opposite to the court's view. Looking at the decision, both were correct in their respective models. In the court of law, legal principles take precedence; the story might be different in a mental health setting.
Reasonability
The law assumes that ideally human behaviour is to be guided by reason, hence the normal person test in defence of loss of control (this replaces the reasonable man test in defence of provocation) or the reasonable firmness test in the defence of duress. The jury is left with the hard task of investing the reasonable man with the characters of the defendant except for the ones whose only relevance is to impact the person's firmness 34 (in duress) or the persons self-restraint 35 (in loss of self-control).
Sections 54–56 of the Coroners and Justice Act 2009, replaces the reasonable man test in the defence of provocation with a ‘normal person’ test. In this test, the mental state of the defendant can be taken into account unless its only relevance is to make the defendant less tolerant and less able to exercise self-restraint. It is hard to see how the ‘normal person’ is any easier to define than the ‘reasonable man’.
Such a view of human behaviour assumes that there is a hypothetical ‘normal person’ or ‘reasonable man’ and that various aspects of mental health and personality can be dissected from each other. This view of human behaviour is out of sync with the holistic behavioural model of medicine, psychiatry and psychology.
Ethical dilemmas
The principles of an ethically sound psychiatric practice are beneficence (acceptability of responsibility to do good), non-malfeasance (do no harm), autonomy (respect for freedom of thought or action), fidelity (trustworthiness to commitments) and a general respect for person's rights. 36 The medical profession promises respect, choice and confidentiality for users. 37 Such principles are not easily applicable to legal systems. 38 Psychiatric expert testimony may lead to undesirable outcomes for the subject of the opinion, such as a longer than usual sentence. It may adversely impact the therapeutic relationship between a patient and the clinician.
American and Australian psychiatric codes of ethics take the view that the expert relationship is not a therapeutic one and therefore the subject is not a patient, and the welfare of the subject is not the expert's main ethical concern. As per the Royal College of Psychiatrists, the fact that the expert did not know the subject before the court proceedings does not absolve the expert of responsibilities to the patient, for, once the subject has consented to become involved with the expert, a doctor–patient relationship is established. 39 At the same time, the expert's duty to help the court to achieve its overriding objective trumps any other obligation that the expert might have. 40
This does not mean that some of the traditional medical ethical duties like respect for autonomy cannot be fulfilled e.g. by explaining the limits of confidentiality and seeking the patients’ permission prior to disclosure. Where the report risks damaging the therapeutic relationship, it may be advisable to ask for an independent professional to prepare the report, someone who is not involved in the day-to-day care of the patient.
Rise of neuropsychiatry
Many of the legal tests that deal with mental illness were developed in the nineteenth century and have been a part of the common law for a long time. They do not always reflect the developments that have taken place in psychiatry and its understanding of mental disorder. We continue to use the derivatives of the Pritchard criteria (1836) and M'Naghten rules (1843). The law commission recommendations on modernizing the Pritchard criteria are welcome but the fact that the test survived nearly two centuries (assuming the recommendations are accepted) goes to demonstrate the emphasis that law places on the principle of stare decisis (the principal that the precedent decisions are to be followed by the courts unless replaced by a new decision by an equivalent or a higher-ranking court). This is in stark contrast with scientific fields where, what is past is largely a prologue. The law continues places significant stress on the mind, while in modern neuroscience the mind has largely been incorporated as a function of the brain. The future developments in understanding human behaviour are expected to come increasingly from neurological research into brain function. 41 The expert witness is expected to translate this rapidly evolving medical currency of brain functions into the legal currency of mind and these two currencies are not always interchangeable.
Teleology, pretextuality and sanism
Assuming that the rules of admissibility are clear and the medical principles are translated into legal tests, how do the courts evaluate expert evidence? Perlin et al. argue that judicial decision-making, and, in fact, the expert reports, are influenced by teleology (cherry picking of the evidence), pretextuality (expert evidence used to achieve socially desirable aims) and sanism (allowing prejudicial and stereotyped evidence). They assert that in considering expert evidence the courts ‘cherry pick’ evidence to justify judicial decisions. The evidence that allows the judges to satisfy predetermined positions is preferred over the evidence that questions such positions. They further argue that expert witnesses and judges are guilty of distorting testimony in order to achieve socially desirable goals. They conclude that:
‘Much of the judicial decision-making in the area of mental disability is pretextual and this pretextuality flows from sanist roots.’
42
Champine (2006) found inaccuracies in decision-making by mental health professionals in forensic contexts and explained the difficulties that the clinicians had in applying legal standards. 43 Studies have concluded that risk assessments are routinely clouded by bias, 44 an expert testimony by psychologists is affected by hindsight bias 45 and expert testimony is often a result of cognitive errors and erroneous beliefs. 46
It appears that even where the rules are clear, the expert evidence may not always lead to courts achieving the overriding objectives of justice and fairness. These biases are more likely to flourish in a system where the legal tests are unclear and can be reduced by more legal training of experts and possibly a better mental health awareness of the legal professionals.
Conclusion
The courts are receiving an increasing range and depth of psychiatric evidence but the rules of the admissibility are uncertain and inconsistent. The psychiatrists’ understanding of the legal principles leaves much room for improvement. There is an added problem of bringing together the philosophically different worlds of mental health and law. These two disciplines have different purposes, ethical frameworks and models. The expert has to deal with the difficult task of fitting the medical principles into legal frameworks. The courts are expected to keep pace with the rapidly changing field of medical sciences while maintaining the principles of continuity and stare decisis. All these factors contribute to the difficulties in addressing the relevant legal tests in expert psychiatric evidence.
There is a need for increased understanding on both sides. The legal professionals need to have more up-to-date understanding of the basic principles of psychiatric practice and human behaviour while the psychiatric experts need to familiarize themselves with the legal principles and court procedures on the issues that they give evidence on. There is a need for regular review of the law and a necessity to keep pace with rapidly changing medical knowledge, and there is a need for clearer rules on the admissibility of psychiatric evidence.