Comment apprécier la valeur probante d'une expertise en psychiatrie

R. v. Neve, 1999 ABCA 206

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[189]      What considerations potentially impact on a court’s weighing of psychiatric evidence? These include:

 

1. the qualifications and practice of the psychiatrist;

 

2. the opportunity the psychiatrist had to assess the person, including: length of personal contact, place of contact, role with ongoing treatment, and involvement with the institution in which the person is a patient or prisoner;

 

3. the unique features of the doctor-patient relationship, such as hostility or fear by the patient (or the psychiatrist) arising from the personalities, the circumstances of the contact, and the role of the psychiatrist;

 

4. specifically and precisely what documents the psychiatrist had available and reviewed, for example, from earlier court proceedings, institutional records, other medical consultations, or treatment;

5. the nature and scope of consultations (this could include: personal contact with third parties, information from other health care professionals, prison authorities, police, lawyers, family);

 

6. specifically and precisely what the psychiatrist relies on in coming to an opinion; and

 

7. the strengths and weaknesses of the information and material that is relied on.

 

[190]      There is one dimension to this evaluative task which merits comment and that is the nature and extent of the relationship between the doctor and the offender. It is important to recognize that psychiatrists, like any other doctors called as experts, can be expected to come to their opinions about a person after personal contact, performing some tests, reviewing documents and consulting with others. The psychiatrists and the offender have a type of doctor-patient relationship. The psychiatrist is, after all, a physician and the offender is, in many cases, suffering from a mental illness or behavioural disorder and is being assessed, as a result, as a possible danger to society. Indeed, the psychiatrist may actually be a doctor who is treating the offender as a patient. The court must be interested primarily in each psychiatrist’s assessment of the person under scrutiny. That is not to say that secondary sources, documents, discussions with third parties are not valid and important for the psychiatrist to review. However, taking the offender out of the psychiatrist-patient relationship may leave the psychiatrist in the role of interpreter only.

 

[191]      With respect to an expert’s reliance on secondary sources of information, whether documents or consultation with third parties, this has always been the subject of critical scrutiny by courts. Given the uniqueness of the dangerous offender proceedings and the special and mandated role of expert psychiatric evidence, such scrutiny is very important. Because weaknesses can result in an opinion which should be given little or no weight, the sentencing judge must be alive to the areas of possible weakness. Such weaknesses may include: incomplete records; lack of reliability such as might occur where a document is created for one purpose but used for another (e.g., a prison incident report being used to predict future behaviour); lack of trustworthiness such as where the subject of an interview is lying or describing fantasies as if they were realities (including in diaries); and lack of objectivity or first-hand knowledge by the author of a report. For the court to accept an expert opinion without scrutinizing and assessing its foundation is, effectively, to put that expert in the role of judge.

 

[192]      Another area of potential weakness arises from the information provided by the offender. The psychiatrists must, when coming to an opinion, deal with the possibility that the patient may be lying or fantasizing. Where the sentencing judge has heard the testimony of the offender, he or she must make a finding of credibility. Thus, in effect, both psychiatrist and judge have the responsibility of determining whether the offender is talking about what actually happened, or only what might have happened, or indeed, what never happened. The judge has the further responsibility of weighing the opinion evidence in light of such a determination.

 

[193]      Another reality which should be recognized is that psychiatrists spend far more time dealing with patients in treatment than in dangerous offender proceedings. And usually, the psychiatrists are not lawyers. Hence their “diagnosis” for treatment purposes may have different parameters and meaning to them than an assessment for the purposes of a dangerous offender hearing. Given the critical function assigned to psychiatrists by the Code, it is necessary therefore that the court be satisfied that a psychiatrist testifying in a dangerous offender hearing understand the significance of the expert opinion and the determinations to which it is directed.

 

[196]      In summary, there was a wide range and pattern of contact time between Neve and the various experts. Dr. Brooks had by far the greatest contact time, having been in touch with Neve from the time she was 15 years of age until the hearing – a period of six years. It was he whom Neve phoned when she needed help. He was the psychiatrist who treated her and he was her choice as designated psychiatrist for the dangerous offender hearing. Dr. Singh’s contact was also significant. By contrast, the contact between Neve and all of the other experts was not of long duration and seemed to be primarily of a consultative and forensic nature. The majority of the contacts with, for example, Drs. Flor-Henry and Cadsky, would seem to have been in preparation for the dangerous offender hearing.

 

[197]      We are not saying that the evidence of those experts who see an offender the longest, whether in terms of hours or over time, should be accepted or given more weight than the evidence of other experts. We mention this to flag the fact that it is a consideration which goes onto the scale in evaluating conflicting psychiatric evidence. That said, an offender cannot tip the scale in favour of his or her psychiatrist by refusing to cooperate with the Crown expert’s assessment. This too would be a factor for the sentencing judge to take into account. [We recognize that to some extent this concern has been obviated by the new dangerous offender legislation which contemplates a court-ordered assessment: s.752.1. However, since this does not preclude the calling of expert evidence by either side, the central point remains.]