Bias as a two-edged sword

Bias, or an inability to be thoroughly impartial (Niveau Reference Niveau, Godet and Vollm2019), in this debate has been uniquely attributed the treating psychiatrist, with independence seen as conferring a degree of immunity. Regulatory bodies cited above similarly give more weight to the potential for bias within the treating clinician.

The overriding reason why courts seek expert evidence is an acknowledgement that they require assistance in the interpretation of evidence from highly complex specialised disciplines such as medicine (R v Turner [1975]). In that respect the role of the expert is more that of an educator or adviser.

In Canada, this issue was addressed in a judicial review of expert witnesses, as part of the Civil Justice Reform Project: ‘too many experts are no more than hired guns who tailor their reports and evidence to suit the client's needs’ (Osborne Reference Osborne2007: recommendation 9).

Relative bias between treating physicians and independent experts was later argued in the Ontario Court of Appeal in the matter of Westerhof v Gee Estate [2015]. In brief, this was a civil case in which the plaintiff relied on evidence from their treating physician, which had been ruled inadmissible by a lower court. This in effect meant that a plaintiff needed to acquire ‘hired gun’ expert testimony instead of a family doctor, which, as a barrier to effective justice, prompted the appeal. This decision was critiqued as follows:

This ruling expressed a view that the opinions of treating physicians may be less biased than those of the experts retained for litigation. This is because treating physicians had likely formed a clinical opinion about questions relevant to the court before litigation was the goal.

Closer to home, the findings by the Rt Hon Lord Woolf leading up to the Access to Justice Act 1999 reflected a crisis in civil litigation, where expert evidence was such an unnecessary generator of cost (owing to a large expensive parallel support industry) that it fundamentally undermined access to justice (Woolf Reference Woolf1996: ch. 13). The recommendations were an attempt to correct what had become the conduct of partisan experts within an adversarial system under the sway of market forces.

Many of our psychiatric colleagues have seen independent experts making significant recommendations on patients under their care based solely on a single brief assessment without full knowledge of the history. Increasingly such assessments are being formally sanctioned owing to poor practice (Rix Reference Rix, Eastman and Haycroft2017) or criticised from the bench (R v Choudhuri [2019]: paras 81–94) – involving the court directly criticising an expert as having failed to ‘grapple with the obvious alternative explanation’ in the proceedings, based on a single brief interview.

The consequences not only reflect negatively on the credibility of psychiatrists (Daggitt v Campbell [2016]), but may lead to unworkable recommendations owing to a lack of understanding of local service structures or processes.

On the question of reliability, Large et al (Reference Large, Nielssen and Elliott2010) in comparing the agreement between treating clinicians and independent experts concluded that ‘concerns about bias arising from the nature of a treating practitioner's relationship with a patient may be overstated’. Given that two psychiatrists are often necessary for crucial issues such as hospital disposal, fitness to plead or diminished responsibility, having one independent psychiatrist should balance any perceived bias from the treating psychiatrist.

Ethical dilemmas

The GMC's guidance on good medical practice places the welfare of the patient at the heart of any clinician's concern. With the expert witness's overriding duty being to the court, it would seem impossible to serve two masters – but only if we take the narrow view that assisting a patient by providing unbiased evidence to the court is inevitably harmful. We argue this is not a given. This is because any independent expert must also adhere to good medical practice.

A case could be argued that a sensitive disclosure made prior to litigation was done with an expectation of confidentiality. This is mitigated by the fact that the treating physician cannot undertake expert witness instruction without the patient's consent except under specifically defined exceptional circumstances. We argue that the relative independence of the expert does not resolve the matter either way.

Furthermore, the assumption that there will be a conflict between the interests of the patient, the court and the expert is not inevitable. Objectives often align. When they do, there is clear merit in the court being aware of the specific treatment plan and local resources. Here the treating clinician could have a distinct advantage.

Rupture of the therapeutic relationship

The effectiveness of psychotherapy understandably relies on the relationship with the therapist. Much has been debated over the strain acting as an expert witness may place on the therapeutic alliance. However, in our view this may be overstated.

In England and Wales, the Tier 1 Mental Health Tribunal (MHT) system mandates evidence from the treating clinician. This evidence regularly conflicts with the expectations of the patient, given that they are appealing in pursuit of discharge. The low success rates of appeals to the MHT speaks to this inherent friction (Gosney Reference Gosney, Lomax and Hooper2019).

Whenever the distinction between the MHT and other courts is raised, it is often reframed within their different roles, their adversarial versus inquisitorial nature, or the technical role of the responsible clinician. However, in both processes there are conflicting views, a perceived power imbalance, the liberty of the patient at stake and the testimony of the treating psychiatrist likely going against the patient's preferences. Therefore, such differences are largely semantic. Treating clinicians have had to make do with this situation and devise strategies to heal such ruptures when they arise, and have done so successfully.