The RCPsych Article of the Month for November is ‘Expert evidence: dangers and the enhancement of reasoning‘ written by authors Mr Justice Peter Charleton and Mr Ivan Rakhmanin. The article is published in BJPsych Advances and is free to access for one month.

I’ve heard many psychiatrists giving evidence. And, maybe hundreds of experts in multiple cases over a 45 year career as barrister and judge.

Some experts are routine – the treating doctor in a road accident claim – while others are indispensable – the psychiatrist testifying that the murder accused did not know the nature and quality of their action.

Courts cannot function without experts. Why? Because judges and jurors have not studied psychiatry, medicine, chemistry, in fact any discipline that needs specialist education; the test for admitting expert evidence. We depend on experts not to guide us, but to expand our capacity to matters outside our competence.

Often lawyers complain: ‘why can two experts never agree?’ Ignoring, the uncertainty of the law, despite our best efforts, and that even in the highest courts judges dissent. How is it, some say, if an expert says ‘My duty is to the court and not to the party who retains me’, courts may dismiss their testimony?

Well, of course, experts are as human as any witness and, remember, it is only experts who are paid to testify.

Apart from that, experience teaches us that it is only natural for experts, immersively consulting with the side that needs their evidence, to feel themselves part of a team: hence, hostile to any opposing viewpoint. So, judges are repelled by any sectional presentation.

But, what else are we thinking?

Well, unless a judge sits doing psychiatric-type cases daily, unlikely because that’s only a few homicide cases and equally few injury assessments where mental damage is claimed, we first embark on a swift catch-up. Can I grasp the science here? That’s our primary consideration. We are most helped by what is clear, principled and objective. The fundamentals explained first: because from basics we can go on to the nuances of why the accepted science is claimed to apply. What we understand is next applied to the facts we regard as key to the case. We do that best where an expert engages with debate: less, where there is a retreat into obscurity, jargon and, worst, an air of ‘I am a professor and I know best, so why question my viewpoint?’

Clinical practice differs from legal work. Clinicians are geared to treat; scientists to revise and postulate only what is empirically proven: lawyers promote asserted facts and dispute all contradiction. But, just as experts see some things as key, a judge filters away evidence towards the fulcrum of the case. So, the more an expert can address what matters, the better.

Lastly, consider two aspects of the lawyer’s mind. First, we tend to put rules on what needs a more open-ended approach. Hence, we ask ‘is the testimony internally contradictory’, even where there is no aspect of the opposite case worth engaging with. Secondly, while not suspicious, courts need reasons to trust witnesses. It is not just qualifications that impress us but, above all, the feeling that this person is here to assist.

That’s what we value the most.

Mr Justice Peter Charleton and Mr Ivan Rakhmanin’s article titled ‘Expert evidence: dangers and the enhancement of reasoning’ is chosen as the RCPsych Article of the Month. This article provides an unique insightful window in to the minds of legal luminaries and expectations of courts, is a ‘must read’ for practicing psychiatrists and mental health professionals, for developing and preparing themselves to provide expert evidence, used to assist the court for administration of justice.

Professor Asit Biswas
Editor-in-Chief, BJPsych Advances