“Lawyers say the question of mental fitness is a legal one – whether someone had the capacity to be convicted of an offence at the time of the offence. While psychiatrists say it’s a psychiatric prognosis,” she pointed out.

“Understanding where the other set of professionals is coming from is the challenge. This requires lawyers to take into account the psychiatric perspective and, equally, for medical practitioners to acknowledge the courtroom context.”

Case in point

The decision in the Peter Sutcliffe case is an example of how these courtroom tensions can play out, said Loughnan.

In 1981, the British serial killer dubbed ‘The Yorkshire Ripper’ pleaded guilty to the manslaughter of 13 women on the grounds of diminished responsibility. The prosecution intended to accept Sutcliffe’s plea after four psychiatrists diagnosed him with paranoid schizophrenia. But the trial judge, Justice Boreham, claimed the case was of significant public interest and ordered the matter be heard by a jury. Sutcliffe was subsequently found guilty of murder on all counts and sentenced to life imprisonment.

“In this case, there are medical professionals with a set of conclusions about the person’s condition who have translated these into the language required by the law, but you still have legal questions around whether it’s appropriate to go to trial and proceed through the normal criminal process,” Loughnan said.

She added that the case raises questions around “dangerousness” and whether criminal law is appropriate for defendants with serious impairments.

“If we’re dealing with defendants who are not going to be responsible in the relevant way and appropriate subjects of punishment, we need to think about whether a different approach is needed.

“As lawyers, we need to recognise the need to protect the community, and perhaps the defendant themselves, from harmful behaviour.”

Loughnan also said there is another perspective that demands attention – the beliefs and attitudes of the lay juror.

“Lay people are bringing a more sophisticated understanding of clinical conditions and labels, as well as a reduced stigma around mental illness, to the courtroom.

“If we take this lay knowledge seriously, we would recognise that while we see a ‘turf war’ between experts of different stripes, there is actually a three-way dynamic between experts and non-experts.”