Experts say most violent individuals do not have a clear mental illness, despite what gun lobbies claim.

Psychiatrists say efforts to reduce gun crime that focus on the mentally ill will miss many potential mass murderers.

Twenty years after the Port Arthur massacre, it is timely to examine how the shift in national firearms regulation has prevented injury.

The stats show that people with mental illness are actually more likely to be victims of violent crime than perpetrators - almost half of those who die at the hands of US police have some kind of disability.

But gun massacres in the US often lead to calls for better screening of mentally ill populations for violence risk, which Australian experts say could be very misguided.

Dr Michael Dudley and colleagues from the University of New South Wales, the University of Wollongong and the University of Sydney, have written a “For debate” article in the Medical Journal of Australia.

They argue that most mass murderers do not have an identifiable, severe mental illness and instead often have maladaptive personality configurations.

“Although mass murderers who seize media attention often seem to suffer from psychosis, no research clearly verifies that most are psychotic or even suffering from severe mental illness,” the authors wrote.

In the case of Martin Bryant, the lone gunman who used semi-automatic weapons to kill 35 people at Port Arthur, four forensic psychiatric reports found he was suffering from a “personality disorder with limited intellectual and empathic capacities”.

The sentencing judge concluded that he was “not suffering from a mental illness.”

Because people with mental illness are not categorically dangerous, and because of sensitivity and specificity problems with screening for violence, “psychiatrists are no better than laypeople or chance at prediction”, the experts say.

They write that clinicians have a role in monitoring and assisting regulation of firearm access, particularly in high-risk populations such as children, adolescents, suicidal people, domestic violence victims and perpetrators, farmers and rural residents, and police and security employees.

But the authors argue that wider gun control measures should be the more pressing debate.

“The campaign to deflect social concern over firearms availability into a debate about whether people with mental illness histories should access such weapons should be exposed as a calculated appeal to prejudice,” they conclude.

The full article is accessible here.