Report says 44 out of 105 fatal shootings in the past 22 years were of people with mental illness

Close to half the people shot dead by police over the past 22 years had some form of mental illness, latest figures show.

According to a new report from the Australian Institute of Criminology, there were 105 fatal police shootings between 1989-90 and 2010-11 and 44 of those people had a mental illness, with psychotic disorders such as schizophrenia being the most common.

Drugs and alcohol are also overrepresented, with postmortem toxicology results showing in 51% of fatal shootings the victim was intoxicated.

The report comes as the mother of a boy shot by police in 2008 filed a landmark action with the United Nations designed to overhaul Australia's procedure of investigating the police.

A separate study in 2010 by researchers at Monash University looked at fatal shootings by Victorian police between 1982 and 2007, and concluded mentally ill people were "significantly overrepresented" in fatal shootings with psychosis and schizophrenia in particular 11.3- and 17.3-fold higher than estimated rates in the general population.

Professor James Ogloff, one of the authors of the Monash study said that following their research findings the Victorian police instituted new training to help officers deal with irrational people.

"They now have action-based training scenarios that involve interacting with people with mental illness," he said.

"When people are typically in a crisis what happens is they're not terribly rational and the normal way police deal with people may not be effective."

NSW has had the most recent police shootings out of all states, with a total of seven deaths between 2008 and 2011 according to Australian Institute of Criminology figures.

Frank Quinlan, chief executive of the Mental Health Council of Australia told Guardian Australia that the statistics represented broader flaws in the provision of mental health services throughout Australia.

"I don't believe the messages of these events are straightforward or simple, because while they involve police officers and a distressed individual, they're just the pointy end of a whole system of attitudes, services and processes that has failed," he said.

"Understanding and appropriate training for police officers who are the first responders in many of these instances is clearly an important part of the picture, and if people are receiving inadequate training or if they're not receiving training often enough, then I think that is an important issue for us to look at. But we also need to ask in that context why is it that for this disease, mental illness, we are asking police to be the first responders so often.

"International evidence is starting to suggest that the involvement of accredited peer workers with first responders, people who have experienced mental illness themselves, can also be an effective way of de escalating and avoiding the ultimate use of lethal force."

There have been a number of high-profile police shootings of people with mental illness in recent years. In November 2009 Adam Salter was shot at his home in Lakemba, Sydney after police had responded to a call saying Salter was trying to stab himself. Salter had a history of mental health illnesses and had recently been held as an involuntary patient at the Concord Centre for Mental Health, before being discharged back into the community.