Health

Killings by people with mental disorders in England and Wales have fallen by two-thirds in the past quarter century, and are now at historically low levels.

The finding, based on an analysis of official homicide statistics from 1946 to 2004, reveals that public concerns about increasing violence by mentally ill people are unfounded.

Matthew Large, an independent psychiatrist based in Sydney, Australia, and colleagues who performed the analysis, say their findings could reignite the controversy that surrounded the passing of the UK's 2007 Mental Health Act.

Most mental health professionals believed that rates had stayed constant for decades, and even declined as a proportion of all homicide - the conclusion of a 1999 report in The British Journal of Psychiatry analysing data from 1957 to 1995. Critics believed the act had been passed as a knee-jerk response to public fears.

Declining rates

But not only does the new analysis detect no recent increase in homicide by mentally ill people, it also contradicts the finding that rates have stayed constant.

Instead it found that homicides due to mental disorders peaked in 1973 at a rate of 0.245 per 100 000 people - equivalent to well over 100 homicides per year. The rate then declined, even though homicides that were not related to mental disorder continued to climb.

By 2000, homicides related to mental disorder had fallen by two-thirds to 0.07 per 100 000, remaining at those historically low levels until 2004, the last year for which data was analysed. Total homicides peaked at 1.5 per 100 000 in 2004.

The new findings could prove embarrassing to the British government.

Under the 2007 Mental Health Act, in November this year it becomes possible to compel a person with a mental illness living in the community in England or Wales to undergo treatment under "Supervised Community Treatment" orders.

Public misperceptions

Mental health advocates have argued that Supervised Community Treatment is overly coercive, and that it was introduced to allay public misperceptions about violence by people with mental illness.

"We have to be aware that only a tiny proportion of people with mental health problems commit homicide, and not use [these rare cases] to build our mental health policies for the thousands of people," says Andy Bell, chair of the UK's Mental Health Alliance, a group of 75 organisations, which campaigns on mental health legislation.

There is no data for long-term trends in homicide by people with mental illness in the US.

But "there is a much increased perception that people with mental illness are violent," says Ira Burnim of the Bazelon Center for Mental Health Law in Washington DC.

Cultural stereotypes

According to Burnim, that's because of portrayals of violent people with mental illness in popular culture.

The cause of the apparent fall in homicides by mentally ill people in England and Wales is uncertain. Large and his colleagues suggest that the fall is most likely due to an improvement in treatment. Antipsychotic drugs became widely available in the 1970s, the point where the rates started to fall.

"It is ironic then, that in the UK there has, since the 1990s, been a 'moral panic' about homicides by people with mental disorders," says George Szmukler, of the Institute of Psychiatry, King's College London. "It's a rather sad story of stereotyping of the mentally ill as dangerous, and how mental-health policy is so little influenced by evidence."

Journal reference: The British Journal of Psychiatry (DOI: 10.1192/bjp.bp.107.046581)

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