Tabloid newspapers are fond of headlines like Maniac Kills Mum^[1,2], occasionally replacing maniac by psycho or fiend for variety. Such stories play on people's fear of mental disorder and the common perception of a high risk of violence at the hands of the mentally ill. Today being World Mental Health Day^[3] seems a good opportunity to look at the risk perception issues surrounding mental illness.

Statistics for England and Wales^[4,5] show that about 55 people (1 in a million) per year are killed by somebody with mental illness. The figure stayed much the same over a 40-year period while the general rate of homicide increased by a factor of 5. So the proportion of homicides committed by the mentally ill actually fell substantially. During the same period, large numbers of mentally-ill persons were released from institutions under the new policy of Care in the Community.

The 1 in a million risk of being killed by someone with a mental illness can be compared with the 125 in a million killed by road traffic. It's a very low risk. It's about the same as the risk of being struck by lightning in the UK. And, moreover, the stereotypical maniac risk perception involves a stranger. The truth about all homicide is that the victim is usually known to the perpetrator, often a family member. The same is true for homicides by people with mental problems. If we count only homicides committed by strangers, then about 5 per year are carried out by people with mental illness. That's a risk of about 1 in 10 million. You're as likely to be killed by lightning!

The Real Risks

The real risks are faced by those with mental illness themselves. People suffering from mental illness are more likely to be the victims of violent crime and not the perpetrators. The shift to care in the community, often without adequate service provision, has left people vulnerable to being the victims of crime. This applies to many countries, not just the UK. A study in the US^[6] found that the rate of violent crime victimization among people with serious mental illness was 11 times as much as for the general population. A study of statistics from Denmark^[7] showed that the risk of being a victim of homicide was 6 times greater for people with mental illness than for those without.

Perhaps it comes as no surprise to learn that the suicide rate among people with mental illness is 12 times higher than the rate in the general population. But it's a bit more surprising to find that the mentally ill have such an increased risk of being killed by other people. Part of the explanation is that people with mental disorders have difficulties living in the community, especially as there is often indaquate provision for them. They experience a high level of social exclusion and often find themselves having to cope with poverty and homelessness as well as their mental disorder. And it is just such groups that have a high risk of becoming victims of crime.

1. The Sun (2 December 2006) Maniac kills mum at home
2. New York Post (10 February 2007) Maniac Kills Ma
3. World Mental Health Day is a project of the World Federation for Mental Health
4. The Parliamentary Office of Science & Technology (2003) Reform of Mental Health Legislation
5. Hill , O.(2003) How much is violence associated with mental illness? (Part of the Changing Minds campaign by The Royal College of Psychiatrists)
6. Teplin, L.A. et al (2005) Crime victimization in adults with severe mental illness
7. Hiroeh, U. et al (2001) Death by homicide, suicide and other unnatural causes in people with mental illness: a population-based study