You can't just lock up psychopaths

THE HOME Secretary's outburst in the House of Commons on Monday almost certainly encapsulated public outrage and bafflement at the inability of psychiatrists to prevent the murder by Michael Stone of Mrs Russell and her daughter. Jack Straw found the statement by the local health authority that Michael Stone was not mentally ill "extraordinary", and instead suggested that 20 years ago any decent doctor would have done the right thing, and locked Stone up whether treatable or not.

All good populist stuff, but was it legal, decent or truthful? The answer is "no" on all counts. First of all, was Michael Stone mentally ill? The Health Authority, for once, came out of its corner fighting, and said he wasn't. Instead he had an antisocial personality disorder, which is doctor-speak for being a nasty piece of work. It is true that some people with mental illness are indeed violent and dangerous - but being violent or dangerous does not prove someone is mentally ill.

But let's give Mr Straw the benefit of the doubt, and assume that Stone did have a mental illness after all - would that be sufficient justification to detain him in hospital? Again the answer must be "no". With the benefit of hindsight, everyone would wish that had happened, but is that possible?

On paper it looks easy. We know a lot about the kind of things that increase the chances that someone with a mental illness will do something awful - being male, coming from a broken home, spending time in care, having previous convictions for violence, and using drugs - all of these are clearly associated with future risk of violence. When we look into the background of those with mental illness who did indeed commit a savage offence, that is what we usually observe. All of them were also present in the background of Michael Stone. Open and shut case, then.

But think for a moment just how many other people have similar backgrounds, yet do not commit hideous crimes. Sadly the answer is "lots". It is the problem of using something which is relatively common - 30 per cent of the male population, for example, have a criminal conviction by the time they reach 30 - to predict something which is thankfully very rare: murder.

Thinking only about people with a clear-cut mental illness, schizophrenia, and assuming that we know everything there is to know about the background of the people in question, then for every serious crime we would prevent by locking somebody up, we would detain about five people who would not have committed an awful offence. In the real world, where we never know everything there is to know, it would be far worse.

Michael Stone, according to the doctors, was what is often called a "psychopath". This is someone who consistently acts in a profoundly antisocial manner, and does so without any regard for the feelings of others. There is a debate among psychiatrists as to whether this is a mental illness, or a way of describing people no one likes and most are frightened of. There is less debate about whether psychiatrists can do anything about it - most psychiatrists say not.

The Mental Health Act, the law enacted by Parliament, states clearly that you cannot detain a psychopath solely to protect the public, but only if he or she is treatable, which they usually aren't. If the psychiatrists who tried to help Michael Stone had detained him against his will, they would have been breaking the law.

It is surprising that the Home Secretary seems not to know the law on this point. Instead he is suggesting something that in other contexts would be called "internment without trial" - locking people up in hospital, whether they are treatable or not, in case they might in the future do something awful.

It would not succeed. We no longer have the beds to treat those who need treatment, let alone those who can't be treated. It is also unfair. The knee-jerk assumption that Michael Stone must be mad because he did something horrible does nothing at all to ease the stigma of mental illness - universally acknowledged to be a major problem blighting the lives of those with mental disorders.

Finally, even if Jack Straw's vision came to pass, who would be around to put it into practice? Not me for sure. Psychiatrists are doctors, not gaolers. Psychiatry is part of medicine, not penal studies.

If, in the future, I am expected to train at Hendon Police College rather than medical school, count me out.

Simon Wessely is Professor of Psychiatry at King's College Hospital, London