NO Simon Wessely, member of the Royal College of Psychiatrists



Next week the American Psychiatric Association is publishing its fifth take on the classification of psychiatric disorders, the DSM-5. Judging by the sound and fury, you might be forgiven for thinking that this is something radical – a great breakthrough in our struggle to better understand mental disorders, or alternatively a dastardly plot to extend the boundaries of psychiatry into everyday life and emotions at the behest of greedy drug companies. Or, if the position statement from the Division of Clinical Psychology (DCP) is to be believed, an attempt to emphasise the biological causes of mental disorders over the social and psychological.

In fact, it is none of the above. A classification system is like a map. And just as any map is provisional, ready to be changed as the landscape changes, so is classification. Our knowledge of the changing landscape can come from many sources. This week's Lancet, for example, highlights new research showing the genetic overlaps between several serious psychiatric disorders, which call into question the current boundaries between schizophrenia and bipolar disorders (genes matter, even if we don't yet fully understand how). I expect that the map of severe mental illness in DSM-6, when it appears, will have been redrawn and that it will be on the basis of a better biological understanding of those disorders.

But does that mean that, as the DCP is saying, psychiatry is gradually being taken over by the biologists, attempting to reduce human experience to the level of molecules and cells? The answer is an unequivocal no. Psychiatry is the study of the brain and the mind. Psychiatrists look at the whole person, and indeed beyond the person to their family, and to society. That is why even as a medical student I knew that psychiatry was for me – it was about biology, but it was also about psychology, and sociology, ethics, politics and much else. Psychiatrists react to the tired arguments about biology versus psychology in the same way as geneticists react to sterile debates about nature versus nurture – it's both. Mindless psychiatry is as unhelpful as brainless psychiatry, and the psychiatrist who ignores the social environment is, well, not a psychiatrist. Political decisions about the economy in, for example, Greece or Russia have had serious consequences on some, but not all, mental disorders.

So why the fuss about DSM-5? After all, it's hardly a good read – not the kind of book anyone will take on holiday – and it isn't the system of classification that we use over here in any case. In practice, most UK mental health professionals will barely notice much difference. Some diagnostic criteria will have improved, others less so, and no doubt there will be some "only in America" stories about the inevitable daft new category. But most of those in the business of helping those with mental disorders will be less concerned with what is in and what is out than with the reality of underfunded and overstretched services. The idea that we are part of a conspiracy to medicalise normality will seem frankly laughable as we struggle to protect services for those whose disorders are all too evident under any classification system.

Simon Wessely is a member of the Royal College of Psychiatrists and chair of psychological medicine at King's College London

YES Oliver James, author and clinical psychologist

A student friend of mine once started claiming that she was being controlled by electrical impulses beamed across the city by "authoritarian capitalists". She spent hours in the bath, cleaning herself.

Following her removal to an asylum, her parents arrived to collect her possessions. Nearly all of her (mostly clean) clothes were deemed so "soiled" they would need to be burnt. The room was obsessively cleaned. Her father was a health inspector.

Within the medical model of mental illness, she had inherited genes predisposing her to obsessive rituals and to psychosis. The model does not entertain the possibility that the health inspector's intrusiveness distressed her or, as it turned out, that he had sexually abused her.

Yet 13 studies find that more than half of schizophrenics suffered childhood abuse. Another review of 23 studies shows that schizophrenics are at least three times more likely to have been abused than non-schizophrenics. It is becoming apparent that abuse is the major cause of psychoses. It is also all too clear that the medical model is bust.

In the press release accompanying publication of DSM-5, David Kupfer, who oversaw its creation, states: "We've been telling patients for several decades that we are waiting for biomarkers. We're still waiting." This is an astonishing admission that there are no reliable genetic or neurological measurements that distinguish a person with mental illness.

While there is some evidence that the electro-chemistry of distressed people can be different from the undistressed, the Human Genome Project seems to be proving that genes play almost no part in causing this. Eleven years of careful study of our DNA shows that differences in it do not explain mental illness, hardly at all. If one sibling is anxious or depressed and another is not, at most, differences in DNA can only explain 1-5% of why it is one and not the other.

Of course, some researchers maintain that, given more time (and money), they will still come up with significant results. But off the record, nearly all molecular geneticists admit that it now really does look as if differences in DNA will explain very little.

By contrast, there is a huge body of evidence that our early childhood experiences combined with subsequent exposure to adversity explain a very great deal. This is dose dependent: the more maltreatment, the earlier you suffer it and the worse it is, the greater your risk of adult emotional distress. These experiences set our electro-chemical thermostats.

So does subsequent adult adversity. For instance, a person with six or more personal debts is six times more likely to be mentally ill than someone with none, regardless of their social class: the more debts, the greater the risk.

We need fundamental changes in how our society is organised to give parents the best chance of meeting the needs of children and to prevent the amount of adult adversity.

Britons and Americans have exactly twice the amount of mental illness of mainland western Europeans (23% versus 11.5%). Thirty years of Thatcher and "Blatcher" turned us into a nation of "affluenza"-stricken, shop-till-you-drop, "it could be you", credit-fuelled consumer junkies. Personal debt – a major stressor for adults – rose from £200bn in 1980 to £1,400bn in 2006. After 1979, the amount of mental illness mushroomed.

Forget about genes. We would halve the amount of emotional distress in this country if we had the more equal, relatively cohesive, less debt-ridden political economics of our European neighbours.

Oliver James trained and practised as a clinical psychologist. He is the author of Love Bombing – Reset your Child's Emotional Thermostat