By Michelle Roberts
BBC News health reporter
Scientific advances such as scanners that see into the brain and powerful mind-altering drugs make it tempting to give a diagnosis to things society terms "mental illnesses".
Psychiatric disorders do not fit into neat boxes
But we should resist from using psychiatric labels because there is no clear division between madness and sanity, experts argue.
To label someone as schizophrenic, for example, falsely groups people with a wide range of problems together.
Followers of psychiatric phenomenology - the study of lived experience in mental illness - say it is time to take a step back.
Doctors do acknowledge that giving psychiatric diagnoses can provide important information to the clinician, therapist, patient, and family, relevant to prognosis, treatment planning and the course of the illness.
However, Professor Paul Mullen, professor of forensic psychiatry at Monash University, Australia, says this labelling has gone too far.
At the turn of the 20th Century, doctors relied as much on what a patient said they were experiencing as they did on piecemeal symptoms to work out what course of action, if any, to take.
But now science has outstripped this, meaning doctors look to books containing check lists of symptoms to decide how to classify and treat a given individual's "disorder".
Professor Mullen said: "At some time towards the end of the 19th Century and the beginning of the 20th Century there was a real effort to make sense of the whole domain of madness.
"They tried to separate it out into what was meant to be temporary categories so that they would allow more precise development of scientific investigations and treatments.
"What has happened in the last 100 years is these concepts became verified and they were turned into themes with operational definitions."
One size does not fit all
So you have a menu that tells you what schizophrenia is, for example. But this does not take account of subtleties and variation from patient to patient, he said. "It has none of the recognition that schizophrenia is not a disorder but a wide range of conditions having a variety of different contributions."
Hinckley is wrestled to the ground after firing shots at the president
He said going by the rule book was madness and often leads to confusion and problems, including misdiagnosis and incorrect treatment.
Professor Mullen said a famous example of confusion was the case of John Hinckley, the man who shot the then US President Ronald Reagan in 1981.
When he was tried in court, psychiatrists ran into problems when trying to categorise Mr Hinckley's motivation.
It transpired that Mr Hinckley was obsessed with actress Jodie Foster. He believed he could win Miss Foster's attention, and ultimately her affection, by shooting Mr Reagan and hence becoming famous himself.
Although Mr Hinckley was found not guilty of attempted murder by reason of insanity, psychiatrists were unable to categorise him as having "erotomania" - a delusional, romantic preoccupation with a stranger, often a public figure - because he did not meet one of the strict diagnostic requirements. He did not believe Ms Foster was deeply in love with him.
Professor Richard Bentall, professor in experimental clinical psychology at the University of Manchester, agrees.
He said: "The idea that there is a clear division between 'mad' and 'sane' people, and that distinct psychiatric categories like 'schizophrenic' actually exist, is resulting in the mass-application of treatments which, while benefiting some, are very harmful to others.
"And because psychiatric patients are seen as having a biological brain illness which affects their rationality, they are not usually allowed a say in the matter."
He said that identifying and addressing the problems the sufferer, rather than the psychiatrist, perceives creates an understanding of each person's condition which is far more scientific, humane and effective than a blanket diagnosis.
"It also allows us to identify people at risk of psychological breakdown earlier, and keep them out of the traditional cycle of diagnosis and treatment."
Even proponents of phenomenology say there is a line to be drawn with this approach.
A dilemma arises when the individual has no insight into their psychiatric disturbance and does not think that what they are experiencing or their behaviour is a problem, but others do.
A big issue is how to deal with people who are violent.
For example, a person's behaviour may threaten their own safety or that of others.
On the one hand the individual does not want or think he or she needs treatment. On the other hand their loved ones or society in general thinks or insists that they do need and have to have help.
Professor Bill Fulford, professor of philosophy and mental health at the University of Warwick and a consultant psychiatrist in Oxford, said sometimes intervention against a person's wishes may be necessary.
Experts will continue the debate surrounding psychiatric phenomenology at the Institute of Psychiatry, London on September 5 and 6, 2005.