THE definition of bipolar disorder is so broad "almost anyone" suffering emotional problems can be diagnosed with the condition, a prominent psychiatrist has claimed.

In a new book, The Bitterest Pill, Dr Joanna Moncrieff argues that psychiatrists overdiagnose bipolar particularly with people who experience the key symptom of extreme mood swings.

The disorder - which affects a number of Hollywood stars, including actress Catherine Zeta-Jones, comedian Russell Brand and actor Stephen Fry - has become fashionable because "sinister" drug companies have changed the definition to create a larger market for their antipsychotic medication, Dr Moncrieff writes in the edited excerpt from her book published below.

IT WAS 'RIPE FOR EXPLOITATION'

The mostly legal manipulation of public and psychiatric understanding of what has come to be known as bipolar disorder (previously known as manic depression) has been sinister.

The manufacturers of rare antipsychotic medication have set about changing the meaning of this once rare and distinctive condition, expanding its boundaries beyond recognition so that 'bipolar disorder' has become a label that can be attached to a whole myriad of common personal difficulties, who then become legitimate targets for antipsychotic treatment.

An article in the British publication The Psychiatrist entitled I Want To Be Bipolar describes the relatively recent phenomenon of people actively seeking to be diagnosed with bipolar disorder.

Journalist Patrick Strudwick was one of these people, and he described his story in The Times newspaper in 2012.

After the break-down of a difficult relationship in 2003, he threw himself into his work, found that he was sleeping less, and had periods when he felt his mind was racing, he was full of energy and overtalkative.

He researched his problems on the internet and decided he had bipolar disorder.

Although a friend advised him he most probably did not have the condition, he described how he convinced himself and his doctor that he did.

"I want a label for how I'm feeling and drugs to make it stop," he recalled. "I read reams about bipolar disorder.

"Every sensation of the past few months morphed into these descriptions of symptoms. I ignored the ones I don't have."

Patrick's general practitioner referred him to a psychiatrist who was happy to confirm the diagnosis of bipolar disorder and Patrick was started on a drug called Depakote.

He took this for several years until another psychiatrist questioned the diagnosis, and eventually Patrick started to doubt it himself.

Finally tiring of the sedating effects of the drug, he weaned himself off. When he confessed to this episode some years later, two of his friends described how they too had been labelled as having 'bipolar disorder' in the same sort of circumstances.

A few days after The Times article was published, an old friend of mine contacted me with a similar story. Like the author of the article, my friend had been diagnosed with bipolar disorder and treated for several years with the antipsychotic drug Seroquel (quetiapine) after a life crisis.

She had belatedly come to realise that she had been labelled as having a serious, lifelong mental condition, which could have untold consequences for her future.

Bipolar disorder was ripe for exploitation.

Longstanding associations between manic depression and creativity gave the condition a glamorous image, and it was not linked with the intellectual and social deterioration associated with the concept of schizophrenia.

As Patrick's example shows the idea that one's feelings and behaviour constitute an illness or disease can provide a reassuringly concrete explanation for emotional turmoil.

The bipolar epidemic started in the USA in the 1990s when some academics started to suggest that the disorder was under-recognised.

The condition that was originally called manic depression is a rare disorder in which the sufferer becomes aroused and overactive over a sustained period lasting weeks at least and frequently many months.

It is easily recognisable because the individual's behaviour is out of character and often out of control, and it usually leads to admission to a psychiatric unit. Most inpatient facilities in the UK see only a handful of such cases a year.

Bipolar disorder has been transformed from a readily discernible pattern of behaviour to a highly flexible concept that can be applied to almost any individual in some sort of difficulty.

Although all forms of the disorder are proposed to consist of some sort of abnormal variation of mood, there is a world of difference between the sustained periods of heightened arousal, disinhibited behaviour and overactivity characteristic of classical mania, and the periods of increased energy that most people experience from time to time.

There is no research evidence that can confirm that these situations are the same phenomena or that they have the same origins.

As Patrick Strudwick noticed when he attended the local bipolar support group: "The others in the group share stories of kaleidoscopic hallucinations, distinctly inappropriate public nudity and policemen fishing them out of reservoirs.

"My stories did not compare."

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The Bitterest Pills: The Troubling Story of Antipsychotic Drugs, published by Palgrave Macmillan.