"Doctors in dispute: What exactly is normal human behaviour?", wrote The Independent, while The Observer said: "Psychiatrists under fire in mental health battle."

These headlines focused on a new version of a major guide to mental health that was published in May 2013 amid a storm of controversy and bitter criticism.

Fourteen years in the writing (and according to one psychiatrist, “thick enough to stop a bullet”) the fifth edition of the American Psychiatric Association's “Diagnostic and Statistical Manual of Mental Disorders” (DSM-5) has been dubbed “The Psychiatrist’s Bible”.

DSM-5 is an attempt to provide doctors with a much-needed definitive list of all recognised mental health conditions, including their symptoms. But with so many gaps in our understanding of mental health, even attempting to do so is hugely controversial.

There are two main interrelated criticisms of DSM-5:

an unhealthy influence of the pharmaceutical industry on the revision process

an increasing tendency to "medicalise" patterns of behaviour and mood that are not considered to be particularly extreme

A brief history of the DSM

The DSM was created to enable mental health professionals to communicate using a common diagnostic language. Its forerunner was published in 1917, primarily for gathering statistics across mental hospitals. It had the politically incorrect title Statistical Manual for the Use of Institutions for the Insane and included just 22 diagnoses.

The DSM was first published in 1952 when the US armed forces wanted a guide on the diagnosis of servicemen. There was also an increasing push against the idea of treating people in institutions.

The first version had many concepts and suggestions that would be shocking to today’s mental health professional. Infamously, homosexuality was listed as a "sociopathic personality disorder" and remained so until 1973. Autistic spectrum disorders were also thought to be a type of childhood schizophrenia.

Because our understanding of mental health is evolving, the DSM is periodically updated. In each revision, mental health conditions that are no longer considered valid are removed, while newly defined conditions are added.

Pharmaceutical influence on mental health diagnoses

Healthcare in the US is big business. A 2011 report estimated that the total US spending on health during that year was $2.7 trillion. This represents 17.9% of the country gross domestic product (GDP). In contrast, NHS spending represents just 8.2% of the UK’s GDP.

However, treating mental health conditions (including dementia) is the highest area of spending within the NHS.

Links and potential conflict of interests between the pharmaceutical industry and the DSM-5 taskforce (the group that revised the manual) are a matter of record. A 2011 article in the Psychiatric Times pointed out that 67% of the task force (18 out of 27 members) had direct links to the pharmaceutical industry.

The DSM-5 taskforce has responded vigorously to these criticisms, pointing out that not only is close co-operation between researchers and industry to be expected, it is also “vital to the current and future development of pharmacological treatments for mental disorders”.

"Medicalising" mental health

Some proposed diagnoses in DSM-5 were criticised as potentially medicalising patterns of behaviour and mood.

These criticisms came to public attention after an open letter and accompanying petition was published by the Society for Humanistic Psychology.

In their letter, a group of psychiatrists argued that they were “concerned about the lowering of diagnostic thresholds for multiple disorder categories, about the introduction of disorders that may lead to inappropriate medical treatment of vulnerable populations, and about specific proposals that appear to lack empirical grounding”.

This was followed by a number of high-profile articles by Professor Allen Frances, whose arguments carry more weight than most, as he was chair of the taskforce for DSMIV-TR (the previous update in 1994). In an article entitled DSM 5 Is Guide Not Bible – Ignore its Ten Worst Changes he highlighted changes to the manual that he argued were examples of over-medicalisation of mental health. These changes included:

Asperger’s syndrome

Disruptive mood dysregulation disorder

Mild cognitive disorder

Generalised anxiety disorder

Major depressive disorder

Asperger’s syndrome

The diagnosis of Asperger’s syndrome has been removed from the DSM-5 and is now part of one umbrella term "Autism spectrum disorder". This is hugely controversial as, according to the ICD-10, those suffering from Asperger’s syndrome have “no general delay or retardation in language or in cognitive development”.

This decision was widely reported in the UK media in 2012.

Disruptive mood dysregulation disorder

Disruptive mood dysregulation disorder (DMDD) is defined by DSM-5 as severe and recurrent temper outbursts (three or more times a week) that are grossly out of proportion in intensity or duration in children up to the age of 18.

This definition is said to be based on a single piece of research, so it is not clear how it might apply to people seeking medical or psychological help for mental health problems in the “real world”.

Prof Frances points out that this diagnosis may “exacerbate, not relieve, the already excessive and inappropriate use of medication in young children”.

Mild cognitive disorder

Mild cognitive disorder (MCD) is defined as “a level of cognitive decline that requires compensatory strategies … to help maintain independence and perform activities of daily living.”

The DSM-5 makes it clear that this decline goes beyond that usually associated with ageing. Despite this, the concept of mild cognitive disorder has been attacked. The main criticism is that there is little in the way of effective treatment for MCD, but if people are diagnosed with the condition it may cause needless stress and anxiety. People diagnosed with MCD may worry that they will go on to develop dementia, when this may not be the case, critics argue.

Generalised anxiety disorder

The "diagnostic threshold" for generalised anxiety disorder (GAD) was lowered in the new version of the manual.

In previous versions, GAD was defined as having any three of six symptoms (such as restlessness, a sense of dread, and feeling constantly on edge) for at least three months. In DSM-5, this has been revised to having just one to four symptoms for at least one month.

Critics suggest that this lowering of the threshold could lead to people with "everyday worries" as being misdiagnosed and needlessly treated.

Major depressive disorder

The most scathing criticism of DSM-5 has been reserved for changes to what constitutes major depressive disorder (MDD).

As you would expect, previous definitions described MDD as a persistent low mood, loss of enjoyment and pleasure, and a disruption to everyday activity. However, these definitions also specifically excluded a diagnosis of MDD if the person was recently bereaved. This exception has been removed in DSM-5.

A wide range of individuals and organisations have argued that the DSM-5 is in danger of "medicalising grief". The argument expressed is that grief is a normal, if upsetting, human process that should not require treatment with drugs such as antidepressants.

How has the DSM-5 been received in the UK?

The reception to the new DSM-5 has been mixed. The British Psychological Society (BPS) published a largely critical response in which it attacked the whole concept of the DSM. It stated that a “top-down” approach to mental health, where patients are made to "fit" a diagnosis is not useful for the people who matter most – the patients.

The BPS said: “We believe that any classification system should begin from the bottom up – starting with specific experiences, problems, symptoms or complaints.

“Since – for example – two people with a diagnosis of ‘schizophrenia’ or ‘personality disorder’ may possess no two symptoms in common, it is difficult to see what communicative benefit is served by using these diagnoses. We believe that a description of a person’s real problems would suffice.”

The UK mental health charity Mind took a more positive approach. The charity’s chief executive, Paul Farmer, said: “Mind knows that for many people affected by a mental health problem, receiving a diagnosis enabled by diagnostic documents like the DSM-5 can be extremely helpful. A diagnosis can provide people with appropriate treatments, and it could give the person access to other support and services, including benefits.”

In defence of the DSM-5

Given the criticism listed above you could be forgiven for thinking that the DSM in general and the DSM-5 in particular has no supporters in the world of mental health. This is not the case. Many mental health professionals are proud to defend the DSM-5 and its principles.

Some may cite the fact that given our uncertain knowledge of mental health, having a diagnostic guide is invaluable for doctors to refer to. While the DSM (and the related ICD system) may be a flawed classification system – subject to biases and lacking empirical proof – it is likely to be better than anything else currently available.

Other attempts to classify mental health conditions, have included:

systems based on brain biology – such as assessing unusual levels of neurotransmitters

systems based on measuring the psychological dimensions of personality (such as extraversion, agreeableness, conscientiousness, neuroticism, openness)

systems based on the development of the mind

While these systems are often elegantly expressed in textbooks, none has succeeded in being robust enough to withstand real-world conditions.

As Prof Frances puts it in an essay on the topic called Psychiatric Diagnosis: “Our classification of mental disorders is no more than a collection of fallible and limited constructs that seek but never find an elusive truth. Nevertheless, this is our best current way of defining and communicating about mental disorders.

“Despite all its epistemological, scientific and even clinical failings, the DSM incorporates a great deal of practical knowledge in a convenient and useful format. It does its job reasonably well when it is applied properly and when its limitations are understood. One must strike a proper balance.”

Many people may have sympathy with the British Psychological Society’s response – which could be briefly summarised as “treat the person not the disease”.

But what happens when it comes to research? If you were running a large randomised controlled trial on hundreds of people with schizophrenia you would need some sort of pre-determined criteria of what constitutes schizophrenia. It would be unfeasible to carry out a full psychological assessment of every individual in that trial.

It is also easy to forget how open to doubt psychiatric diagnoses were in the past. In a landmark 1973 paper by David Rosenhan (On Being Sane in Insane Places), eight people with no history of mental illness feigned symptoms in order to gain admission to mental health facilities. As soon as they did gain entry they then stopped feigning any symptoms, yet none of the staff noticed any change in their behaviour. Embarrassingly enough, many other patients did suspect that these people were "not crazy".

Another study from 1971 found that psychiatrists were unable to come to a shared diagnostic conclusion when studying the same patients on videotape.

Therefore any improvement in the diagnostic framework for mental health, however imprecise it may be, should never be taken for granted.

Conclusion

Our knowledge about the human mind is dwarfed by our understanding of the rest of the body. We have tools that can confirm a diagnosis of a sprained ankle or a damaged lung with pinpoint accuracy. No such tools currently exist to accurately diagnose a "damaged" mind.

It could be that our current models of human psychology could be as flawed as the "four humours" model of medieval medicine.

Criticisms of the DSM-5, such as the issue of medicalising mental wellbeing, are legitimate areas of debate. This debate is to be welcomed if doctors are to appreciate the scale of the challenges of better diagnosing, treating and caring for people with mental health conditions.

These challenges are likely to persist in the decades to come.

Rather than seeing the DSM-5 as the “Psychiatric Bible”, it may be better to think of it as a rudimentary travel guide to a land we have barely begun to explore.