Psychiatry divided as mental health ‘bible’ denounced
The world’s biggest mental health research institute is abandoning the new version of psychiatry’s “bible” – the Diagnostic and Statistical Manual of Mental Disorders, questioning its validity and stating that “patients with mental disorders deserve better”. This bombshell comes just weeks before the publication of the fifth revision of the manual, called DSM-5.
On 29 April, Thomas Insel, director of the US National Institute of Mental Health (NIMH), advocated a major shift away from categorising diseases such as bipolar disorder and schizophrenia according to a person’s symptoms. Instead, Insel wants mental disorders to be diagnosed more objectively using genetics, brain scans that show abnormal patterns of activity and cognitive testing.
This would mean abandoning the manual published by the American Psychiatric Association that has been the mainstay of psychiatric research for 60 years.
The DSM has been embroiled in controversy for a number of years. Critics have said that it has outlasted its usefulness, has turned complaints that are not truly illnesses into medical conditions, and has been unduly influenced by pharmaceutical companies looking for new markets for their drugs.
There have also been complaints that widened definitions of several disorder have led to over-diagnosis of conditions such as bipolar disorder and attention deficit hyperactivity disorder.
Now, Insel has said in a blog post published by the NIMH that he wants a complete shift to diagnoses based on science not symptoms.
“Unlike our definitions of ischaemic heart disease, lymphoma or AIDS, the DSM diagnoses are based on a consensus about clusters of clinical symptoms, not any objective laboratory measure,” Insel says. “In the rest of medicine, this would be equivalent to creating diagnostic systems based on the nature of chest pain, or the quality of fever.”
Insel says that elsewhere in medicine this type of symptom-based diagnosis been abandoned over the past half-century as scientists have learned that symptoms alone seldom indicate the best choice of treatment.
To accelerate the shift to biologically based diagnosis, Insel favours an approach embodied by a programme launched 18 months ago at the NIMH called the Research Domain Criteria project.
The approach is based on the idea that mental disorders are biological problems involving brain circuits that dictate specific patterns of cognition, emotion and behaviour. Concentrating on treating these problems, rather than symptoms is hoped to provide a better outlook for patients.
“We cannot succeed if we use DSM categories as the gold standard,” says Insel. “That is why NIMH will be reorienting its research away from DSMcategories,” says Insel.
Insel is aware that what he is suggesting will take time – probably at least a decade, but sees it as the first step towards delivering the “precision medicine” that he says has transformed cancer diagnosis and treatment.
“It’s potentially game-changing, but needs to be based on underlying science that is reliable,” says Simon Wessely of the Institute of Psychiatry at King’s College London. “It’s for the future, rather than for now, but anything that improves understanding of the etiology and genetics of disease is going to be better [than symptom-based diagnosis].”
Michael Owen of the University of Cardiff, who was on the psychosis working group for DSM-5, agrees. “Research needs to break out of the straitjacket of current diagnosis categories,” he says. But like Wessely, he says it is too early to throw away the existing categories.
“These are incredibly complicated disorders,” says Owen. “To understand the neuroscience in sufficient depth and detail to build a diagnosis process will take a long time, but in the meantime, clinicians still have to do their work.”
David Clark of the University of Oxford says he’s delighted that NIMH is funding science-based diagnosis across current disease categories. “However, patient benefit is probably some way off, and will need to be proved,” he says.
The controversy is likely to erupt more publically in the coming month when the American Psychiatric Association holds its annual meeting in San Francisco, where DSM-5 will be officially launched, and in June in London when the Institute of Psychiatry holds a two-day meeting on the DSM.
This is especially important because many of these groupings of symptoms can actually have different underlying causes in different cases. For instance, I recently read an article where a therapist had found that a significant portion of ADHD cases were actually the result of sleep disorders, and responded to sleep therapies after the usual treatments for ADHD had failed.
Depression is similarly complex, and can be caused by a number of different brain chemistry imbalances. Focusing on the actual brain chemistry rather than the symptoms could take a huge amount of the trial and error out of anti-depressant prescription.