Cognitive behavioural therapy (CBT), which seeks to improve the symptoms of illness by changing patients’ attitudes, thoughts and feelings, often strikes people as flaky. It sometimes seems to suggest the power of mind over matter, chiming both with New Age ideas that a healthy body flows from a healthy spirit and the old-fashioned “pull yourself together” approach to psychiatric medicine.

Few psychiatrists, however, dispute that CBT can be helpful to patients with depression, anxiety and even schizophrenia. Courses seem to change the way that people approach mental illnesses, allowing them to alter their behaviour in constructive fashion.

Now the technique is showing promise in more unlikely fields, too. Several studies have shown that it can improve the prognosis for some cancers, and this week, Professor Trudie Chalder, of King’s College London, announced that it can help people with type 1 diabetes.

Though her study has not yet been peer reviewed or published, Professor Chalder described the results as positive. Not only did subjects report improved attitudes towards their condition, but their blood sugar levels went down, too. She took pains to point out that they were not “thinking themselves better”; CBT instead seems to have empowered people to eat more sensibly and to exercise more, improving their physical condition. But the message was clear: the technique can have tangible benefits in a disorder that has a manifest physiological cause.

Such studies are feeding a growing consensus that CBT has a lot to offer throughout medicine, beyond those conditions in which patients’ thought processes are more obviously involved. Even when diseases have a clear physical cause – a virus, as in HIV, or an auto-immune reaction, as in diabetes or arthritis – psychological factors can have a major effect on outcomes. Compliance with treatment regimens, diet and exercise, and background mental health are often critical to a good prognosis, and CBT can improve all of these. It is decidedly not a treatment that can help only when illness is all in the mind.

That misleading impression, however, still inspires hostility towards CBT among people who might benefit greatly. Chronic fatigue syndrome (CFS) is a case in point. The National Institute for Health and Clinical Excellence has recently recommended CBT and a related strategy, graded exercise, for the condition, on the back of good randomised clinical trials that indicate a benefit. There are no other therapies for CFS with such good evidence in their support, yet some patient groups have reacted with anger.

For these critics, CBT is part of a medical crusade to write off their condition. A prescription that sounds like glorified counselling seems like an allegation of malingering. Yet while the origins of CFS remain obscure, and factors such as infection may be involved, an acknowledgement that psychology may also be implicated does not imply this at all. Even if CFS can be at least partially psychosomatic, such symptoms can still be real and distressing. They deserve to be taken seriously.

Medicine has moved on from the view that only conditions with an unambiguous cause – a virus, tumour or injury – are worthy of attention. The problem comes in finding an appropriate treatment, and nonspecific therapies such as CBT, which help patients to manage their symptoms, are often the best there are.

A recommendation for CBT, too, says nothing about the origins of ill-health. The biology of cancer and diabetes is quite well understood, yet there is evidence that CBT can help and many patients are keen to have it. It is unfortunate that people with CFS do not think likewise. To embrace the one treatment that has been shown to be effective against their illness does not mean it is imaginary.

Mark Henderson is the Science Editor of The Times Dr Copperfield returns next week

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