All in the mind: the cases that doctors can't explain

Most patients expect a quick diagnosis and cure from their doctor. But what if nothing can be found? What if there is no medical explanation for the symptoms, let alone a cure? More than one in four patients visiting their GP have unexplained pain or symptoms, according to a new report. Other research suggests that up to 50 per cent of primary-care users have symptoms that cannot be tracked down.

And it is not just chronic aches and pains. Sensory loss, walking problems, hallucinations, non-cardiac chest pain, paralysis and seizures are all there, with no apparent cause. Some patients have a history of eight or more unexplained complaints in different parts of their body.

"Medically unexplained symptoms can be related to any body system and most medical specialties. Common symptoms include fatigue, dizziness and pain, although sexual and reproductive problems and abdominal pain, bloating, diarrhoea and constipation are also common,'' says Richard Brown, a psychologist at Manchester University.

According to a new British Medical Journal report, these "heart-sink patients" – a name based on the doctor's reaction to seeing them in the surgery – are a considerable problem. "More than a quarter of primary-care patients in England have unexplained chronic pain, irritable bowel syndrome or chronic fatigue," it says. "And around a third of new neurological outpatients have symptoms thought by neurologists to be not at all or only somewhat explained by disease.''

Medically unexplained symptoms (MUS) are those that cannot be explained by specific illness or injury. Common conditions associated with MUS include irritable bowel syndrome, non-epileptic attack disorder, chronic fatigue syndrome, multiple chemical sensitivity, hyperventilation syndrome and Gulf War Syndrome. For the patient, the symptoms are as disabling as those for which a cause is found. Some patients can suffer for years with chronic pain, while others are bed-ridden.

The reasons why some people have unexplained symptoms are not clear. According to the American Academy of Family Physicians, some may be more sensitive to changes in the way the body works, and are more quick to pick up on functional changes. Stress can also make this sensitivity stronger, and depression and anxiety are common in people with MUS. One study found that almost half of patients with unexplained movement problems had an undiagnosed psychiatric problem, while an Israeli study shows that common additional diagnoses are anxiety, depression, sexual dysfunction and marital problems.

Stress is also a factor in unexplained chest pain, a common reason for costly emergency hospital admission. When researchers at Göteborg University analysed patients, they found that stress at work was associated with a fourfold increased risk of having chest pain for which no explanation could be found. Among women admitted, there was a higher likelihood of depression.

People with unexplained symptoms often overestimate the likelihood of there being a medical cause for them when they see their GPs, according to a study Marburg University in Germany. But healthy people correctly remembered the doctor's estimates as being low.

Among children, anxiety can be behind unexplained symptoms. According to a Royal College of Psychiatrists report, one in 10 children suffer from symptoms for which no medical cause can be found: "In many, these symptoms can be made worse by worries – about school, friendships or family," it said.

So are these "heart-sink" patients really ill? Researchers at the University of Washington Medical School say they can best be understood by making a distinction between disease and illness. Diseases, they say, are the physiological changes associated with organic abnormalities and physical signs. Illness, meanwhile, is the physical or psychological symptoms perceived by the patient. "Patients can have relatively severe diseases, such as heart attacks, yet adapt well and refuse to give up their work; thus, they have disease with little illness. Doctors also encounter patients who appear to be highly disabled despite the absence of any disease. In our culture, we have far more difficulty dealing with the latter.''

The challenge for patients and doctors is how to deal with unexplained symptoms. Although tests can be carried out, negative results often fail to ease concerns. Doctors may also face resistance to idea of psychological or psychiatric treatment because it may be interpreted, wrongly, as a suggestion that the symptoms are imagined or that the patient is mentally unwell.

Yet talking therapy, especially cognitive behavioural therapy (CBT), can work for many people, and may even save lives. At Ben-Gurion University in Israel, doctors took 42 patients whose symptoms could not be medically explained, and gave half of them normal medical care, while the others had biopsychosocial (BPS) therapy. The latter could include lifestyle changes, relaxation techniques and exercise, psychotherapy, CBT and family therapy.

Results show that among those who had the BPS therapy, visits to consultants dropped from an average of 31.8 to 12.6 after one year, while visits to emergency wards declined from 33.5 to 4.1. Mortality rates, too, were lowered in the BPS patients. So if your doctor sends you to CBT for your headaches, don't think he or she is giving you the brush-off.