Health: There may be more to your clicking jaw: Chronic facial pain often has no obvious cause. Now, says Denise Winn, researchers are close to an explanation

During the past three years, Gina Whitelock became increasingly aware of a clicking noise in her jaw. It began to hurt whenever she opened her mouth. She reached the point where the pain ruled her life. 'It was on my mind 24 hours a day. I'd think: 'I can't eat an apple or have my dinner and I can't open my mouth to speak.' I was also embarrassed that people might hear me clicking.'

Her dentist could not find the cause and referred her to the facial pain clinic at the Eastman Dental Hospital in north London. Ms Whitelock is lucky. She was referred quickly to the Eastman. Thousands suffer from facial pain for which there seems to be no organic cause. About 800 people are referred every year to the clinic, by which time they have usually each seen between two and 30 other specialists, including dentists, ear, nose and throat surgeons, neurologists and neurosurgeons. Many have needlessly had teeth removed or nerves frozen in the search for a cure. Countless others are dismissed as neurotic nuisances.

Facial pain is different from classic neuralgia because it seems to arise from blood vessels, muscles and joints rather than from a disturbance in sensory nerves. Some people suffer a dull ache and a 'sticking and clicking' feeling in the jaw joint; some feel a pain that is like toothache; others a burning pain in the gums, tongue and lips, a dry mouth sensation (despite plenty of saliva) and disturbed taste. Often people complain of discomfort in the way their teeth meet together, which affects their bite. Chronic facial pain may develop at any age, even during childhood.

'People first describe chronic facial pain as unbearable,' says Dr Charlotte Feinmann, a liaison psychiatrist based at University College London and attached to the Eastman Dental Hospital. 'However, when we get them to rate their pain, they actually say it is nagging. It is a pain that badly affects their quality of life but, unlike severe arthritis, doesn't incapacitate them and doesn't show. So they fear being seen as malingerers. And if doctors say they don't know what is wrong with them, they worry more, which only increases the pain.'

Stress appears to be the main trigger - both positive or negative stressful life events or persistent stresses such as marital or work problems - although patients often resist this explanation at first. 'They think you are saying their pain is imaginary, but it is very real indeed,' Dr Feinmann says. In children, the pain may be 'learnt' at home if one or both parents suffer chronic pain problems.

Drugs are not usually a long-term solution to chronic pain, but the situation is different with stress-

related facial pain. Work carried out by Dr Feinmann and Professor Malcolm Harris, maxillofacial surgeon at the Eastman, has shown that antidepressants can work as an analgesic in patients who are not depressed. But whereas a constant dose and a build-up is required before they have an effect on depression, as a painkiller they work more quickly and in smaller or intermittent doses. Recent scientific work at the Eastman has shown that people with stress-related facial pain have lower levels of the chemical conjugated tyramine sulphate - a metabolic defect shared with patients who are clinically depressed.

But antidepressants are not the complete solution. When Dr Feinmann followed up 71 patients four years after they had been prescribed these drugs for facial pain, she found 69 per cent were pain-

free, but the rest were still suffering. Just over a quarter took antidepressants intermittently for flare-ups of pain. Those who complained of other symptoms, such as migraine or irritable bowels, were more likely to have prolonged facial pain. Those who could not accept that stress was a significant factor in their pain were the least likely to do well.

'They think the implication is that they are psychiatric cases. Or they may sometimes receive too small a dosage from their GPs to be useful. Antidepressants can stimulate appetite and lead to weight increase, which also puts many people off,' Dr Feinmann says.

She feels that lifestyle changes are as important as the drug, even for patients who take the antidepressants. She helps people examine the stresses in their lives. 'I don't know what the effect is if antidepressants are prescribed without the counselling,' she says. But this is what she is hoping to find out in a study, funded by the Department of Health, for which she and Dr Shirley Pearce, senior lecturer in clinical psychology at University College London, are recruiting subjects. People are randomly assigned to one of four treatment groups - antidepressants alone, placebo alone, antidepressants and cognitive behavioural therapy, or placebo and cognitive behavioural therapy.

'There is evidence that you can only attend to a certain amount of information at one time. Shifting the focus of attention away from the mouth or the face by imagining something pleasant can be useful,' Dr Pearce says. She makes sure people choose their own pleasant scene rather than guiding them through one of her own imagining. 'I once gave someone the image of walking through the countryside and noticed she became more and more tense instead of more relaxed. When I asked what was wrong, she said, 'There's a bee behind my head and I've got a phobia about bees.' '

Dr Pearce also says it is reasonable to 'fall apart' every so often and give in to the pain. 'It doesn't mean that none of the cognitive strategies will ever work again.'

Gina Whitelock has found the process enormously useful. 'The pain is still there, but I've learnt to cope. I drive a van delivering car spares, so I had plenty of time to think when at work. Now, instead of thinking, 'Oh God, I've got that pain', I think about Christmas, holidays, what I'll do when I get home or imagine a lovely island.

'I know I must keep myself busy. If I find myself with time on my hands, I put my relaxation tape on or decide to do some gardening or visit my sister. It has done me the world of good. Before, I thought of my pain all the time.'

Dr Feinmann and Dr Pearce are hoping that if cognitive strategies are shown to be useful, alongside antidepressants, they could be made more available to patients in dental clinics and save an awful lot of referrals and unnecessary treatment. 'Once you are in the hospital system, you get extensively investigated,' Dr Feinmann says.

'Patients feel a great need to have something done and for doctors and surgeons to do something. That can mean children put in CAT scanners for their brains to be looked at and whole families getting agitated - all for nothing.' For information about the research project: Dr Feinmann, Department of Maxillofacial Surgery and Oral Medicine, Institute of Dental Surgery, Eastman Dental Hospital, 256 Gray's Inn Road, London WC1X 8LD.

(Photograph omitted)