AIMS - To estimate the proportion of new patients with medically unexplained symptoms (MUS) that present to neurology out -patient services and to examine the impact of such symptoms on the patients in terms of disability, distress and outcome. Methods- Historical (MUS from 2 000 BC to 1965), narrative (non -neurological MUS) and systematic (MUS in neurology 1960 - 2000) reviews of the previous literature were conducted. A prospective cohort study of 300 newly referred out- patients was carried out in the regional neurology service in Lothian, Scotland. Patients were examined at the time of initial presentation and re- examined eight months later. Both primary and secondary care case -note were reviewed at follow up. Measures- Neurologists rated degree to which the patients' symptoms were explained by organic disease. Health status was measured using the SF -36. Anxiety and depressive disorders were examined using the PRIME MD and HAD. Outcome was measured on a Clinical Global Improvement (CGI) scale.RESULTS - The historical review of the literature found that MUS have been described since the first written texts of medicine. The narrative review showed that MUS affected both sexes, all ages, and all cultures. The systematic review of MUS in neurology found that between 30-40% of cases in neurology had MUS and the rate of misdiagnosis was less than 5%. In the field of neurology there was no information on disability, limited information on co- morbid anxiety and depressive disorders, and outcome studies were confined to conversion hysteria only. In the prospective cohort study 30% of new patients presenting to neurology out -patient clinics had MUS. They were as physically disabled by their symptoms as those with neurological disease were by theirs. They suffered from increased levels of pain and increased rates of anxiety and depression. At eight months follow up more than half the MUS patients were `just the same' or `worse'. There were no cases where unexpected neurological disease was diagnosed during the follow up which explained the patient's presenting symptoms. The patients with MUS had had multiple referrals to other specialist services as a result of MUS.CONCLUSIONS - One third of new referrals to general neurology clinics have medically unexplained symptoms. These patients are disabled and distressed. Over half of these patients remain symptomatic at eight months follow up
