It has been previously reported that a substantial proportion of newly referred

neurology outpatients have symptoms that are unexplained by disease. There has however been controversy about how often such patients subsequently develop a disease diagnosis that, with hindsight, explains these symptoms. Our aim was to determine in a large sample of new neurology outpatients: (a) what proportion had symptoms unexplained by disease and their diagnoses; (b) how often a neurological disorder emerged which with hindsight explained the original symptoms.

The Scottish Neurological Symptom Study (SNSS) An 18 month prospective cohort study.

Secondary care NHS neurology clinics throughout Scotland UK

3781 primary care patients referred to neurology outpatient clinic (91% of those eligible).

1) The proportion assessed by the neurologists as having symptoms ‘not at all’ or only ‘somewhat explained’ by organic disease and the neurological diagnoses in these patients, 2) The frequency of an unexpected new diagnosis at 18 months which with hindsight, may have explained the original symptoms (according to the primary care physician, neurologist and consensus rating).

1144 patients (30%) were rated as having symptoms unexplained by organic disease.The most common categories of diagnosis in this group were: (a) organic neurological disease but with symptoms unexplained by it (26%); (b) headache disorders (26%) and (c) conversion symptoms (motor, sensory or non-epileptic attacks) (18%). At follow up, (mean 19 months), only 4/1030 patients (0.4%) had an organic disease diagnosis that was unexpected at initial assessment and plausibly the cause of the patients’ original symptoms. Eight patients had died at follow up; five with initial diagnoses of non-epileptic attacks.

One third of new neurology outpatients have symptoms that are unexplained by organic disease. Such patients rarely develop a new organic disease that could explain their original symptoms.