The unequal geographical distribution of multiple sclerosis is one of its most striking and potentially significant characteristics. The disease occurs with much greater frequency in temperate latitudes and it is particularly prevalent on the island of Orkney, where the prevalence rate is about six times greater than the world average of 30 per 100,000 population (Donnelly 1974). In Great Britain as a whole it is estimated that between 40,000 and 50,000 individuals suffer from the illness, implying a rate of more than twice the world average figure.

Multiple sclerosis is a disease of early and middle adulthood and one which occurs more frequently in females. The disablement consequent upon the complaint varies considerably: from severe paralysis in a few cases to no visually apparent incapacity. It is virtually impossible, however, to estimate precisely the numbers suffering from specific degrees of disability. Similarly generalisations relating to the prognosis of the disease are often misleading because no two patients are affected in exactly the same manner.

The majority experience a relapsing and remitting course and the frequently encountered assumption that multiple sclerosis inevitably leads to rapidly progressive deterioration in physical condition is inaccurate and has given rise to unnecessary pessimism.

Our understanding of multiple sclerosis is in a position today somewhat analogous to that of tuberculosis late last Century. There are a number of specific similarities, such as the presence of precipitating influences in both diseases (e.g. pregnancy) and the intermittent nature of the two complaints. On a broader level, clues relating to the aetiology and epidemiology of the disease continue to emerge but the clearly identifiable cause or causes and an effective form of treatment which will prevent further relapses have yet to be discovered. Yet it seems probable that research work will, in the not too distant future, clarify the different aspects of multiple sclerosis which may well turn out to be a great deal less complex than is implied by the relatively confused state of our current knowledge of the disease.

This paper describes the nature and suspected causes of multiple sclerosis, its prevalence and the variety of therapeutic measures which have been employed. It also examines the social and personal problems generated by the complaint and the implications that they have for its management.