[Multiple sclerosis: cost of the illness].

Economic assessments for multiple sclerosis (MS) first appeared in the nineties. Drug costs were initially marginal before the recent introduction of interferon-beta. To evaluate the burden of MS, economic studies were carried out in addition to specific cost-of-illness studies. Like other chronic illnesses, MS patients can have mild to moderate or severe disabilities. This led to the need for indirect cost analysis. We interrogated the Medline database from 1985 to 2001 to select cost-of-illness studies. We present our findings here by type of methodology used, health care system and level of disability. We found that indirect costs are related to patient age at symptom onset (20-40 years). In most counties, excepting the United Kingdom, hospital costs dominate direct costs. Finally, MS costs are related to the stage of the disease.