Migraine is a common episodic disorder with considerable impact on ind
ividuals and society. Migraine occurs with the highest prevalence betw
een the ages of 25 and 55 years, potentially the most productive perio
d of life. Severe migraine can lead to disruption of work, family and
social life, the long term consequences of which may affect quality of
life. The direct costs of migraine (due to medical care) are small co
mpared with the indirect costs caused by absence from work and reduced
productivity. Population-based studies are required to assess inciden
ce, prevalence and distribution of the disease. These studies also rev
eal that migraine is currently underdiagnosed and undertreated. The cu
mulative impact of migraine on individuals produces the burden of illn
ess on society. Measuring the severity of migraine is important in und
erstanding the extent of the burden of migraine on the individual and
on society. Measures of severity may be useful as predictors of disabi
lity and healthcare use. These measures may also be useful in assessin
g the need for patient care and treatment and help target those more d
isabled by migraine. Identifying and treating appropriate patients sho
uld reduce the impact of migraine on the individual and the burden of
migraine on society.