Migraine-associated risks and comorbidity.

This review reports important co-morbid conditions of migraine and resulting consequences for the choice of acute and preventive treatments of migraine. Comorbidity in this context means the occurrence of two diseases in an individual beyond chance. The basis of comorbidity can be genetic and/or based on common environmental factors. In some cases, the temporal relationship is unclear and one disease can cause another disease. In order to prove a real comorbidity, large-scale and well-performed epidemiological studies are required.