Migraine headaches are a common cause of headache affecting up to 16% of the general population. Likewise, tension headaches are even more common affecting about 40 % of the population. Women are more commonly afflicted than men. Sometimes people with mixed tension migraine have features of both types of headaches and it is difficult to differentiate which symptoms are migrainous and which are tension related. This may be a continuum with a varied clinical spectrum.

Common triggers for these headaches are hormonal changes, dietary factors, environmental factors, sensory stimuli and stress. Examples include too much or too little sleep; missed or delayed meals; menstruation; alcohol; food and food additives; chemical and drug ingestion and withdrawal; light glare; and odors.