Brain abnormalities have been found in the brains of those who suffer migraines.
Researchers in Italy found that the brain structure of those with migraines may be different than those who do not suffer the bad headaches.
The study used MRI machines to look at the brains of migraine sufferers.
Those who had the headaches showed a thinner and smaller cortex - the outer layers of the brain - than those without migraines.
"For the first time, we assessed cortical thickness and surface area abnormalities in patients with migraine, which are two components of cortical volume that provide different and complementary pieces of information," said Massimo Filippi, at the University Vita-Salute's San Raffaele Scientific Institute in Milan, in a statement.
"Indeed, cortical surface area increases dramatically during late fetal development as a consequence of cortical folding, while cortical thickness changes dynamically throughout the entire life span as a consequence of development and disease."
The new findings add to theories that suggest not only do those with migraines have brains that function differently, they also look different.
The research may also help target where the pain from the headache is originating from.
About 11 percent of people in the world have had a migraine in the last year.
The findings were published in the journal Radiology.