Post-traumatic stress disorder (PTSD) and migraine often co-occur, but researchers knew relatively little about how or why this happens. A new study in Frontiers in Neuroscience is the first to investigate if the conditions have a common genetic basis. By studying identical twins, where one twin in each pair lives with PTSD or migraines and the other twin does not, the researchers found common genes that may play a role in both conditions. These genes may help to explain why the conditions co-occur, and could reveal new treatment targets for both.