Migraine often runs in families and it’s likely that part of the cause is genetic. But nobody knows why some people tend to get attacks while others don’t, or why attacks are especially frequent and troublesome at some times and not others. A few migraine sufferers are able to identify things that reliably trigger an attack. They know, for instance, that, if they eat chocolate or drink a glass of red wine, they will end up with a migraine. But for most people, attacks of migraine come out of the blue and can’t be predicted.