There is no such thing as a 'mugraine', like 'IBS' it is a term which means 'collection of conditions with unknown cause which has a set of similar and overlapping symptoms'. If you look at the symptoms and causes of many 'migraines' you in fact see different causes (some are caused by bright light, some by loud noise, some by different food allergies, some by stress) and a vague set of symptoms which vary a lot between patients. This is why some migraine sufferers respond to 'migraleive' and similar drugs while others do not - they are actually different conditions.

There are many conditons which doctors cannot treat, and I am not talking here about the biggies like cancer or AIDs (which we are getting better at treating, its just that often the treatment is worse than the disease). Mainly this is because we do not understand the underlying mechanism of that disease because the medical profession is reliant on the rather subjective and uninformative process of patient self reporting of symptoms ('What seems to be the problem?' 'I have a headache and stomach ache' 'How bad is the stomach ache?'...). Doctors have got very good at teasing out truth and lies and relevant information from the rather vague information that patients tell them but it is still not a great tool. Sometimes you get a patient with no actual serious symptoms - possibly some minor stress related problems that are clearly not linked to any underlying problem which can be treated more directly. In this case, the best thing you can do is alleviate the stress (and giving a placebo will achieve this) in the hope that this solves the problem. If it doesn't, you can look at more direct intervention.

The old adage is true - medicine really is the process of amusing the patient while the body treats itself.