Headaches in medical school students.

Medical students of the Instituto de Ciências Biomédicas 'Abel Salazar' at the University of Oporto were interviewed using a structured headache questionnaire in order to assess the prevalence and characteristics of headaches in a young adult university population. This was the first population-based study of headaches in Portugal. 491 students were questioned. The parameters evaluated included age, sex, headache characteristics (frequency, localization, severity, duration), premonitory and associated symptoms and family history. Headaches were classified using the Ad Hoc Committee (1962) and the International Headache Society (1988) criteria. There was a high prevalence of overall headaches in this young population. The results of the application of these two types of criteria to the same population showed for the most prevalent forms, migraine and tension-type headaches, a prevalence that depends on the classification adopted and the number of criteria items considered. If all (9 items) were used, the statistics obtained for migraine were 6.9% (Ad Hoc) and 6.1% (IHS), an insignificant difference, and for tension-type headache 14.3% (Ad Hoc) and 16.0% (IHS), which corresponds to a significant difference (p = 0.0129, McNemar test). It is concluded that IHS classification criteria identify less cases of migraine and more cases of tension-type headaches, which means a higher specificity for migraine and a higher sensitivity for tension-type headache.