Migraine: intelligence, social class, and familial prevalence.

Groups of individuals with headache, unilateral headache, and migraine, and a fourth group who had not had a headache in the previous year, were identified by questionnaire from a random sample of adults in the general population. Intelligence and social class were assessed in about 400 individuals. There was no evidence that individuals with migraine were more intelligent or of higher social class. There was, however, a suggestion that the more intelligent individuals with migraine, and those in social classes I and II, were more likely to consult a doctor for their headaches. This trend might explain the origin of the hypotheses associating migraine with intelligence and with social class.Random samples of individuals with migraine with headache and without headache in the previous year were the probands for a family study. There were 524 first-degree relatives over 21 years of age who lived in South Wales. Headache histories, obtained "blindly" from over 99% of these relatives with a standard questionnaire, were classified as migraine, possible migraine, headache, or without headache in the previous year. The prevalence of migraine in the families of the migrainous probands was nearly twice as high as the prevalence in the other families, but this difference was not statistically significant. It is suggested that family history should not be included in the definition of migraine and that heredity is much less important in migraine than is usually supposed.