Abstract
Migraine and tension-type headache are prevalent clinical disorders associated with significant burden of disease. Despite extensive research and the recent attempt by the International Headache Society (IHS) to operationalise headache diagnoses, controversy exists over whether migraine and tension-type headache are discrete entities or sit at the opposite ends of a "pain severity" continuum. The primary aim of the present study was to determine whether physical and/or psychological measures could differentiate between subtypes of primary headache (migraine, tension-type headache, and "combined" migraine and tension-type headache) in a representative birth cohort. At age 26, the headache status of Study members (based on IHS criteria) was determined. Historical records were examined to ascertain potential physical (perinatal complications, neurological problems, and injuries to the head, neck or back) and psychological (childhood and adolescent behaviour problems and mental health concerns, personality during late adolescence, and mother's mental health) correlates of headache. Migraine at age 26 was predicted by anxiety in childhood, maternal headache, anxiety disorders from ages 11 to 18, and stress reactivity and harm avoidance personality traits at age 18. Tension-type headache at age 26 was predicted by neck or back injury and lower levels of antisocial behaviour in childhood, anxiety disorder and low scores on the personality trait of aggression at age 18. Combined headache was predicted by major depression at age 15 and 18 as well as poor maternal mental health (including headache). Perinatal complications, neurological disorders or concussion did not predict headache status at age 26. These results suggest that, not only are migraine and tension-type headache distinct disorders with different defining characteristics, but also that combined headache may be a third entity with a distinct etiology. These findings have implications for headache research and treatment.