[Stress and migraine]

The link between stress and migraine is complex. In its recent conception, stress is viewed as a transactional process between an individual and his-her environment in which the individual makes a response to an internal or external constraint. This paper reviews the evidence in favor of a relationship between stress and migraine. Many studies show that 50 to 80% of patients report stress as a precipitating factor for their migraine headaches. Many authors have suggested that acute stress can provoke biological modifications lowering the threshold of the individual's susceptibility to a migraine attack. It has also been shown that the incidence of migraine is higher when stress scores are higher in the previous year. This suggests that as well as being a precipitating factor of crisis, stress could also be a precipitating factor of illness in susceptible individuals. Moreover, stress can trigger migraine chronification. This has been shown in many retrospective studies and in one prospective study. Hyperalgesia and central sensitivity to pain induced by chronic stress can partly explain this phenomenon. Many retrospective studies also show that adverse events during childhood, like sexual and physical abuse, are more frequent in migraineurs than non-migraineurs. Nevertheless, there is no prospective study allowing considering a causal link between childhood abuse and migraine in adulthood. Another point that will be tackled is the comorbidity between stress related psychiatric disorders, such as post-traumatic stress disorder, and migraine. Here again, many studies conducted in huge samples from the general population are convincing. All that leads to propose stress management therapies to migraineurs. Randomized control trials and meta-analyses have shown that relaxation therapies, biofeedback and stress management cognitive behavioral therapies are effective in migraine prophylaxis, above all in children. The use of these therapies is of particular interest in association with pharmacological treatments in patients with frequent crises. However, the majority of the studies have poor methodological standards. Nevertheless, stress management therapies are proposed as prophylactic treatment in the French recommendations for migraine management.