Both migraine and motion sickness may be due to low brain levels of serotonin.

Scientists believe that low levels of a brain chemical called serotonin may make people susceptible to developing migraine headaches. Many people with migraine also have a problem with motion sickness, but it is not clear why this might be. We know that many drugs to treat motion sickness increase brain levels of serotonin, an important brain chemical. It is possible that low brain levels of serotonin may also be responsible for motion sickness. In this issue of Neurology, Drummond reports on a study that evaluated whether low brain levels of serotonin trigger motion sickness in people with and without migraine. More information about migraine can be found on the next page.