PERIODIC MOOD-CHANGES We have already spoken of the affective concomitants of common migraines--elated and irritable prodromal states, states of dread and depression associated with the main phase of the attack, and states of euphoric rebound. Any or all of these may be abstracted as isolated periodic symptoms of relatively short duration--some hours, or at most two or three days, and as such may present themselves as primary emotional disorders. The most acute of these mood-changes, generally no more than an hour in duration, usually represents concomitants or equivalents of migraine aura. We may confine our attention at this stage to attacks of depression, or truncated manic-depressive cycles, occurring at intervals in patients who have previously suffered from attacks of undoubted (classical, common, abdominal, etc.) migraine.