Migraine (UK: /ˈmiːɡreɪn/, US: /ˈmaɪ-/) is a complex neurological disorder characterized by episodes of moderate-to-severe headache, most often unilateral and generally associated with nausea, light sensitivity and sound sensitivity. Other symptoms may include vomiting, unusual pain, dizziness, and cognitive dysfunction. Some people with migraine experience aura, a period of sensory disturbance at the onset of a migraine attack.
Although primarily considered to be a headache disorder, migraine is highly varied in its clinical presentation and is better thought of as a spectrum disease rather than a distinct clinical entity. Disease burden can range from episodic discrete attacks to chronic disease. Incidence of migraines may increase over time, evolving from episodic migraine to chronic migraine. Overuse of acute pain medications may hasten this process and is a risk factor for developing medication overuse headache.