Outcome of Chronic Daily Headache or Chronic Migraine.

Chronic daily headache (CDH) is a common neurological condition that affects 1-4% of the general population. Recent epidemiological studies have shown that CDH is mainly represented by chronic migraine (CM). Owing to the frequent headaches, associated symptoms, and comorbid conditions associated with CDH/CM, disability, quality of life (QoL), economic burden, and treatment outcome have become important personal and social issues. There have been several studies assessing the disability, QoL, and economic burden associated with CDH/CM. These studies, conducted in different settings, consistently reported significantly higher disability and economic burden and lower QoL among CDH/CM patients compared to patients with episodic headache (EH) or episodic migraine (EM). Treatment outcome of CDH/CM is often poor. In this review, we describe and summarize the results of relevant studies performed to date.