The clinical and public health implications and risks of widening the definition of chronic migraine.

Defining chronic migraine on the basis of headache frequency alone does not account for clinical and pathophysiological aspects, as well as for the impact of chronic migraine in terms of disability and quality of life. Moreover, it is potentially harmful for patients in terms of allocation of resources. These issues are discussed in the present manuscript, and we support the idea of defining high frequency episodic migraine as an independent entity as a viable path to follow.