Fig. 1. Distribution of headaches diagnosed according to ICHD-3β. Headache attributed to a substance or its withdrawal (ICHD-3β code 8., 5.2%) consisted of headache attributed to the use of or exposure to a substance (ICHD-3β code 8.1, 0.74%) and medication overuse headaches accompanied by primary headaches (ICHD-3β code 8.2, 4.43%). ICHD-3β indicates International Classification of Headache Disorders third edition, beta version: 1, Migraine; 2, Tension-type headache; 3, Trigeminal autonomic cephalalgias; 4, Other primary headache disorders; 5, Headache attributed to trauma or injury to the head and/or neck; 6, Headache attributed to cranial or cervical vascular disorder; 7, Headache attributed to non-vascular intracranial disorder; 8, Headache attributed to a substance or its withdrawal; 9, Headache attributed to infection; 10, Headache attributed to disorder of homoeostasis; 11, Headache or facial pain attributed to disorder of the cranium, neck, eyes, ears, nose, sinuses, teeth, mouth or other facial or cervical structure; 12, Headache attributed to psychiatric disorder; 13, Painful cranial neuropathies and other facial pains; 14, Other headache disorders.