RT Journal Article SR Electronic T1 Hypnic Headache JF Practical Neurology JO Pract Neurol FD BMJ Publishing Group Ltd SP 144 OP 149 DO 10.1111/j.1474-7766.2005.00301.x VO 5 IS 3 A1 Stefan Evers A1 Peter J. Goadsby YR 2005 UL http://pn.bmj.com/content/5/3/144.abstract AB INTRODUCTION Hypnic headache is a rare episodic headache syndrome first described by Raskin in 1988. It has also been called ‘clockwise headache’ or ‘alarm-clock headache’ (Newman et al. 1990). More than 80 similar cases have been reported and our recent systematic review of all published cases described the typical clinical picture and treatment options (Evers & Goadsby 2003). Characteristically, many times a month, a dull pain wakens the patient from sleep, it lasts for more than 15 min, tends to start over the age of 50, but it does not have the autonomic features of cluster headache (Table 1).So far everyone has assumed that hypnic headache is an idiopathic headache disorder. Diagnostic criteria were first proposed in 1997 (Goadsby & Lipton 1997) and hypnic headache is now included in the revised version of the headache classification of the International Headache Society (IHS) (Headache Classification Subcommittee 2004). CLINICAL FEATURES A