Overuse of medication as risk factor of chronic headache

The international headache society defines headache as chronic if it occurs on more than 15 days per month. The vast majority of patients suffering from chronic headache have medication overuse headache, chronic migraine or chronic tension-type headache. Frequent intake (overuse) of acute headache drugs is probably the most important risk factor leading do the development of medication overuse headache (MOH). The prevalence of MOH reaches approximately 1% of the world's population and shows an increasing trend. Many important studies on medication overuse headache have been published. Some of them investigated the pathophysiology of headache chronification others focused on the evaluation of risk factors. The IHS revised its classification criteria on MOH. Several large population based longitudinal studies clearly demonstrated that overuse of any kind of acute headache medication is the main risk factor leading to the development of chronic headache. Management of MOH remains difficult. The only effective treatment concept remains consequent withdrawal therapy.