Medication overuse headache (MOH) is defined as a headache 15 or more days per month, associated with the overuse of acute headache medications. This study evaluated headache related disability in MOH and identified predictors for successful self-detoxification.

This large, cross-sectional population-based study included 30，000 patients, ages 30 to 44 years, drawn from the general population in Norway. Potential subjects included 935 persons with self-reported chronic headache, of whom 633 were interviewed by a physician experienced in the treatment of headaches.

During the interviews, information was given about the role of medication overuse in chronic headaches, informing the patient that in some cases reducing the medication could improve their symptoms. Successful selfdetoxification was defined as medication withdrawal and reversion to episodic headache. After the interview, patients completed questionnaires including information on socio-demographics, height, weight, smoking status, medication overuse, headache frequency and psychological symptoms. All were given the migraine disability assessment (MIDAS) to measure headache related disability. Interviews were conducted an average of 1.5 years later to reassess for medication overuse headaches. Of the initial group, 108 were available for follow-up. Of those, 44 were free of MOHs, 38 were described as detoxified, but still had chronic headaches and 25 still had MOHs. Only those cured of MOH had a significant reduction in headache intensity. In a multivariate, linear regression, variables positively associated with a high headache frequency included being without a migraine at baseline (P＝0.009), a high baseline headache frequency (P＝0.023), and high baseline psychological distress (measured by the Hopkins Symptom Checklist 25)．

This study of patients with medication overuse headaches found that these headaches cause substantial disability and that self-detoxification could lead to a reduction in headache frequency and disability.