Dependence scores predict prognosis of medication overuse headache: a prospective cohort from the Akershus study of chronic headache

Medication overuse headache (MOH) is a chronic headache that is common in the general population. It has characteristics similar to drug dependence, and detoxification is established as the main treatment. The majority of MOH cases are in contact with general practitioners. Our objective was to investigate whether the Severity of Dependence Scale (SDS) score could be used as predictor for the prognosis of MOH in the general population. In a cross-sectional epidemiological survey, an age- and gender-stratified sample of 30,000 persons 30 to 44 years of age was recruited via a posted questionnaire. Those individuals with self-reported chronic headache (≥15 days per month) were interviewed by neurological residents at Akershus University Hospital, Oslo. The International Classification of Headache Disorders was used. Those with MOH were re-interviewed by telephone 2 to 3 years after the initial interview. SDS scores and medication information were collected at baseline and follow-up. The main outcomes were SDS scores, termination of MOH and chronic headache from baseline to follow-up. We found the predominant overused analgesics in this sample to be simple analgesics. At follow-up, 65% of participants no longer had medication overuse, and 37% had changed to episodic headache (<15 days per month). The SDS score at baseline successfully predicted improvement for primary MOH, but not secondary MOH. The SDS scores decreased slightly from baseline to follow-up in those who stopped medication overuse, but were still significantly higher than in subjects with chronic headache without medication overuse at baseline. We conclude that the SDS score can predict successful prognosis related to detoxification of primary MOH but not in secondary MOH.