Objective: To evaluate the Severity of Dependence Scale (SDS) in people with primary chronic headache and analyse the pattern of medication overuse.
Design: Cross sectional epidemiological survey. A posted questionnaire screened for chronic headache. Neurological residents interviewed those with self-reported chronic headache. The International Classification of Headache Disorders was used. Split file methodology was employed for data analysis.
Setting: Akershus University Hospital, Oslo, Norway.
Participants: A random sample of 30 000 people, aged 30–44 years, from the general population of Akershus County, Norway. 405 people had primary chronic headache.
Main outcome measure: SDS score in those with and without medication overuse.
Results: The screening questionnaire response rate was 71% and the participation rate of the interview 74%. Among 405 people with primary chronic headache, 95% had chronic tension-type headache, 4% had chronic migraine and <1% had other primary chronic headaches. Of 386 persons with chronic tension-type headache, 44% had medication overuse and 47% had co-occurrence of migraine. Simple analgesics, combination analgesics, triptans, ergotamine, opioids and a combination of acute medications were overused by 65%, 27%, 4%, <1%, 1% and 2% of people, respectively. The mean SDS score was significantly higher in those with than in those without medication overuse (5.6 vs 2.7; p<0.001).
Conclusion: The SDS questionnaire detects medication overuse and dependency-like behaviour in persons with primary chronic headache.
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Competing interests: None.
Funding: This study was supported by grants from the East Norway and South East Norway Regional Health Authority and Faculty Division Akershus University Hospital. The authors declare that all researchers involved were free and independent from the funders regarding the research conducted and its contents and results.
The authors declare that the items included in the STROBE statement have been complied with and relevant points have been included directly in the present manuscript or by reference to Grande et al.2
Ethics approval: The Regional Committee for Medical Research Ethics and the Norwegian Social Science Data Services approved the study.
See Editorial Commentary, p 704