The Severity of Dependence Scale detects people with medication overuse: the Akershus study of chronic headache

To evaluate the Severity of Dependence Scale (SDS) in people with primary chronic headache and analyse the pattern of medication overuse.

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.

Akershus University Hospital, Oslo, Norway.

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.

SDS score in those with and without medication overuse.

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).

The SDS questionnaire detects medication overuse and dependency-like behaviour in persons with primary chronic headache.