Validity of self-reported assessment of Severity of Dependence Scale in Medication-Overuse Headache

The interview-based Severity of Dependence Scale (SDS) predicts the outcome of withdrawal therapy in Medication-Overuse Headache (MOH). We aimed to compare the interview-based SDS with a self-administrated written version. Fifty-three MOH patients, 19 chronic headache patients without medication overuse and 25 population controls were recruited from a previous randomized controlled trial. The SDS was scored in a telephone interview by headache experts, further, the participants filled in the SDS as a part of a self-administered questionnaire. The SDS assesses scores dependence through five questions, each scored from 0 to 3. A score of ≥5 is associated with MOH. Mean SDS scores were 2.8 (SD 3.0) vs. 3.1 (SD 2.9), p = 0.12, for the interview vs. the self-reported questionnaire, with a correlation 0.78. There was a non-significant bias of 0.32 (95% limits of agreement of -3.6; 4.2) between the two methods in the Bland-Altman analysis. A self-reported SDS questionnaire can be used, and may yield valuable information as a screening tool prior to headache consultations or studies. The possibilities of designing web-based self-treatment tools based on SDS self-assessment and brief intervention may be a future approach for a large group of patients.