Validity of the Severity of Dependence Scale for detecting dependence behaviours in chronic migraine with medication overuse

Aims: In this study, we tested the validity of the Severity of Dependence Scale in detecting dependence behaviours in patients with chronic migraine and medication overuse (CM + MO) using the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) and the Leeds Dependence Questionnaire as gold standard measures. Methods: Four hundred and fifty-four patients with CM + MO filled in the Severity of Dependence Scale and the Leeds Dependence Questionnaire and underwent a psychological evaluation for the diagnosis of substance dependence according to the DSM-IV criteria. Results: Sixty-nine percent of subjects (n = 313) presented substance dependence according to the DSM-IV criteria. These patients scored significantly higher than those without substance dependence in Severity of Dependence Scale total score (Z = −3.29, p = 0.001), and in items 1 (Z = −2.44, p = 0.015), 2 (Z = −2.50, p = 0.012), 4 (Z = −2.05, p = 0.04), and 5 (Z = −3.39, p = 0.001). Severity of Dependence Scale total score (β = 0.13, SE = 0.04, z = 3.49, p < 0.001) was a significant predictor for substance dependence. Receiver Operating Characteristic (ROC) curves showed that Severity of Dependence Scale discriminated patients with or without substance dependence. Conclusion: Severity of Dependence Scale could represent an interesting screening tool for dependency-like behaviors in CM + MO patients.