Generalized Anxiety Disorder: A Predictor for Poor Responsiveness to Botulinum Toxin Type A Therapy for Pediatric Migraine.

[BACKGROUND] To assess the efficacy, safety, and predictors for poor responsiveness of botulinum toxin type A (BoNT-A) for chronic migraine in the adolescent and young adult population.

[METHODS] A retrospective analysis of 56 patients who received BoNT-A for chronic migraine with an age range from 13 to 21 years was performed. Of 56 patients, 34 were enrolled in the study based on the inclusion criterion. Patients who received three dosages of BoNT-A were assessed at nine months from the first injection. Variables including age, body mass index, headache intensity, frequency, character, and side effects were assessed. The patients were divided into two groups based on response to BoNT-A therapy, responders and nonresponders.

[RESULTS] Overall among the 34 patients enrolled in the study, the average headache frequency decreased from 18.6 of 28 to 9.9 of 28 days, P value, <0.001 from baseline. There was significant decrease in the average headache intensity, 8.1 to 4.3. Of 34 patients, 25 (73%) patients responded to treatment with decrease in headache frequency by ≥ 50% from the baseline. Among the nonresponder patients, a significant number of patients (six of nine, 67%) had generalized anxiety disorder with Generalized Anxiety Disorder-7 score greater than 15 versus the responder group (six of 25, 24%, P value 0.040).

[CONCLUSIONS] BoNT-A remains a safe and effective therapy for adolescent and young adult patients with chronic migraines at nine months of follow-up. Generalized anxiety disorder with Generalized Anxiety Disorder-7 score greater than 15 can be a major predictor of poor response to this therapy.