Adjunctive zonisamide for treatment refractory anxiety

The aim of the study was to assess the use of a novel anticonvulsant, zonisamide, in patients with treatment refractory anxiety. Pilot and open study of a cohort of patients with anxiety (n = 10), who were deemed partial or non-responders to anxiolytic therapy, and received adjunctive zonisamide in a naturalistic fashion. The primary outcome measures were the Hamilton Anxiety Scale (HAM-A), the Clinical Global Impression of Severity (CGI-S) and the Clinical Global Impression of Improvement (CGI-I). Patients included were markedly ill with a mean number of previous medication trials of 4.9 +/- 1.9, a baseline HAM-A score of 27.9 +/- 3.8, and a baseline CGI-S score of 5.7 +/- 0.5. Patients improved significantly with an end-point HAM-A score of 12.6 +/- 7.4 (p < 0.001), CGI-S score of 3.6 +/- 1.3 (p < 0.002) and CGI-I score of 2.5 +/- 1.3. Zonisamide at a mean +/- SD dose of 160 +/- 70 mg/day for 9.2 +/- 4.5 weeks was generally well tolerated. Adverse events were generally mild, and no patients discontinued zonisamide because of side effects. Six patients (60%) met responder criteria at end-point (CGI-I