VALPROATE TREATMENT OF PANIC DISORDER AND LACTATE-INDUCED PANIC ATTACKS

Several lines of evidence suggest that the anticonvulsant drug valproa te may have antipanic properties: (1) It enhances gamma-aminobutyric a cid activity in the brain; (2) it has anxiolytic effects in animal mod els of anxiety; and (3) it has been reported to be effective in panic disorder in several preliminary studies; however, valproate has not be en studied in the prevention of lactate-induced panic attacks. Sixteen patients with panic disorder underwent a lactate infusion followed by a 28-day treatment period with valproate and subsequent rechallenge w ith lactate. Response was measured by change in panic attack frequency and Hamilton Anxiety Scale (HAS) scores and by the ability of valproa te to block lactate-induced panic on rechallenge. Of the 14 patients c ompleting the 28-day trial, 10 (71%) experienced a greater than 50% re duction in the weekly frequency of panic attacks. Six (43%) had comple te remission. HAS scores dropped significantly from a baseline mean of 30.8 +/- 9.4 (SD) to 12.6 +/- 7 after 4 weeks of treatment. Valproate blocked reinduction of panic symptoms on lactate rechallenge in 10 (8 3%) of 12 patients who had initially experienced panic symptoms on ini tial infusion. The significant reduction in spontaneous panic attacks and the blockade of lactate-induced panic symptoms by valproate suppor t earlier studies suggesting that the drug may be an effective treatme nt for panic disorder.