yes. i forgot about kava kava. i seem to remember it having a weird affect on someone once.
kava kava-'induces physical and mental relaxation... can cause drowsiness... acts as a diuretic...'- Prescription for Nutritional Healing
one theory about anxiety attacks is that the anticipated fear of having the attack in a given situation triggers the future attacks. visualization and deep breathing exercises help.
herbal stuff will only help over the long term and if you suffer from ongoing anxiety. they take about 6 months...