Yeah, like bob said, it's probably due to high(er) amounts of kavain which can result in higher norepinephrine levels (it indirectly acts as a weak NE reuptake inhibitor) which will definitely have that effect. Also, and this is probably less likely, but Desmethoxyyangonin can is a weak and reversible MAOI-B inhibitor so it will increase levels of dopamine and phenylethylamine which obviously have that effect, although I would say it's most likely due to the Kavain NAT action.