What you really should wonder is ... what do PS inhabitants know about such a thing as hormones or nerves?
My answer, nada, nothing, zip, zilch, zero .. and so on.
Science is rudimentary in PS and even if they had any theories the chance that they'd be on the spot or even have the same names for it are very very small.
If your underlying question is that Krans can get moodswings, it's probably safe to assume that they can.
