Thy certainly did. They just had very poor theories about humors and xi and bile.

Did Aristotle know about the relationship of seratonin and the feeling of happiness? I believe not. Therefore, he could not have advised about hapiness and seratonin. If you claim Aristotle knew about Seratonin, maybe you can give a reference.

They probably knew about feedback loops, though, given the creation of waterclocks. Applying those principles to psychology is a short leap, yes ?

I don’t understand what you mean and I will not continue the discussion, instead I’m reading this article in the Stanford Encyclopedia of Philosophy, a great article about Aristotle’s ideas on the topic. https://plato.stanford.edu/entries/aristotle-ethics/