psychohistory is from "the foundation" and last time I checked is fictional. If someone has a new theory of sociology which they've named after the field in the book, you might link it and introduce it as if it's a new unknown field, rather than some established thing that everyone should know about and agree with.
If it were truly rigorously proved and were able to make quantitative predictions, it would have some pretty significant implications for policy, finance, politics, etc..
However if the creator was brash enough to name their pet theory after the theory in the book, I'm skeptical that they were careful enough to get it right.