Back when I was floridly delusional (the late 60’s and early 70’s), the delusions would often be political. Now I see a lot of delusions from “you youngsters” about spiritual things – spirits and devils/demons and gods, and also about personal relationships.
Maybe these are signs of the times. I see in “A Beautiful Mind” the delusions were portrayed as being about the cold war. Before that maybe the delusions were about World War II. And before that about poverty if you were SZ during the depression.