Delusions that "CIA did it" are of course common, but it's also true that it's extremely common for people to say you're delusional or paranoid when you describe things the CIA has admitted to in public.

Take a look at the findings of the Church Committee, or at Operation Condor, Operation Mockingbird, the coup in Iran (admittedly a CIA operation), the CIA fomented strikes and civic unrest in Chile after Allende's election, Gladio, the "Jakarta Method", etc.