No, conspiracy is governed by statute in federal courts and most state courts.
Conspiracy is “an agreement between two or more persons to engage jointly in an unlawful or criminal act, or an act that is innocent in itself but becomes unlawful when done by the combination of actors.” https://legal-dictionary.thefreedictionary.com/conspiracy
The term “conspiratorial delusions” seems to be something you made up.
You and I are like two audience members debating whether the card trick at a magic show is real or not.