Dr. Johnson collected some of the best words ever.

FA’NCYSICK. adj. [fancy and sick.] One whose imagination
is unsound; one whose distemper is in his own mind.

‘Tis not necessity, but opinion, that makes men miserable;
and when we come to be fancysick, there’s no cure for
it. L’Estrange.

This one may need to be resurrected. Just think of the many, many uses. Likewise fancysickness, N. “to be afflicted with an unsound imagination and distempered mind”, e.g., “Perplexed with Narrow Passages sure does reveal a lot about its author’s fancysickness.”