Single word with same meaning as phrase: "Power goes to head"

Question

I am looking to replace the [] in the sentence:

The regime is showing signs of [power going to their heads].

Namely, I would like to use a single word, or two at most. A scientific-sounding noun would be great. Or if there is no such noun, I would still like to see what is the closest we can get.

I originally considered "autocracy," but it has only a loose connection with power going to heads.

Answer 1

The regime is showing signs of megalomania

NOUN obsession with the exercise of power.

Answer 2

Complacency: (disapproving) a feeling of calm satisfaction with your own abilities or situation that prevents you from trying harder.
Cambridge English Dictionary

Answer 3

Arrogance (noun)
Arrogant (adjective): unpleasantly proud and behaving as if you are more important than, or know more than, other people
Cambridge English Dictionary