Demonism (synonymous with daemonomania = possession) denotes a peculiar state of mind characterized by the fact that certain psychic contents, the so-called complexes, take over the control of the total personality in place of the ego
Jung provides his formal clinical definition of demonism as complex-possession, tying the archaic religious category directly to analytical psychology’s concept of autonomous complexes displacing ego-governance.
, Collected Works Volume 18: The Symbolic Life, 1976thesis