Löfgren proposes a revised model of the psychic apparatus. The ego is seen as an assembly of structures with potentials of various sizes which insulate pools of energy from free intercommunication and the id. Small waves of energy moving across the potentials and changing their levels is secondary process thinking with no experience affect. Drainage of energy into the id and invasion of the ego by the primary process breaks down these potentials and results in anxiety. Circumscribed drainage and localized appearance of the primary process causes pleasurable affect. Localized drainage from the ego into the superego produces unpleasurable affect; generalized drainage causes depression.