1Various attempts at explaining psycho-analytically the formation of paranoid ideas are reviewed. With one exception they do not seem to explain satisfactorily the distinctive characteristic of paranoid ideas, viz. their inaccessibility to influence. The exception is provided by Freud's late hypothesis that the adherence to a delusional idea is due to its intrinsic, though distorted, content of truth.

2There are three possible solutions to the conflicts between individual instinctual equipment and reality: an equilibrium can be established by changing reality (alloplasticism) or by changing the instinct (autoplasticism) or by changing neither but denying one or the other. These methods lead, wherever successful, to various types of normality, i.e. a dominating type, a submissive type, and a type with a rich phantasy life. When unsuccessful, they provide the breeding ground for psychopathy, psychoneurosis, and paranoia respectively.