Panic reactions—i. e., maximal fear states which result from prolonged tension and insecurity, occur in certain constitutional make-ups as a reaction to specific life situations. Panics develop as a climax of a tension depression, or they may form an important and prolonged phase in depressions with uneasiness and anxiety. This latter group has been described as an anxiety psychosis (Wernicke). I distinguish these two groups of leading panics from mere incidental panics, which may occur in any psychosis or psychoneurosis.A thorough discussion of the literature shows the development of the concept of panic in psychiatry and reviews especially the attitude to the impure affects of anxiety, fear, panic and fright. Impure affects have to be studied from a genetic-dynamic point of view. This leads to the recognition of their far-reaching influence. Much of what has been diagnosed schizophrenic admixtures can be explained by impure affects.The term tension depression which is used in this paper does not coin a new disease entity, but describes reactions of an attack type in which tension and its symptoms are the outstanding complaint and in which the depressive affect seems to play a subordinate rOle. Because of their course and their close relation to depressions, tension depressions are considered to belong to the affective reaction type.From a formal point of view we distinguish between paranoid and disorganizing panics. Their relation to paranoic and schizophrenic reactions is fully discussed.