Abstract
Acute psychotic disorders do not yield to any attempts of systematic classification. In the paper a comparison is made between various diagnostic conceptions proposed in cases of such disorders, with particular emphasis on the French nosographic conception of bouffée délirante and on research findings suggesting that it constitutes a separate clinical entity. The paper is illustrated by a case of an acute polymorphic psychotic episode with a schizophrenia-like clinical pattern of 6 days' duration in its essential part, ended with a spontaneous regression of symptoms.