Cases of acute psychosis which during longitudinal follow-up did not meet criteria for schizophrenic psychosis or affective psychosis are common in clinical practice; however, those cases can be classified into diagnostic categories that are not sufficiently representative of their nosological individuality. This intermediate group of psychosis: characterized by acute onset, usually brief course, polymorphic symptomatology and recovery without defect, has been conceived in different psychiatric schools through different concepts: in this sense, the construct of Cycloid Psychoses, original from German psychiatry, has demonstrated validity and is embedded in a heuristically profitable diagnostic system (the Wernicke-Kleist-Leonhard classification). Apropos of two representative cases, we review here the relevant literature and highlight the need to consider this diagnostic possibility - not fully considered in the present diagnostic systems yet- in order to avoid prolonged antipsychotic treatments based on unnecessarily ominous nosological hypothesis.