Introduction

Brief and acute psychoses – as differentiated from schizophrenia and affective disorders – have long intrigued psychiatrists. Their nosological allocation has been a matter of debate. The World Health Organization (WHO) tried to solve this problem by creating the ICD-10 category F23: “acute and transient psychotic disorders” (ATPD). The ATPD is defined as a psychotic disorder of acute onset (within two weeks) and of limited duration (not longer than three months). For a diagnosis of ATPD, major affective disorders, organic disorders, and schizophrenia have to be ruled out. The creation of this category represented an attempt not only to define and operationalize such psychotic conditions, but also to integrate some national concepts such as the cycloid psychoses of German psychiatry, the bouffée délirante of French psychiatry, the psychogenic psychosis of Scandinavian psychiatry, the atypical psychosis of Japanese psychiatry and the remitting or good-prognosis schizophrenia of USA psychiatry into one single category (Marneros and Tsuang, 1986; Marneros et al., 2000; Pillmann et al., 2000; 2001; Marneros and Pillmann, 2004). The DSM-IV provides the category of brief psychotic disorder (BPD). A diagnosis of BPD requires the presence of delusions, hallucinations, disorganized speech, or grossly disorganized or catatonic behavior, with a duration of at least one day but less than one month and eventual full return to premorbid functioning.