The term, acute and transient psychosis, is comprehended as a heterogeneous group of disorders, which share, as a common feature, the abrupt and brief deployment of typical psychotic behaviour, either polymorph, delusional, or schizophreniform. This diversity of symptoms may also be present in other psychotic disorders, for which, some authors question its reliability.

To analyse the clinical manifestations present in acute and transient psychotic disorders (ATPD), and determine the differences between its different subcategories.

Retrospective chart review study of adult patients admitted in our psychiatric unit between 2011 and 2015, with a mean diagnosis of ATPD at hospital discharge. Diagnostic criteria was according to the International Classification of Diseases (ICD-10). Symptoms were divided under operative procedures, as set out in psychopatologic descriptions. For methodological reasons, statistical analysis was conducted between polymorphic features group (PM) and nonpolymorphic group (NPM). Chi-squared test and Fisher's exact test (as appropriate) were performed, using MedCalc software.

Thirty-nine patients met the inclusion criteria. Acute polymorphic psychotic disorder with and without symptoms of schizophrenia (39%), acute schizophrenia-like psychotic disorder (20%), acute predominantly delusional psychotic disorder (23%), other and NOS (18%). There were statistically significant differences between PM and NPM groups in emotional turmoil (>PM, P = 0.0006), grossly disorganized or abnormal motor behaviour (>PM, P = 0.0038), and type of onset (sudden >PM, P = 0.0145).

Currently, the same concept encompasses two categories (PM and NPM) to be differentiated. The ATPD construct is under review, due its long-term instability.

The authors have not supplied their declaration of competing interest.