Acute and transient psychotic disorder: a 1-year follow-up study.

A study sample consisting of 51 patients suffering from acute and transient psychotic disorder (ATPD) (ICD-10) on initial examination was evaluated at 1-year follow-up. The findings show a diagnostic change in half of the patients (48%), most often to schizophrenia (15%) and affective disorder (28%). From index admission to follow-up, patients with an unchanged diagnosis of ATPD manage fairly well with regard to psychosocial functioning, and no deteriorating development is observed. In the majority of cases no personality disorder (PD) (ICD-10, 54%; DSM-IV, 71%) is apparent, and the ATPD is not related to any specific PD. With regard to diagnostic stability, no significant demographic, social or clinical predictors were found. The findings highlight the need for validation of the concept of ATPD, and point to the fact that brief psychotic episodes with an acute onset may be an early manifestation of severe mental disorder (schizophrenia and affective disorder).