What is schizophrenic in acute and transient psychotic disorder?

Acute and transient psychotic disorder (ATPD) is supposed to differ from schizophrenia, but little research has been done on the subject. In a prospective longitudinal case control study we compared all inpatients with ATPD (ICD-10 F23) treated at Halle University Hospital during a 5-year period with matched controls with "positive" schizophrenia (PS) and with mentally healthy controls. Followup investigations were performed at a mean of 2.2 years after the index episode or 8.2 years after the first episode. Female preponderance in ATPD was marked (78.6%). ATPD and PS patients were similar to each other (but different from healthy controls) in the prevalence of a "broken home" situation and a family history for mental disorders. Compared with PS patients, ATPD patients showed better premorbid social adaptation, and they more often displayed rapidly changing symptoms in the index episode and a negative life event preceding the episode. Despite comparable relapse rates, at followup ATPD patients showed better social adaptation, less psychological impairment, and better global functioning than PS patients. These data support the delineation of ATPD from schizophrenia.