Acute polymorphic psychotic disorder: diagnostic stability over 3 years

OBJECTIVE: Acute polymorphic psychotic disorder without symptoms of schizophrenia (APPD) in ICD-10 is unique in many characteristics. This study aimed at investigating the diagnostic stability of APPD over 3 years. METHOD: Forty-five patients with first episode APPD were followed up and assessed at regular intervals over a period of 3 years. RESULTS: Thirty-two patients were females. Average age of the sample was 26.9 years. Thirty-three cases retained their index diagnosis of APPD, while 12 cases required diagnostic revision: 10 to bipolar affective disorder and the rest to unspecified non-organic psychosis. Shorter duration of illness (<1 month) and abrupt onset (<48 h) predicted a stable diagnosis of APPD. CONCLUSION: APPD is a relatively stable diagnosis and argues for a distinct diagnostic entity.