in DSM–IV–TR and DSM–5, a disturbance involving the sudden onset of at least one psychotic symptom (e.g., incoherence, delusions, hallucinations, or grossly disorganized or catatonic behavior). 

The condition is often accompanied by emotional turmoil and lasts from 1 day to 1 month, with complete remission of all symptoms and a full return to previous levels of functioning. It may develop following a period of extreme stress, such as the loss of a loved one. Formerly called brief reactive psychosis.