A 22-year-old female presents with delusions of grandeur, disorganized speech, and significant functional impairment for the past 4 months. She denies any history of depressive or manic episodes. Her symptoms began abruptly after a stressful life event. Based on the duration of her symptoms, what is the most appropriate diagnosis?

Explanation

The duration of symptoms is crucial for differentiating psychotic disorders. Brief psychotic disorder involves symptoms lasting less than 1 month. Schizophreniform disorder is diagnosed when symptoms of schizophrenia (delusions, hallucinations, disorganized speech, grossly disorganized or catatonic behavior, negative symptoms) are present for at least 1 month but less than 6 months. Schizophrenia requires symptoms to be present for at least 6 months, including at least 1 month of active-phase symptoms. Schizoaffective disorder involves a concurrent mood episode (major depressive or manic) with psychotic symptoms, where psychotic symptoms are also present for at least 2 weeks in the absence of a major mood episode during the illness's lifetime. Given the 4-month duration of symptoms, schizophreniform disorder is the most appropriate diagnosis.