Distinguishing between first-admission schizophreniform disorder and schizophrenia

Background: The validity of schizophreniform disorder remains controversial. Past research suggests that cases of schizophreniform disorder may be: (1) atypical cases of affective disorders, (2) cases of schizophrenia in early course, or (3) a heterogeneous group of disorders including a subgroup with benign course and outcome which maintains this diagnosis in the long term. Method: We tested the validity of the schizophreniform disorder diagnosis by comparing the socio-demographic and baseline clinical characteristics, 24-month course and outcome, and 6- and 24-month research diagnoses of 34 cases initially diagnosed with schizophreniform disorder, and 128 cases with schizophrenia, drawn from a cohort of 628 first-admission patients in the Suffolk County Mental Health Project. Results: Compared to patients with schizophrenia, those with schizophreniform disorder were more likely to remit fully by 6 months and retain this status by 24 months. Only about half of the patients with schizophreniform disorder were re-diagnosed with schizophrenia or schizoaffective disorder at 24-month follow-up, 13% were re-diagnosed with affective disorders and 19% retained the diagnosis of schizophreniform disorder. In contrast, 92% of cases with a baseline diagnosis of schizophrenia retained this diagnosis at 24-month follow-up. The findings were similar in comparisons with schizophrenia patients having onset of symptoms within 6 months of hospitalization. Conclusions: Schizophreniform disorder is a heterogeneous category, which includes a small group with benign psychotic disorders who maintain this diagnosis over at least 24 months. Better delineation of this subgroup has important treatment implications. (C) 2002 Elsevier Science B.V. All rights reserved.