Diagnostic significance of Schneider's first-rank symptoms in schizophrenia. Comparative study between schizophrenic and non-schizophrenic psychotic disorders

Abstract

Background: Despite the lack of consistent empirical support, modern diagnostic criteria of schizophrenia give particular emphasis to Schneider's first-rank symptoms (FRSs).

Aims: To examine the diagnostic significance of FRSs for schizophrenia by trying to overcome the limitations of previous studies.

Methods: This study examined the diagnostic accuracy of FRSs for schizophrenia in 660 in-patients with the full spectrum of functional psychotic disorders. Schizophrenia was diagnosed according to three criteria: DSM-III-R broad, DSM-III-R narrow and Feighner, the latter being considered as the gold standard because it does not give particular emphasis of FRSs.

Results: FRSs were highly prevalent in both schizophrenia and non-schizophrenic psychoses. The likelihood ratios (and 95% CI) of one or more FRSs for Feighner, DSM-III-R narrow and DSM-III-R broad schizophrenia were 1.06 (0.94-1.20), 1.23 (1.09-1.39) and 1.73 (1.44-2.08), respectively. These data indicate that FRSs do not significantly increase the likelihood of having schizophrenia.

Conclusions: FRSs are not useful in differentiating schizophrenia from other psychotic disorders. Diagnostic systems for schizophrenia that are heavily based on these symptoms may arise from a tautological definition of the disorder.