Schizophrenia Spectrum Disorders: An Empirical Benchmark Study of Real-world Diagnostic Accuracy and Reliability Among Leading International Psychiatrists

Background and hypothesis: Assigning a psychiatric diagnosis in real-world situations is often difficult, given that the clinical presentation does not usually conform to the list of condensed, simplified behavioral descriptors of mainstream operational taxonomies (MOT) (eg, ICD-11 and DSM-5). The goal of this study was to benchmark diagnostic accuracy and reliability on a central and severe spectrum of psychopathology (ie, the schizophrenia spectrum disorders [SSDs]), adopting a pragmatic approach as close as possible to real-world clinical settings. Study Design: We examined the diagnostic performance of 30 international psychiatrists experts in SSD. The clinicians were asked to make their clinical best diagnostic estimate for two written clinical vignettes excerpted from real-world SSD cases. Study Results: In the first vignette, 22 out of the 30 clinicians (73.5%) indicated a SSD as their main diagnostic hypothesis. In the second vignette, 12 clinicians (40%) chose SSD as their main diagnostic hypothesis. Only 10 of the 30 clinicians (33%) correctly identified both vignettes as cases of SSD. The level of interrater diagnostic agreement (Fleiss' Kappa) was low but statistically significant (K_Fleiss >= 0.08, P = .01). Conclusions: The results suggest that, even in a sample of influential international psychiatrists, the diagnostic accuracy and reliability on SSD presentations is poor and substantially inferior to those obtained in reliability studies using structured or semi-structured interviews. The widespread adoption of MOT systems in the last decades may have inadvertently eroded the ability of clinicians to detect a typical pattern of psychiatric illnesses.