The Two Faces of First-Rank Symptoms.

Recently, there has been renewed interest in Schneider's first-rank symptoms (FRS) of schizophrenia, thanks in part to a meta-analysis of their diagnostic accuracy, which deserves much credit for its methodological rigor. Conceptualising FRS as a diagnostic test whose performance can be measured in terms of sensitivity and specificity involves some issues that require reflection. First, the full adequacy of sensitivity as a measure of diagnostic accuracy for FRS might be questioned. However, it is conceptually acceptable, though FRS are at a disadvantage as compared with many other psychiatric "diagnostic tests" that should have perfect sensitivity under ideal conditions. Also, from a psychopathological perspective it may well be argued that FRS cannot be conceptualised as a simple, inexpensive diagnostic test suitable for screening purposes; however, the history of the concept reveals some reasons why it may be legitimate to view them this way. While no other relevant study has appeared after the publication of the meta-analysis, data on a further 166 patients from a study that could not be included due to incompletely reported data were located. This brought the total to 4,236 patients from 17 studies on the ability of FRS to differentiate schizophrenia from other psychoses. The resulting summary estimates of sensitivity, specificity and positive and negative likelihood ratios are 60.2%, 75.9%, 2.50, and 0.52, respectively. FRS have a kind of double nature, as they can be legitimately considered as belonging to both a sophisticated framework grounded in phenomenological psychopathology and an eminently pragmatic framework grounded in clinical epidemiology. When FRS are conceptualised as simple clinical indicators that require low levels of inference, the available estimates of their diagnostic accuracy are a fairly valid appraisal of their performance and usefulness, and suggest that FRS have some value in differential diagnosis. However, when FRS are conceptualised as profoundly anomalous experiences that can be properly identified and evaluated only by using a phenomenological approach, these estimates can hardly be seen as a valid evaluation of their diagnostic significance. Phenomenologically informed studies are needed to address this research gap.