THE RELIABILITY OF BIZARRE DELUSIONS

The concept of bizarre delusions figures prominently in the diagnosis of schizophrenia under DSM-III-R criteria. Yet this concept may be difficult to apply in the clinical world. The interrater reliability of distinguishing bizarre versus non-bizarre delusions was estimated by compiling a sample of 40 delusional ideas and asking a group of psychiatrists (ranging from experts in the field to residents) to identify them as bizarre or non-bizarre. The interrater reliability of the 45 respondents was consistently low as measured by kappa statistic (κ < 0.40) within and across groups of raters, and regardless of whether or not a structured definition was applied. Implications for DSM-IV are discussed. © 1991.