The Diagnostic Significance of Overinclusive Thinking in an Unselected Psychiatric Population

Payne and Friedlander's battery of three tests of overinclusive thinking was administered to 100 consecutive mental hospital admissions between the ages of 16 and 55 who were free of medication, who were not brain damaged, and who had a Mill Hill Vocabulary I.Q. of 80 or more. In this population, the intercorrelations among the tests were very low, only one attaining statistical significance. When the patients were grouped according to their final psychiatric diagnosis, the groups did not differ significantly on the overinclusion measures. The overinclusion measures similarly were mainly non-significantly correlated with psychiatric rating of five delusional symptoms. The study provided no evidence that this test battery can be used clinically for diagnostic or descriptive purposes with such a psychiatric population.