FOULDS HIERARCHY - VALIDATION OF PREDICTIONS IN PSYCHIATRIC AND DERMATOLOGICAL PATIENTS

Foulds' inclusive non-reflexive law of symptom formation has been hith erto confirmed only on psychiatric or non-clinical persons. Given that respectively a yes-bias and a high frequency of non-classified patien ts may have inflated the rate of confirming protocols in these groups, a validation study was conducted with the Delusions-Symptoms-States I nventory (DSSI) on 188 psychiatric and 295 dermatological patients. Al though non-classified patients were not included in the study (thus lo wering the number of conforming patterns), both samples showed percent ages of patterns conforming to Foulds' law which were above 85 per cen t. No significant intergroup difference was found. The rate of conform ing patterns in both groups was lower for members of the two psychotic classes (61-77 per cent). Foulds further hypothesized that the number of pathological sets within a given class grows if there is allocatio n into a superordinate class. This assumption was confirmed in both gr oups and for most of the inter-class comparisons. Suggestions were adv anced to clarify the issue of the time span to be covered by Foulds' p yramid, to refine the instructions and the response format of the DSSI , and to include into the pyramid further relevant disturbances.