This study examined the strength of delusional beliefs during the modification of delusional verbalizations of a 5 1 year-old chronically mentally ill inpatient. The changing-criterion design was used to document the effectiveness of a behavioral treatment package to alter the rate of delusional responses to personal background questions. The results revealed a stepwise decline in the frequency of delusional responses. Generalization effects to novel interviewers were obtained. No changes were obtained on the subject's ratings of delusional beliefs, with the subject assigning ratings of absolute conviction to his beliefs throughout the duration of the study.

This study evaluated the intensity of delusional beliefs during the modification of delusional verbalizations with three chronically mentally ill inpatients. The multiple-baseline across responses design was used to evaluate the efficacy of a behavioral treatment package to modify delusional verbalizations. Results revealed that changes were obtained in delusional verbalizations to personal questions without corresponding changes in the subjects' delusional beliefs. Changes in delusional verbalizations were well-maintained for two subjects during a 6-month follow-up period. Mixed results were obtained for generalization probe interviews.