A cognitive approach to measuring and modifying delusions.

The present paper summarizes and integrates with the existing literature the results of three studies we have conducted on the measurement and modification of delusions. The findings of two of these studies have been presented previously; the third is briefly reported here. A total of 12 people with delusions took part. Ten participated in two investigations that used between-subject multiple-baseline designs; the remaining two, each of whom held three distinct delusions, took part in a study using an across-beliefs multiple-baseline design. A variety of dimensions of delusional experience were monitored over baseline periods of at least 4 weeks, and two distinct cognitive interventions were used: a structured verbal challenge and a planned empirical test. Our focus in the present article is on intervention and the process of change as people come to question and sometimes reject their delusions. We also address related issues, including problems of measurement (i.e. demand characteristics, independent validation), the connection between depression and delusions and the prediction of treatment response. We conclude with specific recommendations for cognitive therapy for delusions.