Delusional phenomenology--dimensions of change.

Although the application of cognitive techniques to both the measurement and modification of delusional beliefs has recently been developed in more theoretical detail (e.g. Chadwick & Lowe, 1994, Behaviour Research and Therapy, 32, 355-367) there has not been an effort to examine the variability of delusional phenomenology across time. In the present study we report on the treatment of 6 individuals who fulfilled DSM-III-R (American Psychiatric Association, 1987) criteria for Delusional Disorder and who received cognitive therapy targeted specifically on the single symptom of their delusional belief(s). Single-case time-series methodology was used to examine the associations between different aspects of delusional phenomenology through baseline and intervention study phases. Belief maintenance factors were found to be significantly associated with conviction in all 3 individuals who responded to the intervention. Negative behaviours, affect associated with the belief, preparedness to talk to others about the belief and insight were associated with conviction in some individuals but not others. Preoccupation and acting on the belief were aspects of delusional phenomenology that were found to systematically vary independent of belief conviction. The results support a multidimensional view of delusional phenomenology and the process of change during cognitive intervention.