Background:
Delusions are first-rank symptoms of schizophrenia. Of all delusional themes, delusions of persecution are the most commonly observed clinically and the most vigorously researched empirically. Bentall et al. claim that persecutory delusions are constructed defensively, for the maintenance of self-esteem. A central prediction of their model is that paranoid individuals will show normal or high self-esteem on overt measures, whereas covert measures will show hidden feelings of low self-esteem.
Methods:
The present study used a new methodology that has been widely used in investigations of implicit attitudes, the Implicit Association Test (IAT), to assess covert self-esteem and to test the above prediction. Overt self-esteem was assessed using the Rosenberg Self-Esteem Scale and an adjective self-relevance ratings measure. These measures were administered to 10 patients with acute persecutory delusions, 10 patients with persecutory delusions in remission and 19 matched healthy control participants.
Results:
Patients with acute persecutory delusions were found to have lower covert self-esteem (as assessed using the IAT) than healthy controls and patients with remitted persecutory delusions. On the two measures of overt self-esteem, however, the persecu-tory deluded group did not differ significantly from the other groups once the effects of comorbid depression had been taken into account.
Conclusions:
The results of the present study are consistent with a model of persecutory delusions as serving a defensive function. As such, they are consistent with a psychotherapeutic approach to what are perhaps the most frequently observed symptoms of schizophrenia.
