Persecutory delusions and the determination of self-relevance : an fMRI investigation N. J. BLACKWOOD, 1 R. P. BENTALL, D. H. FFYTCHE, A. SIMMONS, R. M. MURRAY AND R. J. HOWARD From the Department of Psychological Medicine, Institute of Psychiatry, London ; and Department of Clinical Psychology, University of Manchester ABSTRACT Background. People with persecutory delusions regard ambiguous data in the social domain as self- relevant and selectively attend to threatening information. This study aimed to characterize these social cognitive biases in functional neuroanatomical terms. Method. Eight schizophrenic patients with active persecutory delusions and eight matched normal controls underwent functional magnetic resonance imaging while determining the self-relevance of ambiguous self-relevant or unambiguous other-relevant neutral and threatening statements. Results. In determining self-relevance, the deluded subjects showed a marked absence of rostral– ventral anterior cingulate activation together with increased posterior cingulate gyrus activation in comparison to the normal subjects. The influence of threat on self-relevance determination did not yield statistically significant differences between deluded and normal subjects. Conclusions. Abnormalities of cingulate gyrus activation while determining self-relevance suggest impaired self-reflection in the persecutory deluded state. This may contribute to persecutory belief formation and maintenance. INTRODUCTION Persecutory delusions (in which the patient’s self is the focus of the malign intentions of others) may arise through a disturbance of the psycho- logical processes mediating the formation and maintenance of normal social beliefs. Such pro- cesses include : (1) selection of social data in the environment relevant to oneself ; and (2) infer- ential processing using these data to determine the intentions of others towards oneself in order to guide behaviour. Biases and deficits in both of these sets of processes have been demon- strated in subjects with persecutory delusions (Blackwood et al. 2001). When they are deluded, patients report that ambiguous social data (for example, material from overheard conver- sations) are suffused with potential meaning for the self (Cutting, 1997). In addition, deluded sub- jects selectively attend to threat-related stimuli (Bentall & Kaney, 1989). This attentional bias resolves with clinical recovery. We aimed to characterize these two aspects of attentional bias in the deluded state (differential processing of self-relevance and of threat-to-self) in func- tional neuroanatomical terms. METHOD Eight right-handed male in-patients with ICD-10 paranoid schizophrenia, a mean age of 38 years (S.D.=17, range 20–64) and a mean pre-morbid verbal IQ of 106 (S.D.=8, range 99–120) were studied. The patients were in acute relapse, demonstrating persecutory delusions of at least moderate intensity, scoring o3 on the persecutory delusions subscale of the Scale for the Assessment of Positive Symptoms (Andreasen, 1984 a). Current symptomatology 1 Address for correspondence : Dr Nigel Blackwood, PO Box 70, Department of Psychological Medicine, Institute of Psychiatry, De Crespigny Park, London SE5 8AF. (Email : n.blackwood@iop.kcl.ac.uk) Psychological Medicine, 2004, 34, 591–596. f 2004 Cambridge University Press DOI : 10.1017/S0033291703008997 Printed in the United Kingdom 591