S-17-01

Experimental psychology of delusions

T. Kircher. Klinik für Psychiatric u. Psychotherapie, RWTH, Aachen, Germany

Objective: The present study investigated whether a failure of self-monitoring contributes to core syndromes of schizophrenia.

Methods: Three groups of patients with a DSM IV diagnosis of schizophrenia (n = 27; with either prominent paranoid hallucinatory or disorganization syndrome, or without these symptoms) and a matched healthy control group (n = 23) were drawing circles on a writing pad connected to a PC monitor. Subjects were instructed to continuously monitor the relationship between their hand movements and their visual consequences. They were asked to detect gain changes in the mapping. Self-monitoring ability and the ability to automatically correct movements were assessed.

Results: Patients with either paranoid-hallucinatory syndrome or formal thought disorder were selectively impaired in their ability to detect a mismatch between a self-generated movement and its consequences, but not impaired in their ability to automatically compensate for the gain change.

Conclusion: These results support the claim that a failure of self-monitoring may underlie the core symptoms of schizophrenia.

S-17-02

The effects of angry and happy expressions on recognition memory for unfamiliar faces in delusion-prone subjects

F. Laroi, A. D'Argembeau, M. Van Der Linden, C. Bertoni. University of Liege Cognitive Psychopathology Unit, Liege, Belgium

Objective: Numerous studies suggest a cognitive bias for threat-related material in delusional ideation. However, few studies have examined this bias using a memory task. We investigated the influence of delusion-proneness on identity and expression memory for angry and happy faces.

Methods: Participants high and low in delusion-proneness were presented with happy and angry faces and were later asked to recognize the same faces displaying a neutral expression. They also had to remember what the initial expressions of the faces had been. Remember/know/guess judgments were asked for both identity and expression memory.

Results: Results showed that delusion-prone subjects better recognized the identity of angry faces compared to non-delusional subjects. Also, this difference between the two groups was mainly due to a greater number of Remember responses in delusion-prone subjects.

Conclusion: These findings extend previous studies by showing that delusions are associated with a memory bias for threat-related stimuli.

S-17-03

Knowledge corruption in paranoid schizophrenia

S. Moritz. UKE Hamburg, Hamburg, Germany

Objective: A number of recent memory studies have demonstrated that schizophrenia patients display knowledge corruption, that is, they hold false information with strong conviction. This metamemory abnormality is thought to stem from poor memory accuracy (increased errors) in conjunction with a decreased ability to discriminate correct and incorrect judgments in terms of confidence (i.e., enhanced confidence in errors and decreased confidence in correct responses in comparison to controls). Knowledge corruption is theorized as a potential risk factor for the emergence of fixed, false beliefs (i.e. delusions).

Methods: Two studies will be presented. Thirty-one schizophrenic patients were compared to 62 healthy and 48 psychiatric controls (OCD and PTSD patients) on a source-memory task that assesses both memory accuracy and response confidence. In a second study, 41 first-episode patients were compared to 21 healthy controls on a variant of the same task.

Results: In the first study, schizophrenic patients displayed significantly more knowledge corruption than healthy controls and PTSD as well as OCD patients. In agreement with prior results, schizophrenic patients were over-confident in errors while being at the same time under-confident for correct responses. The second study suggests that a meta-memory deficit can be found in both chronic and first-episode schizophrenic/ schizophreniform patients.

S-17-04

Theoretical and clinical implications of an attribution model of paranoia

P. Kinderman. University of Liverpool, Liverpool, United Kingdom

Objective: Attributional theory has been one of the most influential frameworks in clinical psychology. In particular, individuals with persecutory delusions have been hypothesised to demonstrate a particular attributional style that is suggested to protect them from real or delusional threats to their self-esteem. It has further been proposed that this attributional bias could maintain persecutory delusions and is a possible area of therapeutic intervention. More recent research has explored the relationship between 'jumping to conclusions' (Garety & Freeman, 1999) and causal attributions was investigated in persecutory delusions.

Methods: Individuals with persecutory delusions were compared with matched depressed psychiatric and non-psychiatric comparison groups using a modified inductive reasoning task (John & Dodgson, 1994) on which participants requested information before making attributions for common social events.

Results: This presentation will summarize the research literature on attributional abnormalities in paranoia.

Conclusion: Clinical data on the effectiveness of therapeutic approaches based on such attributional models will be presented.

S-17-05

Testing a cognitive model of persecutory delusions using virtual reality

D. Freeman. Institute of Psychiatry, London, United Kingdom

Objective: The presenter and colleagues have recently detailed a cognitive model of persecutory delusions (Freeman et al, 2002; Freeman & Garety, 2004). Factors outlined in the model were used to predict the occurrence of persecutory ideation in a controlled neutral virtual reality environment.

Methods: The results of 2 studies will be described. In both studies non-clinical individuals, after completing a range of psychological assessments, entered a VR library scene in which there were 5 characters. After spending time in the environment, participants then completed a measure of persecutory ideation about the computer characters.

Results: In both studies a proportion of participants experienced persecutory ideation. Providing evidence of the validity of the experimental method, persecutory ideation was predicted by higher trait paranoia. The psychological variables from the cognitive model that predicted persecutory ideation were anxiety, interpersonal sensitivity, and hallucinatory predisposition. Further, hallucinatory predisposition distinguished the prediction of paranoid thoughts from social anxiety in virtual reality.

Conclusion: Virtual reality provides a new experimental means of investigating paranoia. Key factors from the cognitive model predicted persecutory ideation: non-clinical paranoid thoughts were most closely associated with anxiety and anomalous experiences. Reasoning biases may particularly contribute to the development of clinical phenomena.