Confidence in Errors as a Possible Basis for Delusions in Schizophrenia

In two previous studies, it was observed that schizophrenic patients display increased confidence in memory errors compared with controls. The patient group displayed an increased proportion of errors in their knowledge system, quantified as the percentage of high-confident responses that are errors. The latter phenomenon has been termed knowledge corruption and is put forward as a risk factor for the emergence of delusions. In the present study, knowledge corruption was analyzed separately for different aspects of memory errors. A source-monitoring task was used, for which participants (30 schizophrenic patients with past or current paranoid ideas and 15 healthy controls) were asked to provide associates for each of 20 prime words. Later, participants were required to recognize studied words among distractor words, judge the original source, and provide a confidence rating for the most recent decision. Schizophrenic patients displayed greater confidence in memory errors compared with controls. Knowledge corruption was observed to be significantly greater in schizophrenic patients relative to controls for false-positive and false-negative judgments. It is proposed that reliance on false knowledge represents a candidate mechanism for the emergence of fixed false beliefs (i.e., delusions).

[1]  R. Mass,et al.  Potential for misdiagnosis amongTurkish migrants with psychotic disorders:a clinical controlled study in Germany , 2000, Acta psychiatrica Scandinavica.

[2]  W. Russell.  THE COMPLETE GERMAN LANGUAGE NORMS FOR RESPONSES TO 100 WORDS FROM THE KENT-ROSANOFF WORD ASSOCIATION TEST , 1970 .

[3]  R. Kahn,et al.  Memory impairment in schizophrenia: a meta-analysis. , 1999, The American journal of psychiatry.

[4]  T. Woodward,et al.  Memory confidence and false memories in schizophrenia. , 2002, The Journal of nervous and mental disease.

[5]  P. Garety,et al.  The Formation of Maintenance of Delusions: a Bayesian Analysis , 1986, British Journal of Psychiatry.

[6]  C. Huron,et al.  Impairment of recognition memory with, but not without, conscious recollection in schizophrenia. , 1995, The American journal of psychiatry.

[7]  P. Garety,et al.  Probabilistic Judgements in Deluded and Non-Deluded Subjects , 1988, The Quarterly journal of experimental psychology. A, Human experimental psychology.

[8]  Claude Alain,et al.  Neurophysiological evidence of error-monitoring deficits in patients with schizophrenia. , 2002, Cerebral cortex.

[9]  M. Spitzer,et al.  On defining delusions. , 1990, Comprehensive psychiatry.

[10]  M. Spitzer,et al.  A cognitive neuroscience view of schizophrenic thought disorder. , 1997, Schizophrenia bulletin.

[11]  Murphy Hb.  Cultural aspects of the delusion. , 1967 .

[12]  S. Moritz,et al.  An analysis of the specificity and the syndromal correlates of verbal memory impairments in schizophrenia , 2001, Psychiatry Research.

[13]  C. Walker.  Delusion: What Did Jaspers Really Say? , 1991, British Journal of Psychiatry.

[14]  B. Maker.  Anomalous Experience in Everyday Life: Its Significances for Psychopathology , 1999 .

[15]  P. Garety,et al.  Cognitive approaches to delusions: a critical review of theories and evidence. , 1999, The British journal of clinical psychology.

[16]  Steffen Moritz,et al.  Increased automatic spreading of activation in thought-disordered schizophrenic patients , 2003, Schizophrenia Research.

[17]  P. Liddle,et al.  Signs and Symptoms of Psychotic Illness (SSPI): A rating scale , 2002, British Journal of Psychiatry.

[18]  Jane S. Paulsen,et al.  Neuropsychological deficits in schizophrenics. Relationship to age, chronicity, and dementia. , 1994, Archives of general psychiatry.

[19]  K. Kiehl,et al.  Rostral anterior cingulate cortex dysfunction during error processing in schizophrenia. , 2003, Brain : a journal of neurology.

[20]  J. Danion,et al.  Functional mechanisms underlying impaired recognition memory and conscious awareness in patients with schizophrenia. , 1999, Archives of general psychiatry.

[21]  L. Bellodi,et al.  Memory functioning in obsessive-compulsive disorder. , 1993, Behavioural neurology.

[22]  C Frith,et al.  Brain mechanisms associated with top-down processes in perception. , 1997, Philosophical transactions of the Royal Society of London. Series B, Biological sciences.

[23]  D. Stapel,et al.  How far do we go beyond the information given? The impact of knowledge activation on interpretation and inference. , 2000, Journal of personality and social psychology.

[24]  S. Wessely,et al.  Reasoning in Deluded Schizophrenic and Paranoid Patients: Biases in Performance on a Probabilistic Inference Task , 1991, The Journal of nervous and mental disease.

[25]  K. Kiehl,et al.  Error-related negativity and correct response negativity in schizophrenia , 2002, Clinical Neurophysiology.

[26]  K. McDermott,et al.  Creating false memories: Remembering words not presented in lists. , 1995 .

[27]  T. Woodward,et al.  False memories in schizophrenia. , 2004, Neuropsychology.

[28]  T. Woodward,et al.  Source monitoring and memory confidence in schizophrenia , 2002, Psychological Medicine.

[29]  A P Yonelinas,et al.  Consciousness, control, and confidence: the 3 Cs of recognition memory. , 2001, Journal of experimental psychology. General.

[30]  M. Antony,et al.  Memory and confidence in memory judgements among individuals with obsessive compulsive disorder and non-clinical controls. , 1997, Behaviour research and therapy.

[31]  B. Maher,et al.  Delusional thinking and perceptual disorder. , 1974, Journal of individual psychology.

[32]  H. Murphy.  Cultural aspects of the delusion. , 1967, Studium generale; Zeitschrift fur die Einheit der Wissenschaften im Zusammenhang ihrer Begriffsbildungen und Forschungsmethoden.

[33]  K. McDermott,et al.  Factors that determine false recall: A multiple regression analysis , 2001, Psychonomic bulletin & review.

[34]  J. Ford,et al.  Response-monitoring dysfunction in schizophrenia: an event-related brain potential study. , 2002, Journal of abnormal psychology.

[35]  I. Al-Issa.  Social and cultural aspects of hallucinations. , 1977, Psychological bulletin.