This is the first book in English devoted to thepsychology of delusions. The concept is critically discussed and the literature comprehensively reviewed. A new model of delusions is presented, derived from experimental studies, emphasizing the variety of factors which may play a role in their development including biased reasoning, abnormal experience and disturbed emotions. New possibilities for psychological therapy are also discussed.

1. Concept of Delusion

Introduction

Definitions

Irrationality

Occurrence of delusions in 'schizophrenia' and other disorders

Types of delusion

On distinguishing delusions from obsessions and hallucinations

Accessing (or assessing) delusions

Delusions as beliefs

Delusions and behaviour

Conclusions

2. Reasoning, Rationality, and Delusions

Introduction

Theories of reasoning and rationality

Experimental studies of reasoning in normals

Conclusions

3. Studies of Reasoning in People with Psychosis

Introduction

Reasoning in people with delusions

Reasoning in schizophrenic subjects

Conclusions

4. The Assessment of Delusion

Introduction

Instruments for assessing delusions

Personal questionnaire

Techniques for assessing delusions

Methods

Results

Discussion

Measures to assess responsivity of delusions to evidence

Conclusions

5. Characteristics of Delusional Experience

Introduction

Method

Results

Discussion

Conclusions

6. Theories of the Formation and Maintenance of Delusions

Introduction

Early theories of delusion formation

Current theories

A Bayesian model fo the formation and maintenance of delusions

Other considerations

Conclusions

7. Reasoning in People with Delusions

Introduction

A pilot study

Reasoning in deluded patients

Conclusions

8. Reasoning about Delusions

Introduction

The reasoning about delusions

Structured interview study: method

Results

Discussion

Conclusions

9. Towards a Model of Delusion Formation

Introduction

Concepts and definitions of delusions

Towards a model of delusion formation

A case example

Delusions and schizophrenia research

Concluding remarks

Appendix 1: Reasoning about delusions: a structured interview

Appendix 2: Notes on reasoning about delusions: a structured interview

Appendix 3: List of belief statements

References