a1 Department of Psychology, Institute of Psychiatry, King's College London, London, UK
a2 Department of Mental Health Sciences, Royal Free and University College London Medical School, London, UK
a3 School of Medicine, Health Policy and Practice, University of East Anglia, Norfolk, UK
Background Cognitive models of the positive symptoms of psychosis specify the cognitive, social and emotional processes hypothesized to contribute to their occurrence and persistence, and propose that vulnerable individuals make characteristic appraisals that result in specific positive symptoms.
Method We describe cognitive models of positive psychotic symptoms and use this as the basis of discussing recent relevant empirical investigations and reviews that integrate cognitive approaches into neurobiological frameworks.
Results Evidence increasingly supports a number of the hypotheses proposed by cognitive models. These are that: psychosis is on a continuum; specific cognitive processes are risk factors for the transition from subclinical experiences to clinical disorder; social adversity and trauma are associated with psychosis and with negative emotional processes; and these emotional processes contribute to the occurrence and persistence of psychotic symptoms. There is also evidence that reasoning biases contribute to the occurrence of delusions.
Conclusions The benefits of incorporating cognitive processes into neurobiological research include more sophisticated, bidirectional and interactive causal models, the amplification of phenotypes in neurobiological investigations by including emotional processes, and the adoption of more specific clinical phenotypes. For example, there is potential value in studying gene×environment×cognition/emotion interactions. Cognitive models and their derived phenotypes constitute the missing link in the chain between genetic or acquired biological vulnerability, the social environment and the expression of individual positive symptoms.
(Online publication March 05 2007)
c1 Address for correspondence: Professor Philippa Garety, Department of Psychology PO77, Henry Wellcome Building, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK. (Email: firstname.lastname@example.org)