Implications for neurobiological research of cognitive models of psychosis: a theoretical paper

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 subclihical 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 x environment x 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.