Delusions: A Cognitive Perspective

The understanding of delusions, while historically focused on neuropsychological deficits, can be approached from the same cognitive perspective as that applied to other forms of psychopathology. The cross-sectional analysis of delusional thinking shows several cognitive characteristics: egocentric bias (irrelevant events are construed as self-relevant); externalizing bias (strong internal sensations or symptoms are attributed to external agents); and intentionalizing bias (other people’s behaviors are believed to be based on intentions—usually malevolent—towards the patient). In addition, defective reality testing precludes reevaluation and rejection of erroneous conclusions. Consequently, cognitive distortions such as selective abstraction, overgeneralization, and arbitrary inferences are prevalent. From a developmental perspective, grandiose delusions appear to arise from earlier daydreams of glory, serving as a compensation for feelings of loneliness, inadequacy, and inferiority. The daydreams become increasingly real to the patient until they become overt delusions. Persecutory delusions typically begin as a fear of retaliation or discrimination. Because of attentional bias, these fears receive pseudoconfirmation until they become fully formed beliefs that preempt normal information processing and displace more realistic beliefs.