Bridging perspectives - A review and synthesis of 53 theoretical models of delusions

The degree to which numerous existing models of delusion formation disagree or propose common mechanisms remains unclear. To achieve a comprehensive understanding of delusion aetiology, we summarised 53 theoretical models of delusions extracted from a systematic literature search. We identified central aspects and unique or overarching features of five core perspectives: cognitive (n = 22), associative learning (n = 4), social (n = 6), neurobiological (n = 6), and Bayesian inference (n = 15). These perspectives differ in foci and mechanistic explanations. Whereas some postulate delusions to result from associative and operant learning, others assume a disbalance in the integration of prior beliefs and sensory input or emphasise the relevance of information processing biases. Postulated moderators range from maladaptive generalised beliefs over neurocognitive impairment to dopamine, stress, and affective dysregulation. The models also differ in whether they attempt to explain delusion formation in general or the delusional content (i.e., persecutory). Finally, some models postulate functional aspects of delusions, such as insight relief. Despite their differences, the perspectives converge on the idea that delusions form as an explanation for an experienced ambiguity. Building on this common ground, we propose an integrative framework incorporating essential mechanistic explanations from each perspective and discuss its implications for research and clinical practice.