Multi-level models of information processing, and their application to psychosis

Multi-level models have been developed to illustrate the mind's processing of qualitatively different types of information, and therefore provide a useful tool for exploring the actions and interactions of different processing levels within a single theoretical framework. This paper firstly reviews a selection of multi-level models, and then constructs a detailed rationale for applying a multi-level framework to psychosis. The argument draws on a wide psychosis literature, in the areas of positive symptoms, subjective phenomena, risk factors, and cognitive phenomena. In doing so, the discussion highlights some limitations of current (single-level) cognitive models of psychosis, and argues that a multi-level framework not only offers enhanced explanatory power, but also facilitates an integration of the evidence accumulated in different areas of psychosis research. Implications of a multi-level approach are discussed with regards to understanding the 'psychotic-like' experiences of both clinical and non-clinical populations. In particular, the roles of emotional meaning and function of psychotic phenomena are emphasised, and the clinical therapeutic tenet of normalisation is encouraged.