previous post) has an interesting PPP article on delusions. Delusions are failures of communication characterised by a disturbance of transcendental intersubjectivity. People do not "passively receive information from their environment which they then translate into internal representations. Rather, ... they constitute their experienced world or Umwelt through their ongoing sensorimotor interaction and embodied coping with the environment". Reality is constituted through active shifting of moving and multiple points of view reinforced by social perspective-taking.
Psychosis involves a radical subjectivisation of the processing of information so that understanding loses its intentional and decentering structure and the person adopts a solipsistic self-centrality. Basic trust in the shared world has been lost. A new sense-making is established fundamentally decoupled from the shared world (see previous post). "The possibility of intersubjective understanding is ... sacrificed for the new coherence of the delusion".