Schizotypy and substance use

Psychological models view delusions as, on a continuum with normal beliefs, multidimensional, attempts to make sense of anomalous experiences, mediated by maladaptive appraisals, involving reasoning and cognitive biases and influenced by emotional processes. Psychological approaches to delusions have typically adopted a 'continuum' model, which denies categorical distinctions between delusional and everyday beliefs, and, in doing so, challenges the traditional notion that having a diagnosed psychotic condition is qualitatively different from normal human experience. This chapter outlines the dimensions of delusions that are most commonly acknowledged in the literature. For each belief dimension, the individual variability among clinical populations will be explored, as well as its continuum with normal ideation. The chapter explores the implications of dimensional approaches to delusions in terms of psychological formulation and interventions. The role of emotions in delusion formation is gathering increasing attention in the psychological literature, with empirical evidence that negative emotions drive paranoid appraisals, rather than the other way round.