Psychosis is a disordered mental state, which is core to psychiatric conditions such as schizophrenia and leads to distress and impairment. Individuals who suffer from psychosis typically experience hallucinations and delusions. My main line of research addresses the following: what psychological processes predict the development of psychosis and maintain these symptoms despite medication? My samples span from patients across acute and stable stages of illness, to non-clinical participants with a high risk of developing psychosis, and healthy individuals. We have adopted multiple methods of inquiry, including clinical interviews, neurocognitive assessment, experience sampling, meta-analysis, and randomized controlled treatment trials.