Psychosis is a recognised feature of several psychiatric disorders and it causes patients significant distress and morbidity. It is therefore important to keep knowledge of possible risk factors for psychosis up to date and to have an overview model on which further learning can be structured. This article concludes a three-part series. It gives a review of evidence regarding common pathways by which many risk factors come together to influence the development of psychosis and finalises our suggested overview model, a psychosis risk timeline. The three primary pathways considered are based on the major themes identified in this narrative review of recent literature and they focus on neurological, neurochemical and inflammatory changes. We link each back to the factors discussed in the first and second parts of this series that alter psychosis risk through different mechanisms and at different stages throughout life. We then consider and summarise key aspects of this complex topic with the aim of providing current and future clinicians with a model on which to build their knowledge and begin to access and understand current psychosis research and implications for future preventive work.