This editorial reviews the relationship between childhood trauma and the development of psychosis in adulthood. There are numerous studies, including large, prospective studies, which clearly support a link between childhood adversity and experience of psychosis later in life. There is also evidence that there is a dose response relationship, and that childhood trauma is particularly associated with the experience of hallucinations and delusional ideas. It is possible that psychosis is a relatively understandable response to the experience of severe trauma, and recent cognitive models of psychosis can help to explain the underlying mechanisms in such a causal relationship. There are obvious treatment implications, which include the need to assess histories of childhood trauma in people with psychosis, the incorporation of trauma in shared understandings of psychosis with service users, the incorporation of change strategies in cognitive behaviour therapy for psychosis that are derived from evidence-based approaches to the treatment of trauma and PTSD, and the prevention of traumatisation by mental health services.Declaration of Interest: None.