This report provides an overview of the current state of knowledge about why some people hear voices, experience paranoia or have other experiences seen as 'psychosis'. It also describes what can help. In clinical language, the report concerns the 'causes and treatment of schizophrenia and other psychoses'. In recent years we have made huge progress in understanding the psychology of what had previously often been thought of as a largely biological problem, an illness. Much has been written about the biological aspects: this report aims to redress the balance by concentrating on the psychological and social aspects, both in terms of how we understand these experiences and also what can help when they become distressing. We hope that this report will contribute to a fundamental change that is already underway in how we as a society think about and offer help for 'psychosis' and 'schizophrenia'. For example, we hope that in future services will no longer insist that service users accept