At least 40 million people in the worId suffer from the most severe forms of mental disorder such as schizophrenia and some 300 million more are affected by less severe but still incapacitating forms of these conditions, including, for example, drug and alcohol dependence and the consequences of brain trauma. The enor mous magnitude of human suffering and the economic losses usually linked of these disorders make them a problem of major public health importance. Recent years have brought with them scientific discoveries which have made it possible to successfully treat most mental disorders and to prevent many others. Some of them, however, cannot be prevented on the basis of today's knowledge, and their treatment remains palliative: further progress in their management awaits an improvement in our understanding of mechanisms by which they come into existence and of factors which influence their course. Recent years have also seen a significant increase in knowledge about genetic factors influencing the occurrence and course of a variety of diseases, for example, cystic fibrosis, Duchenne type muscular dystrophy, thalassemia, and hyperten sion. Some of this knowledge and some of the methods that have been developed to obtain it could have direct relevance to the search for a c1earer comprehension of the pathogenesis of mental disorder.

Free radicals appear to play a mojor role in many neurological (and non neurological) dieseases. Both acute and degenerative disorders are thought to involve free radicals reactions in tissue injury (for a list see this book page 18). This issue is very important for basic science and for therapeuthic approach as well. In order to review and discuss the place of free radicals in psychiatry and neurology, a joint meeting was initiated by the World Health Organization and the Fondation Ipsen in Paris on June 17-18,1991. This book contains the papers presented during this meeting. Although the papers included in this volume have been produced in the framework of WHO/Fondation Ipsen review of knowledge about free radicals and brain disorders, they express the views of the individual authors rather than a consensus of the participants at the meeting. They do not necessarily represent the decision or stated policy of the World Health Organiszation or the Fondation Ipsen. The editors wish to express their appreciation to Mrs Mervaillie for the organization of the meeting and Mrs M.-L. Gage for her editorial assis tance. L. Packer, L. Prilipko, Y Christen Contents Free Radical Scavengers and Antioxidants in Prophylaxy and Treatment of Brain Diseases L. Packer ........................................... 1 Reactive Oxygen Species and the Central Nervous System B. Halliwell .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 . . . . . . . . .

Over the past few years, genetics research has been in a phase of remarkably sustained and continuous revolution. The advent of "new genetics" of recombinant DNA has resulted in new discoveries occurring at a breath taking pace, many of which have important clinical implications, for example, in new approaches to the diagnosis and treatment of hemoglobinopathies, cystic fibrosis and some forms of muscular dystrophies. Recent findings of psychiatric relevance have included the localization of the genes for Huntington's chorea and the use of DNA probes in predictive testing. Advances have been achieved in the understanding of the molecular biology of Alzheimer's disease, and at least some familiar forms of the condition appear to be linked to a gene of chromosome 21. Taking into account current achievements in molecular genetics as well as future findings, it can be predicted that the application of new genetic technologies is likely to lead to ethical problems in practical psychiatry. In order to initiate discussions aiming to generate ideas and develop the background for future consensus in the complex area of ethics relating to the application of molecular approaches in the study of psychiatric disorders, the World Health Organization, in collaboration with the IPSEN Foundation, organized in Brno, Czechoslovakia, June 11-12, 1990, an international conference to review knowledge related to molecular genetic studies in psychiatry, with particular reference to ethical problems.