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.

Cardiovascular diseases are the principal cause of mortality in many developed countries and are increasing in importance in developing countries where communicable diseases are being brought under control. It is estimated that coronary heart disease (CRD) and cerebrovascular diseases are responsible for between 40-50% of all deaths. Righ blood pressure is common in all industrialized societies and contributes importantly to CRD. It is well known that genetic factors play an important role in the etiology and pathogenes es of cardiovascular diseases and contribute to an individual's susceptibility or resistance to the disease. The application of modern genetic techniques has resulted in the identification of polymorphie markers that are involved in the normal regulation and function of the cardiovascular system. Many of these may contribute to the individual differences in the risk for CRD and hypertension. It is now known that several risk factors or protective factors with respect to cardiovascular diseases are strongly influenced by genes, and it is now possible to identify individual genes contributing to cardiovascular risk. A large bank of genetic knowledge relevant to CRD and hypertension has become available during the past years. As a result, it is now believed that CRD, for example, could be a good model for a feasibility study to determine a way by which preventive measures can be applied.

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.