Schizophrenia remains an important challenge to psychiatry, with its causes and underlying brain mechanisms yet to be fully revealed. Currently available treatments are neither universally effective nor without unwanted effects. These aspects, together with the high prevalence of schizophrenia, its often debilitating nature, and the associated family and social burden, make this mental disorder one of the most complex public health issues of our times.

The purpose of the Advances in Schizophrenia Research series is to provide comprehensive periodic reviews of the wide range of research studies carried out around the world, with the dual purpose of solving the schizophrenia puzzle, and providing clues to new forms of treatment and prevention for this disorder. A special feature of the series is its broad scope, virtually encompassing all fields of schizophrenia research: epidemiology and risk factors; psychopathology; diagnostic boundaries; cognition; outcome and prognosis; pathophysiology; genetics; pharmacological and psychological forms of treatment and rehabilitation; community care; and stigmatization.

Schizophrenia remains an important challenge to psychiatry, with its causes and underlying brain mechanisms yet to be fully revealed. Currently available treatments are neither universally effective nor without unwanted effects. These aspects, together with the high prevalence of schizophrenia, its often debilitating nature, and the associated family and social burden, make this mental disorder one of the most complex public health issues of our times. The purpose of the Advances in Schizophrenia Research series is to provide comprehensive periodic reviews of the wide range of research studies carried out around the world, with the dual purpose of solving the schizophrenia puzzle, and providing clues to new forms of treatment and prevention for this disorder. A special feature of the series is its broad scope, virtually encompassing all fields of schizophrenia research: epidemiology and risk factors; psychopathology; diagnostic boundaries; cognition; outcome and prognosis; pathophysiology; genetics; pharmacological and psychological forms of treatment and rehabilitation; community care; and stigmatization.

This book comprises the conferences and discussions presented at the 4th sym posium on the SEARCH FOR THE CAUSES OF SCHIZOPHRENIA, which took place in Guaruja, Brazil, November 1998. This series of symposia started in 1986, on the occasion of the 600th anniversary of the University of Heidelberg, followed by two others in 1989 and 1993. From these meeting resulted three volumes that have been widely used as a reference for comprehensive reviews on the state of the art in schizophrenia research. They reflect the progresses result ing from the most relevant studies on the etiology of the disease. The spirit of the 4th "Search for the Causes" remains the same: again we gathered some of the most prominent researchers on schizophrenia to contrib ute not only with their own data, but also summing up the state of the art and the perspectives in their areas of work. The topics covered in 6 parts are Epide miology, Risk factors and antecedents, Genetics, Neuropathology and neuro chemistry, Brain imaging and function, and Treatment and rehabilitation. In this 4th volume were introduced in each topic a chapter on the "Balance of the Cen tury," to summarize what did we learn (and what we did not) in the last 100 years of schizophrenia research. We hope that this volume can help us to see how far we are in the Search for the Causes of Schizophrenia and how much further we still have to go before our problem can be solved."

This volume presents the contributions to the third symposium on the "Search for the Causes of Schizophrenia". The first symposium was organized by the Central Institute of Mental Health on the occasion of the 600th anniversary of the University of Heidelberg in 1986. Its objective was to give an overview of the rapid development in schizophrenia research in a situation characterized by an excessive variety of methods and topics. It was our intention, through substantial contributions to topical areas of schizophrenia research and through intensive discussions, to further the exohange of hypotheses and results and thus open up ways towards new concepts integrating different methodological approaches or towards new models of explanation. The first symposium was a great success. The publication of the proceedings (Hafner et al. 1987) was received with enthusiasm and recommended in leading journals "as the best available state-of-the-art analysis of current research on the aetiology of schizophrenia". For this reason we held a second and a third symposium entitled "Search for the Causes of Schizophrenia" under the same auspices and at the same place in 1989 and 1993.