The field of research in 5-hydroxytryptamine has exploded into furious activity over the past decade and nowhere have the implications been more far reaching than in psychiatry. Thanks largely to the introduction of radioligand binding techniques, a bewildering variety of 5-hydroxytryptamine receptors has been revealed, and powerful new families of centrally-active drugs have emerged. The importance of these new discoveries for psychiatric practice can hardly be exaggerated. To mention but one example, our understanding, and with it the treatment, of obsessive-compulsive disorder has been transformed in a very few years. The excitement continues, and almost daily, some important new insight, usually drug led, alters our whole perception of psychiatric illness. Due to this activity, the CINP chose 5-hydroxytryptamine and Psychiatry as the topic for its first President's Workshop.The CINP is an international neuropharmacological organization renowned for its massive, comprehensive, and prestigious biennial congress. It recently decided to complement these with a different type of gathering, a small brain-storming meeting, dominated by a free-flowing discussion. The record of this first President's Workshop is recorded here. The contributors were all hand-picked, and are active researchers with a distinguished track record. They have all contributed substantially to the burgeoning 5-hydroxytryptamine field. The free-ranging style of this volume and the many good ideas presented cannot fail to be of major interest to all who wish to keep abreast of this rapidly moving area of research.