This volume is a compilation of the presentations and discus sions, arranged in a systematic manner, of the fifth symposium on the Search for the Causes of Schizophrenia, held in Guarujal Brazil in April, 2003. The meetings look back on a great tradi tion. The first symposium, held in 1986 on the occasion of the th 600 anniversary of the University of Heidelberg, was our first effort to assemble successful schizophrenia researchers to pre sent and discuss research results in a spirit overcoming meth odological boundaries and disciplines. The result was one of the most interesting and exciting...