Late in 1985 several thousand psychiatrists attended the Fourth World Congress of Biological Psychiatry in Philadelphia and heard several speakers claim that biological psychiatry had at last established its credibility. To some, this appeared an ambit claim but, to many, biological psychiatry was clearly the new Zeitgeist to be embraced. While post-congress triste may have reduced the infatuation for many, it is clear that biological psychiatry is entering a major growth phase.