ABSTRACT
Hypotheses concerning the etiology and pathophysiology of schizophrenia are legion, but the origins of this disorder remain unknown. Furthermore, as there are no objective, laboratory-based diagnostic tests for schizophrenia; diagnosis is based on patterns of symptoms, signs, and other historical variables. Given these problems, the disorder we know as schizophrenia should be thought of as a syndrome, covering a range of conditions that are heterogeneous in terms of symptoms, course, outcome, response to treatment, and probably etiology. Nevertheless, with the use of structured and semistructured interviews and explicit operational diagnostic criteria, it is possible to diagnose the disorder with a high degree of reliability, and, as we shall show below, the syndrome so defined has a high heritability thus allowing the possibility of dissection of schizophrenia by genetic investigation. However, as in all areas of schizophrenia research, the likely etiological heterogeneity of the disorder poses a formidable obstacle to progress, and disappointments abound in schizophrenia genetic research, particularly in the field of molecular genetics. Nevertheless, progress has been made and we remain optimistic that schizophrenia will succumb to the ever increasingly powerful tools available to geneticists. In this chapter, we review the current state of the field from the perspective of
psychiatric geneticists, consider some of the difficulties that lie ahead, and offer our opinion on the likely solutions and the trajectory that future research is likely to follow.
