Schizophrenia is a severe psychiatric disorder with a lifetime prevalence that ranges between 0.5% and 1%. Many aspects of its etiology and pathophysiology remain poorly understood despite extensive research. The considerable contribution made by genetic factors to the vulnerability to schizophrenia is, however, well recognized. The heritability of schizophrenia is around 80%, and a first degree relative has a 5- to 10-fold increase in the risk of developing the disorder compared to the risk for the general population (Cardno and Gottesman, 2000; Sullivan et al., 2003). Beside genetic factors, environmental factors are also involved in the etiology of the disease. We will briefly review the formal genetic evidence available for schizophrenia and then provide an overview of the most significant molecular genetic findings, with an emphasis on how the latest findings obtained using array-based technologies have challenged our understanding of the genetic architecture underlying schizophrenia. We will also discuss how these new approaches may assist in comprehensively re-examining pathophysiological hypotheses such as the dopamine hypothesis of schizophrenia.
