Genetics of developmental psychiatric disorders: pathways to discovery.

Genetics has captured the imagination of the public, the interest of the media and a large place in the sciences. Since the discovery of the structure of DNA by Watson and Crick, the double helix has epitomized the main dogma of genetics: everything from the tiniest details of the human body to the most complex of behaviours is encoded in the genes. This belief has been strengthened by the tremendous success that has been achieved in cloning more than 1000 genes that cause simple Mendelian disorders. However, for complex disorders, particularly psychiatric conditions, the search for genes has been frustrating and has not yielded definitive results, although claims of gene discoveries are made regularly. In this article, we discuss the possible causes for these difficulties, along with some directions that may help in reducing these problems. We also consider the implications of psychiatric genetic research for individual and public health.