Genotypes, phenotypes, and the brain. A search for connections in schizophrenia.

Abstract

The history of psychiatric research on genotypes, phenotypes, and the brain reveals much about the role of these concepts in our past and current understanding of schizophrenia and other psychiatric illnesses. Although interest in each topic is old by the standards of our young science, all have waxed and waned in their influence during our brief history. By ‘genotype’ I mean the hereditary constitution consisting of the genetic code, and by ‘phenotype’ I mean the physical expression of those genes throughout the life cycle of the individual. The relevance of the genotype to our field was recognised during the time of Charles Darwin, and reflected in the views of Henry Maudsley. Early optimism about the role that genetics would play in our understanding of mental disorder was tempered by the failure to find patterns of inheritance that corresponded to those described by Mendel. Enthusiasm about the study of genetic influences on human attributes was further attenuated when pseudo-genetics was embraced as a rationale for the horror of genocide. There has been a long and honourable history of genetic research in psychiatry, sustained by individuals such as Dr Eliot Slater (the 35th Maudsley lecturer and then Director of the Medical Research Council Psychiatric Genetics Research Unit at the Maudsley Hospital), but a renewal of the early excitement about genetic research has been engendered largely by recent developments in molecular biology.