The last decade the development of the molecular biology has increased the interest in psychiatric-genetic research. This review describes in two parts the knowledge on the genetics of frequent psychiatric disorders. The contribution of genetic understanding of psychiatric disorders is emphasized, but also the complexity and the limitations of the methodology and the challenges for the future.
The first part summarizes the 'classical' clinical- and statistic genetic study methods (twin, adoption, family studies: segregation analysis). This is completed by moleculargenetic methods (localisation and identification of 'disease genes' by linkage analysis, gene identification and the analysis of the gene product). The evolving complexity of genetic counseling for psychiatric disorders is emphasized. Specific psychiatric disorders summarized in this part are the eating disorders, anxiety disorders and alcoholdependence. The second part describes the results for schizophrenia, mood disorders and Alzheimer's disease.