[Genetic foundations of vulnerability to depression].
Depression is a complex phenotype probably heterogeneous in its biology and in its aetiology. Genetic studies have contributed to clarifying some aspects of that heterogeneity, but we are still far from being able to establish its molecular foundations, although a certain degree of genetic variability in genes of the serotoninergic system appear to contribute to the risk of the disease and to certain of its clinical aspects. The risk of a major depressive episode increases in relation to the number of genes shared with an affected person but, in genetic terms and given the differential risks found, there is also a certain overlap with bipolar disorder and schizophrenia. These data lead to reflection on the meaning of genetic risk detected in families and its specificity. Perhaps genetic studies will have to leave the categorical definition of phenotypes and begin to use the dimensions of psychopathology for delimiting the biological and genetic subgroups present in functional psychoses.
Fañanás
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Departmento Biología Animal, Facultat de Biología, Universitat de Barcelona, 08028 Barcelona.