Causes of Mental Disorders - Genes

Genes

Family-linkage and twin studies have indicated that genetic factors often play an important role in the development of mental disorders. The reliable identification of specific genetic susceptibility to particular disorders, through linkage or association studies, has proven difficult. This has been reported to be likely due to the complexity of interactions between genes, environmental events, and early development or to the need for new research strategies. The heritability of behavioral traits associated with mental disorder may be greater in permissive than in restrictive environments, and susceptibility genes probably work through both "within-the-skin" (physiological) pathways and "outside-the-skin" (behavioral and social) pathways. Investigations increasingly focus on links between genes and endophenotypes—more specific traits (including neurophysiological, biochemical, endocrinological, neuroanatomical, cognitive, or neuropsychological)—rather than disease categories. With regard to a prominent mental disorder, Schizophrenia, for a long time consensus among scientists was that certain alleles (forms of genes) were responsible for schizophrenia, but some research has indicated only multiple, rare mutations thought to alter neurodevelopmental pathways that can ultimately contribute to schizophrenia; virtually every rare structural mutation was different in each individual.