British Journal of Psychiatry, 186(3), March 2005, pp.179-181.
Publisher:
Cambridge University Press
It is probable that the genetic components of affective disorders (bipolar affective disorder, major depressive disorder and anxiety states) result from multiple genes conferring susceptibility or liability to develop the disorder when other (environmental) risk factors are also present. In general, bipolar affective disorder has been found to have the highest heritability (the proportion of variance explained by additive genetic factors) of around 80%, followed by major depression (40-70%) and anxiety disorders (40-50%). For affective disorders in adult life the role as precipitants of certain proximal factors such as severe and threatening life events has been well replicated. There is also much evidence of distal factors such as childhood adversity contributing to vulnerability. Important
It is probable that the genetic components of affective disorders (bipolar affective disorder, major depressive disorder and anxiety states) result from multiple genes conferring susceptibility or liability to develop the disorder when other (environmental) risk factors are also present. In general, bipolar affective disorder has been found to have the highest heritability (the proportion of variance explained by additive genetic factors) of around 80%, followed by major depression (40-70%) and anxiety disorders (40-50%). For affective disorders in adult life the role as precipitants of certain proximal factors such as severe and threatening life events has been well replicated. There is also much evidence of distal factors such as childhood adversity contributing to vulnerability. Important developmental aspects include continuities between childhood depressive symptoms and adult depression and changing contributions of genes and environment throughout the life span. For example, recent findings support and extend earlier work that has shown increasing genetic influence on depressive symptoms as children grow into adolescence. With the completion of the sequencing of all the base pairs in the human genome we are entering a ‘post-genomic’ era, although identifying the genes involved in the aetiology of affective disorders remains a major research pre-occupation. However, many geneticists as well as researchers from other disciplines are turning their attention to environmental risk factors and how these interact and co-act with genes to lead to the expression of pathological phenotypes such as depression. Although genetic variation in humans can now be determined relatively easily from a single DNA sample derived from blood or even scrapings from the inside of the cheek, experimental manipulation of the environment of human subjects is clearly not possible. Consequently, alternative methods are required to measure the ‘environment’. One is to examine the genotypes of individuals who have all been exposed to a specific risk factor, such as childhood adversity or severe threatening life events, comparing those who have expressed the phenotype, for example by becoming depressed, and those who have not (resilient individuals). Some longitudinal and twin studies, as well as others currently being conducted, will lend themselves to this type of analysis.
Great Britain. Welsh Office. NHS Directorate. Welsh Health Planning Forum
Publication year:
1995
Pagination:
520p.,bibliog.
Place of publication:
Cardiff
Set of papers compiled by the Health Gain Panel of Review with the aim of improving the provision of services to people with mental health problems in Wales. Includes sections on: the epidemiology of mental illness; promoting mental health; mixed anxiety depressive syndrome; depression; bipolar affective disorders; schizophrenia; dementia; personality disorders; suicide and parasuicide; eating
Set of papers compiled by the Health Gain Panel of Review with the aim of improving the provision of services to people with mental health problems in Wales. Includes sections on: the epidemiology of mental illness; promoting mental health; mixed anxiety depressive syndrome; depression; bipolar affective disorders; schizophrenia; dementia; personality disorders; suicide and parasuicide; eating disorders; child and adolescent mental health; older people with mental health problems; homelessness and mental health; and therapies.
Subject terms:
homelessness, mental health, mental health problems, mental health services, older people, personality disorders, schizophrenia, severe mental health problems, suicide, young people, anxiety, children, dementia, depression, eating disorders, family therapy;