The Academy for Eating Disorders, AED, takes the position that eating disorders are “biologically based” (Klump, 2009, p. 97) due to the findings from twin studies research. This position is supported by the longitudinal study conducted by Patton and colleagues (1999), in which they hypothesize there are biological predictors in the development of eating disorders among adolescent girls
Incidences of Anorexia Nervosa have appeared to increase sharply in the USA, UK and western European countries since the beginning of the 60s (Gordon, 2001). The increasing prevalence of the disease has led the World Health Organisation to declare eating disorders a global priority area within adolescent mental health (Becker et al. 2011). Anorexia has in many ways become a modern epidemic (Gordon, 2000) and with a mortality rate of 10% per decade (Gorwood et al. 2003), the highest of any mental disorder (Bulik et al. 2006), it is an epidemic that social and biological scientists have been working tirelessly to understand.
Bulik et al 2005 suggest that mothers with anorexia expose their offspring to a ‘double disadvantage’ & that nutritional factors may be implicated if mothers have an eating disorder – the transmission of genetic vulnerability to anorexia & inadequate nutrition during pregnancy.
Parallel to this, the focus on genetics is Particularly convicted in twin studies, which establish a comparison between monozygotic twins that are identical and dizygotic twins, which are opposingly non-identical. This distinction can be identified in Torgersens study, which compared MZ and same sex DZ twins where one proband had an anxiety disorder, and it was discovered that such disorders were 5x more frequent in MZ twin pairs, who mutually shared identical genetics.
Also the study was only done with twins and therefore the same results may not be found between parent and child etc, but the study does show that genetics can play a part in developing anorexia. For using concordance rates these studies can be criticised, since concordance rates alone cannot be to blame for twins developing an eating disorder, the causes can also be observational experiences/ learning such as constantly being surrounded by thin people and you are overweight.
It is believed that faulty genes can cause some disorders that have a psychological effect. A way in which this can be tested is by doing studies on twins as they have the similar genetics. McGuffin et al did a study in 1996 where they compared 109 sets of twins in order to investigate how likely each twin was to develop depression. They looked at the concordance rates for depression in MZ and DZ twins, they expected that MZ twins either both have depression or neither have depression. So therefore its expected to find a higher concordance for depression in MZ twins that in DZ twins. The results showed that if one non identical twin developed depression that there was a 20% likelihood that the other would too, in identical twins this rose to 46%. This study therefore proves that genetics can have a massive impact on abnormality.
While it has been long assumed that bulimia and anorexia have stemmed from insecurities and poor choices; DNA, genetics, endorphins, cholecystokinin, and CCK levels, among other things, are all important deciding factors of whether or not someone will be plagued with the diseases. Among the two, bulimia nervosa has had the most backed research on what could be the cause and nature of the disease. Bulimia Nervosa is a binge eating disorder. During these binges the participants eat without their food hormone receptors turning off resulting in them eating more than what would be FDA approved. After one of their binges they quickly purge themselves in a hope to lose the weight they gained during their binges. Pinpointing the causes of it have proven difficult because the disorder has both mental and psychical components, and it develops in
The inaccurate obsession with food seems to be the cause of bulimia; however, the inaccurate obsession with weight seems to be the cause of anorexia. A majority of research suggest that the media is responsible for this, due to the fact they idolize the thin, slender figure. For bulimics, the delight of binging comes at the cost of extreme guilt which can only be resolved by purging; a never ending cycle. For anorexics, these thin messages on the media can make them feel shameful and hate to look at their own body, which makes food the sworn enemy. In one research article it was proposed that individuals with an external locus of control (believing that their lives are determined by outside forces such as fate and other people) were found to exhibit more of the bulimic and anorexic traits than those individuals who had an internal locus of control (believing that one controls his/her own fate) (Fouts and Vaughn, 2002).
Researchers have discovered an area on chromosome 1 that appears to be associated with an increased susceptibility to anorexia. Others can suffer from psychological reasons. People that feel low self-worth sometimes become anorexic to make themselves feel better. Anorexia’s may have an extreme drive for perfectionism, which means they may never thing they’re thin enough. A lot of people suffer because of sociocultural reasons. The media is filled with images of thin models and actors, which associates success and worth with being thin. Peer pressure from friends, coworkers, and classmates also causes some people to feel there not fitting it.
Another study strategy to demonstrate the genetic component of a disease, and help to discriminate it from the environmental component is the twin study, which compares the correlation to the disease between monozygotic (MZ), with concordance among dizygotic twins (DZ). This type of epidemiological study 7parte the assumption that twins MZ and DZ suffer similar environmental influence, however, the MZ are genetically identical while the DZ not necessarily presenting genetic identity as similar as two brothers generated at different
Along with Florida State University psychology professor Pamela Keel, PhD, Klump is now using those findings to examine how natural changes in ovarian hormone levels may contribute to bulimic behaviors in twins. Preliminary analyses suggest that heritability influences disordered eating most when estrogen levels are at their highest. Klump is also involved with a study of the genetic underpinnings of anorexia conducted by University of North Carolina at Chapel Hill psychologist Cynthia Bulik, PhD, and other researchers from around the world. As part of a 13-country Genetic Consortium for Anorexia Nervosa, they plan to conduct the largest ever genomewide association study for the disorder, pulling together resources and DNA samples of more than 4,000 females with anorexia and 4,000 controls. However, new and as-yet-unpublished fMRI brain imaging work by Oregon Research Institute psychologist Eric Stice, PhD, suggests that in some females, bulimia may be hard-wired. Stice examined brain activation among 33 female adolescents and 43 young women after they tasted a chocolate milkshake. Over a one-year follow-up period, he found that those who showed greater activation of key reward regions in the brain—particularly the gustatory cortex, somatosensory cortex and striatum—reported increases in bulimic behavior. Similar research by Columbia University's Rachel Marsh, PhD, shows that the
The cause of anorexia is complex and unclear, but there is evidence to support that the illness has a genetic and sociocultural components, and that individuals with anorexia share common personality traits as well. Evidence supports that illness is inheritable and runs in families. An
Many researchers have found that genetics are linked to eating disorders. Studies have shown that genetics are responsible for 56% of the onset of bulimia, anorexia, and binge eating (Johnson and Bulik). The Eating Disorder Review said that a person is four times more likely to become bulimic and twelve times more likely to become anorexic if he or she has a sister or mother who suffers from an eating disorder (Kittleson 44). Studies of identical twins have also
a. According to Doctor Thomas Insel and director of NIMH, scientist and researchers have always been interested in the role of genetics on eating disorders but they are still far away from knowing specific geneses that causes eating disorder
Eating disorders tend to run in families and female relatives are the most often to be affected. Some recent studies from researchers found that mothers who are too concerned about their children’s weight and appearance, it may put them at increased risk of developing an eating disorder. (Hoffman). Ultimately, genetic research may prove to be the key to unlocking our understanding of environmental risk factors for eating disorders (Mazzeo and Bulik). Multiple studies have been undertaken to that show possible genetic likeliness toward developing eating disorders as a result of inheritance (News Medical).