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Biological Explanations Of Anorexia Nervosa Essay

Anorexia and Bulimia Nervosa: Explanations

Explanations Of Anorexia Nervosa


Modern biological models see the hypothalamus as being involved in AN. This part of the brain plays an important role in the regulation of eating. Kaplan & Woodside (1987) showed that when the neurotransmitter noradlrenaline acts on part of the hypothalamus, animals begin eating & show a marked preference for carbohydrates. The neurotransmitter serotonin, by contrast, seems to induce satiation & suppress the appetite.

Any condition which increased the effects of serotonin would then decrease eating. However, Hsu (1990) has noted that there is not yet sufficient evidence to indicate whether change in a neurotransmitter levels are a cause of anorexia, an effect or merely a correlate.

Genetic Explanation

Strober & Katz (1987) have shown a tendency for anorexia to run in families, with first & second-degree relatives of anorectics significantly more likely to develop the disorder as compared to the same degree relatives of non-anorectics (control group).
Askevold & Heiberg (1979) have reported a 50% concordance rate for MZ twins brought up in the same environment. Hollander et al (1984) a rate of 55% for MZ twins and 7% for DZ twins. However, in the absence of concordance rates for MZ DZ twins reared apart, the evidence is difficult to evaluate.

Although the evidence hints at a genetic role in anorexia, as Treasure & Holland (1991) have noted, it is likely to be a small one.


The biological explanations make a contribution to the understanding of eating disorders, but other factors are involved and several questions are left unanswered:

  1. Why are some personality characteristics found to be associated with the conditions?
  2. Why are young women the more susceptible group?
  3. Why are eating disorders on the increase?


Behavioural Explanations
Suggests that slimming becomes a ‘habit, just like any other habit through stimulus response mechanisms (classical conditioning). The person first goes on a diet & after a while receives praise from others, either for their attempts or their new slimmer appearance.

Operant Conditioning then takes effect as the admiration from others further reinforces their dieting behaviour. Rewards may also come in the form of attention gained from parents by not eating.

Supporters of the Behavioural Model also propose anorexia as a phobia concerning the possibility of gaining weight. Crisp (1967)suggested that anorexia might be more appropriately called weight phobia. The phobia is assumed to be the result of the impact of social norms, values & roles.

Garner et al (1980) discovered that the winners of Miss America & the centrefolds in Playboy magazine have consistently been below the average female weight & have become significantly more so since 1959. Thus the slender female perceived as being the cultural ideal might be one cause of the fear of being fat.

The Media & Social Norms

According to Hill (1996) women’s fashion magazines play a part in shaping young girls’ perceptions of desirable figures. If women are encouraged to
see slimness as desirable through its promotion in the media, then seeing their bodies as larger than they are (distorted body image) may encourage dieting to try to achieve that goal.

In one study of media influence, Hamilton & Waller (1993) show eating-disordered & non-eating-disordered women photographs of idealised female bodies as portrayed in women’s fashion magazines. The NED women were not affected by the nature of the photos they saw. However, the ED women were, & over-estimated their own body sizes more after they had seen such photos than after they had seen photos of neutral objects.

Fear (1999) describes a sudden increase in eating disorders among teenage girls in Fiji which may be linked with the arrival of television on the island in 1995. Since TVs introduction, there has been a sharp rise in indicators of disordered eating. 74% of Fijian teenage girls reported feeling ‘too big or fat’ in a 1998 survey conducted 38 months after the country’s one television station began broadcasting. Traditionally, Fijians have preferred a ‘robust, well-muscled body’ for both sexes.

However, one puzzling observation that is difficult for theorists to account for is the development of the disorder in blind people as body image disturbance is one of the hallmarks of anorexia.Yager et al (1986) have described the case of a 28-year-old woman, blind from the age of 2, who had become anorectic at age 21.
Touyz et al (1988) reported a case of anorexia in a woman who had been blind from birth.
Further support for the claim that societal norms can be extremely influential comes from evidence about eating disorders in other cultures. Lee et al (1992) have shown that in at least some non-western cultures (including China, Singapore and Malaysia) the incidence of anorexia is much lower in Western societies.


There are several explanations of AN based on the psychodynamic model. One proposes that the disorder represents an unconscious effort by a girl to remain pre-pubescent. As a result of over dependence on the parents. Some girls might fear becoming sexually mature. Since AN is associated with menstrual periods stopping, psychodynamic theorists see this as enabling the anorectic to avoid growing up.

Another psychodynamic account proposes that the disorder may allow a girl to avoid the issue of her sexuality. The weight loss that occurs prevents breasts and hips from becoming rounded, dt the body takes on a ‘boy-like’ appearance. Psychodynamic theorists propose that this might be a, way of avoiding the issue of sexuality in general & the prospect of t pregnancy in particular.

A third psychodynamic account see AN as an attempt by adolescents to separate themselves from their parents & establish their own identities. Bruch (1991) argues that the parents of anorectics tend to be domineering, and the disorder represents an attempt to gain a sense of autonomy and control as ‘such children experience themselves as not owning their own bodies’. One way of exerting individuality is to assume control over what is most concretely one’s self – the body. Thinness &
starvation are signs of self-control & independence.


Cognitive theories emphasise the thought processes of a person with an eating disorder, i.e. over-concern with the importance of body weight & shape. Beck et al (1979) found that people who were having psychological difficulties in life often had unrealistic expectations about themselves.

Garner ei Bemis (1982) have applied some of Beck’s theory to eating disorders. Typical cognitive distortions of patients with anorexia (or bulimia) nervosa are: ‘People will only love me if I am thin.’ ‘I was unhappy when I was a normal weight’.

Fairburn (1989) found that most patients with eating disorders admit they are unlikely ever to be completely satisfied with their shape & weight. If these patients continue to determine their self-worth through body shape, they are likely to continually suffer from eating disorders & remain unhappy.

These distorted thought processes lead the patient to adopt strict, inflexible dietary rules. If the rules are broken, the sufferer will experience a sense of failure & a decrease in self-esteem.

Family Systems Theory
Minuchin (1978) suggests that the development of anorexia serves the function of preventing conflict within the family. For example, it may be the adolescent’s way of preventing a marriage break-up by diverting attention onto him/herself. In doing so, the hope is that joint concern for the child will bring the parents back together.

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Psychology - Biological Explanation of Eating Disorders Essay

1011 WordsMar 26th, 20135 Pages

Psychology Essay
The biological approach suggests that AN is due a physical cause, suggesting it could be due to something within the body or brain; such as hypothalamus dysfunction or an imbalance of neurotransmitters.
The hypothalamus dysfunction theory would suggest that animals have a “set weight” which is correct for their body, if this weight should increase or decrease then the body should make adjustments to regulate food intake to their “set weight”.
The hypothalamus is thought to have quite a lot of control over our eating behaviour, the lateral hypothalamus (LH) is considered to be the feeding switch that makes an individual begin to feed whereas the ventromedial hypothalamus (VMH) is the satiety switch that makes an…show more content…

This research would also support the biological explanation of AN as if an individual has damage to their hypothalamus then it could result in reduced feeding which would then result in dramatic weight loss, as seen in sufferers of AN. However, this theory is reductionist as it suggests that the only explanation of AN is a biological reason, and it ignores other factors; like things such as stress or sexual abuse which can both lead to AN.
Another biological explanation of AN would be that there is an imbalance of serotonin, which is usually associated with depression and anxiety; as disturbed levels of serotonin have been found in AN sufferers. It is also likely that eating disorders arise due to high levels of anxiety which is linked with high levels of serotonin in the body.
Bailer et al (1970) compared serotonin activity in recovering anorexia suffers and healthy controls. They found significantly higher activity in the women that were recovering from anorexia, the highest levels found in those women with the highest anxiety levels. This also provides support for AN having a biological cause, in this case an imbalance of neurotransmitters.
However, it’s difficult to establish cause and effect in Bailer’s research, this is because the women studied were already recovering from an eating disorder and so it’s impossible to know whether the imbalance of serotonin was the cause of the women’s AN or whether the AN causes an imbalance of

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