The document discusses eating disorders and their biological causes. It describes the three main types of eating disorders - anorexia, bulimia, and binge eating - and their defining characteristics. It then explains several biological factors that may contribute to eating disorders, including heritability, hypothalamic activity, serotonin levels, estrogen levels, and irregularities in neurotransmitters like dopamine and cortisol. Genetics and hormones like estrogen appear to make some individuals more susceptible during puberty.

1. Presented by :
I.Vidya Sree
1225612104
M.Sc. Applied Psychology
GITAM Institute of
Management

2. Introduction to Eating Disorders
• Eating disorders are one of the unspoken
secrets that affect many families.
• Rarely talked about, an eating disorder can
affect up to 5 percent of the population of
teenage girls because during this period
women are more likely to diet to try and keep
a slim figure and try stringent dieting.

3. Classified into 3 types:
There are three main types of eating disorders:
• Anorexia
• Bulimia
• Binge Eating

4. Anorexia
• Anorexia (also known as anorexia nervosa) is
the name for simply starving self because you
are convinced you are overweight.
• If you are at least 15 percent under your
normal body weight and you are losing weight
through not eating, you may be suffering from
this disorder.

5. Bulimia
• Bulimia also known as bulimia nervosa is
characterized by excessive eating, and then
ridding yourself of the food by vomiting,
abusing laxatives or diuretics, taking enemas,
or exercising obsessively. This behavior of
ridding yourself of the calories from
consumed food is often called "purging."

6. Binge Eating
• A person who suffers from this disorder can
have it go undetected for years, because the
person's body weight will often remain
normal.
• "Binging" and "purging" behavior is often
done in secret and with a great deal of shame
attached to the behavior. It is also the more
common eating disorder.

7. Biological Causes of Eating Disorder
Research supports that there are complex
interactions accountable for one’s predisposition
to develop an eating disorder, certain factors
which play an important role are:
• Heritability
• Hypothalamic activity
• Serotonin
• Estrogen
• Neurotransmitters

8. Heritability
• A study found that genetic linkage on
chromosome 1 might play a role in having a
genetic predisposition for anorexia nervosa.
• It is likely that several genes are responsible
for predisposing one to anorexia as well as
bulimia nervosa.

9. Contd..
• Having a mother or a sister with anorexia
nervosa makes one twelve times more likely
to develop anorexia and four times more likely
to develop bulimia nervosa than individuals
without a family history of anorexia nervosa.

10. Hypothalamic activity
• Hypothalamus is responsible for regulating
hunger.
• Research indicates that the hypothalamus
found in bulimic individuals may not trigger a
satiation response after eating a meal, thus
induce a binge-eating episode .

11. Serotonin
• Irregular levels of serotonin may play an
important role in binge-eating episodes.
• The body converts carbohydrates into sugars,
which are then converted into tryptophan.
• Tryptophan in turn is used to produce
serotonin, which plays an important role in
the regulation of mood and appetite.

12. Contd..
• Bulimic individuals often crave foods rich in
carbohydrates, suggesting low levels of
serotonin in the brain.
• A decrease in bing-eating episodes has been
seen in bulimic individuals taking antidepressants that specifically target serotonin.

13. Contd..
• The relationship between serotonin and anorexia
nervosa remains unclear.
• Some anorexic individuals have been found to
have abnormally high levels of serotonin, which
induces stress and anxiety.
• Minimal eating would allow for a decrease in
anxiety by decreasing levels of serotonin in the
brain. However, SSRIs such as Zoloft and
Prozac—causing an increase in serotonin levels—
have effectively treated anorexic individuals.

14. Contd..
• Abnormal eating patterns and associated body
changes can alter serotonin levels, thus
contributing to preexisting abnormal
levels. Abnormal serotonin levels can also
lead to depression and anxiety disorders.

15. Estrogen - estradiol
• Scientists have discovered a possible biological
culprit in the development of eating disorders
during puberty: a type of estrogen called
estradiol.
• Estradiol is the predominant form of estrogen
in females.
• It is responsible for the growth of reproductive
organs and also influences other organs
including bones.

16. Contd..
• Kelly Klump, associate professor of psychology at
Michigan State University, and colleagues found
that genetic influence on eating disorder
symptoms was much greater in pubertal girls
with higher levels of estradiol than pubertal girls
with lower levels of the hormone.
• The study examined the estradiol levels of nearly
200 sets of female twins, ages 10-15, from the
MSU Twin Registry, which includes more than
5,000 pairs of twins in Michigan.

17. Contd..
The reason in an increase in genetic influences
during puberty is that the genes for
disordered eating are essentially getting
switched on during that time and it was found
that increases in estradiol apparently are
activating genetic risk for eating disorders.

18. Neurotransmitters
• Irregular levels of dopamine have been found
in women with anorexia nervosa.
• Dopamine is responsible for feelings of
pleasure and provides feelings of reward
associated with certain tasks, in turn
motivating us to perform these tasks.
• Thus, anorexic women’s drive to lose weight
but lack of satisfaction after loosing weight
may be a result of irregular dopamine levels.

19. Contd..
• High levels of cortisol have been found in bulimic
and anorexic individuals.
• Levels of cortisol increase as a response to stress
in order to prepare the body to respond to a
threat. Release of cortisol also decreases
appetite.
• However, cortisol levels have been shown to
increase after the development of an eating
disorder, so whether it plays a causal role or is a
consequence of an eating disorder is unclear.

20. Contd..
• Eating disorders may result in a drop in leptin
levels due to the loss of large amounts of fat.
• Leptin tells the brain how much energy is
available for use and plays a role in regulating
“reproduction, appetite, metabolism, and
bone formation.”
• Drops in leptin levels can stop a woman’s
menstrual cycle, result in bone loss or
impaired metabolism.