1. PRESENTED BY: TAYLOR HARTMAN
Eating Disorders:
The Influence of Genetics in
Pathological Eating

2. Definition and Some Background
 Eating disorders (EDs) are serious psychiatric conditions
with significant morbidity and mortality; eating disorders
have the highest mortality rate of any psychiatric diagnosis.
 Many cases are likely not to be reported. In addition, many
individuals struggle with body dissatisfaction and sub-
clinical disordered eating attitudes and behaviors
 The best-known contributor to the development of anorexia
nervosa and bulimia nervosa is body dissatisfaction
 By age 6, girls especially start to express concerns about
their own weight or shape. 40-60% of elementary school
girls (ages 6-12) are concerned about their weight or about
becoming too fat.

3. Prevalence/Relevance
 The National Institute of Heath (2011) documented
that the average amount of research dollars per
affected individual with an ED was just $0.93.
 There were over 30 million documented cases of ED’s
in 2011.
 ED research funds from the National Institute of
Health only accumulated about $28,000,000 by 2011,
whereas Alzheimer's Disease has a prevalence of 5.1
million people and has an excess of over
$450,000,000 in research funds.
 Why do you think that there are few research funds
for ED’s?

4. Importance of Recognizing ED’s
 Believed to be a lifestyle. It’s a mental illness, a
silent killer
 Believed to be influenced by psychosocial (peers,
media, internalized thoughts) and genetic variables,
though the argument on genetics is still not
completely “accepted”
 There is a stigma that many ED’s are associated with
vanity, fashion, beauty, sex, etc.
 This belief can be blamed for the idealized media
portrayals in magazines, TV, movies, fashion, etc.
that is stereotypical in models, ballerinas, celebrities,
etc.

5. Females and Males
 Approximately 10% of eating disordered individuals
coming to the attention of mental health professionals
are male.
 Men may tend to be more fixated on bulking up,
increasing muscle mass.
 Females may tend to be more fixated on a drive for
thinness.
 The culture of the U.S. tends to emphasize a certain body
type on men and women, which is associated with
behaviors such as extreme femininity in females and
masculinity, toughness, and aggressiveness in males.

6. Context of ED’s
 The culture of body image, thin-ideals, muscular
bodies, etc. cause people to over-emphasize their
bodies in order to feel a certain way about their lives.
 Most of the time, ED’s involve a need to control
emotions, negative cognitions such as negative
thinking, catastrophe (worst case scenario) thinking,
etc.
 Therefore, pushing certain ideals into the media and
community skew and can push people who may be
predisposed genetically to carrying out ED
symptomatology.

7. Policy and Implications
 While it is popular to blame the media and cultural ideals
for disordered eating behaviors (DEB), body
dissatisfaction, eating disorders, and public policies
should be based on an understanding of these factors in
combination with personality, genetic, family, and peer
factors.
 The overemphasis on media influence, for instance, has
led to the conceptualization of eating disorders as
socially constructed illnesses. This has hindered access to
proper medical care such as that afforded to physical
illnesses and serious mental health illnesses.

8. Question
 Question:
 Because it is obvious that ED’s are associated
with media, peers, a culture of gendered
behavior, norms, and food, how much do
genetics actually influence ED’s?

9. Hypothesis & Prediction
 Hypothesis:
 Considering most mental illnesses are influenced by
biological predispositions and are connected to other
comorbid illnesses that are biological (depression,
anxiety, etc.), ED’s tend to have as much influence over
someone’s behavior as social stressors.
 Prediction:
 ED’s are connected to a strong genetic link in eating
pathology.

10. Study #1
 Genetic and Environmental Influences on Thin-
Ideal Internalization
 Method: 343 postpubertal female twins ( 12-22 years of age, M=
17.61)
 Researched female twins with disordered eating; require much time and
energy to do so.
 Use of a 9-item Socio-cultural Attitudes towards Appearance
Questionnaire-3 was utilized for social factors.
 Results:
 Monozygotic Twins were shown to have more shared internalization
of thin ideals than dizygotic twins.
 Personality traits were an outcome of research. It was believed that
perfectionism, influence individual differences which is known to be
heritable and may contribute to genetic variance on drive for
thinness.
 Disordered eating was found to be higher in Monozygotic twins than
the dizygotic twins.

11. Study #1 (cont.)
 Reliable?
 Not particularly. Media pressures could have been asked in an
interview or scale measure for comparison.
 Good exclusion/inclusion criteria.
 High reliability and validity od the scales used, however.
 Try males? Different ages?
 Type of Study?
 Open label trial, both knew the study
 Retrospective, looked at cognitions due to genetic links from
birth
 Future research design?
 Double blind, could help in eliminating bias, add more types of
sample sizes and diverse characteristics, comorbid disorders.

12. Study #2
 The Influence of Heritability, Neuroticism, Maternal Warmth
and Media Use on Disordered Eating Behaviors: A Prospective
Analysis of Twins
 Method: Takes data from a previous adolescent health
longitudinal study. 290 Monozygotic twins and Dizygotic
twins (580). Data from 1994-1995, follow up studies
 Average age at the time was 16, mostly Caucasian (23%), 50.3%
male
 Researched male and female MZ and DZ twins for concerns with
weight, disordered eating, using the Disordered Eating Behaviors Scale.
 Maternal warmth scale: perception of mothers love and support ,
school problems and difficulties, media use and and neuroticism were
collected for variance in answers, and for risk of developing a disorder.

13. Study #2 (cont.)
 Results:
 FEMALES:
 For females, genetic factors accounted for 40% of the
variance in DEB, with 7% due to shared non-genetic
factors. The remaining 53% of the variance was due to
non-shared non-genetic factors.
 MALES:
 For males, results were similar with genetic factors
accounting for 48% of the variance, shared non-genetic
accounting for 5% of the variance and non-shared, non-
genetic factors accounting for the remaining 47%.

14. Study #2 (cont.)
• Genetic Heritability was found to be a stronger predictor of disordered
eating , followed by sex, implying that genetics play a bigger role than
whether or not the person is female or male.

15. Study #2 (cont.)
 Reliable?
 Yes, considered great sample size, type, ages, etc. Longitudinal and
reoccurring tests for follow ups over the years of adolescents and young
adulthood.
 High reliability and validity od the scales used.
 Looked at neuroticism, maternal love (genetic and environmental) as
well as genetic coding in twins to explain how strong bonds are with
eating patterns.
 Type of Study?
 Open label trial, both knew the study
 Retrospective; analysis of twins, bx of the past, past genetics
 Future research design?
 Maybe make the design double blind to eliminate bias, as well as
incorporating different areas or twin registries.

16. Study #3
 Genetic and Environmental Influences on
Restrained Eating Behavior
 Method: 1,196 MZ twins, 456 same sex DZ twins and 447 opposite sex
twins from the University of Washington Twin Registry. Mean age: 36,
range: 19-81 years, 90% Caucasian
 The Restraint Scale is a 10-item self-report questionnaire designed to
identify individuals with chronic dieting and weight concerns.
 phenotypic variance in the structural equation modeling was made for
additive genetic (A), common environmental (C), and unique
environmental (E) factors.
 Chosen due to the biological basis of overeating observed in restrained
eaters
 Great internal validity and rest-retest reliability.
 Asked questions about childhood similarity to assign zygosity.

17. Study #3 (cont.)
 Results:
 38% of twins never responded, 7% denied participation
 2099 met inclusion criteria
 Restraint scale score was 13. Female twins had higher scores than
males. Scores between MZ and DZ twins did not differ.
 Compelling evidence for a genetic contribution to
restrained eating. This contribution was independent of
the influence of BMI, which is both highly heritable and
associated with Restraint Scale Scores.
 Unique environmental experiences and events specific to
the individual were also important contributors.

18. Study #3 (cont.)
 Reliable?
 Not entirely, though great sample size, ages, etc.
 High reliability and validity of the scales used.
 Looked at neuroticism, beliefs on food restraint
 Controlled for BMI, good.
 Type of Study?
 Open label trial, both knew the study
 Not said explicitly. Assume it is retrospetive: looks at history of
media influences and biological influences in genetics of already seen
disordered eating in sample.
 Future research design?
 Maybe make the design double blind to eliminate response bias,
make sure DNA verification happens to validate zygosity, low
number of DZ pairs, increase next time.

19. Conclusions
 Overall, I felt that my hypothesis was not proven
entirely. For example, it is obvious that research shows
a link between eating disorders and genetics, however,
it is not clear to what extent genetics play a bigger role
over media influence.
 Further research is needed to determine the ever-
changing roles of media influences on people and how
people can adapt or be affected by predisposed eating
behaviors from the environment as a risk factor
 I believe that the study on males and female twins (#2
study) show a better realistic perspective on the
balance on genetic and environmental factors.

20. Sources
 Ferguson, C. J., Muñoz, M. E., Winegard, B., & Winegard, B.
(2012). The influence of heritability, neuroticism,
maternal warmth and media use on disordered eating
behaviors: A prospective analysis of twins. Psychiatric
Quarterly, 83(3), 353-360. doi: 10.1007/s11126-012-9205-7
 Schur, E., Noonan, C., Polivy, J., Goldberg, J., & Buchwald, D.
(2009). Genetic and environmental influences on
restrained eating behavior. International Journal Of
Eating Disorders, 42(8), 765-772. doi:10.1002/eat.20734
 Suisman, J. L., O'Connor, S. M., Sperry, S., Thompson, J. K.,
Keel, P. K., Burt, S. A., & Klump, K. L. (2012). Genetic
and environmental influences on thin‐ideal internalization.
International Journal Of Eating Disorders, 45(8),
942-948. doi:10.1002/eat.22056