Transcript Eating Behaviour

Anorexia Nervosa (AN)
Symptoms & Cause
AQA A: Specifications states: cover only one eating
disorder
“Dieting to be beautiful can go disastrously wrong”
Clinical Characteristics of Anorexia
Nervosa (AN): DSM IV tr
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Nervous loss of appetite.
Display an ‘abnormal’ attitude towards
food. (Eating Attitudes Test: E.A.T.*)
Primarily a female disorder, usually
occurring during adolescence.
There is a refusal to maintain normal
body weight.
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Individuals need to weigh less than 85% of their normal
body weight to be diagnosed as anorexic (Body Mass
Index or BMI: check online)
The distorted body image is not evident to anorexics
themselves (Body Dismorphia Disorder or BDD)
*Online: http://psychcentral.com/quizzes/eat.htm
Secondary symptoms: Anorexia causes
a general physical decline including…
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Cessation of menstruation
(amenorrhoea)
Low blood pressure
Dry and cracking skin
Constipation
Insufficient sleep
Depression and low self-esteem
Up to 20% cases of Clinical AN are fatal (1-5)
A BMI of below 18.5 is an indicator & 15 is clinical
When does it change from ‘Diet’ into an
autonomous* ‘Disorder’ (DSM IVr)?
When the BMI (Body Mass Index) is equal to or less
than 15 (below 85% expected weight by height and
frame)
However the BMI is only an indicator, it must be
accompanied by a distorted body image, an
abnormal relationship with food, a morbid fear of
gaining weight, cessation of periods (3 months) and
denial that there is a problem
*What does autonomous mean?
Why is 15% such an important figure:
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At puberty a 15% increase in body fat (‘puppy fat’)
is required to trigger the release of hormones
necessary for the development of secondary
sexual characteristics.
(Wider hips, breasts, periods, etc)
What happens if you drop below 15 BMI:
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Secondary sexual characteristic hormones
are no longer produced and the body
returns to pre-pubic child-like ‘asexuality’.
(Narrowing of hips, cessation of periods,
breasts shrink, testicular atrophy (males)
and these can be permanent!)
NB. The physiological effects of hormones are temporary
and to maintain effect continuous production is
necessary
Combined Causal Factors of AN: (AO2)
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The aetiology (cause & progression) of AN is
probably not singular, but more likely a
combination of factors including:
 Biological
 Psychological
 Familial
 Socio-cultural
Eg. The diathesis model
Genetic Predisposition + Environmental Trigger = Disorder
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AN: Biological explanations
(1) Genetic origin: Familial studies have
shown that first-degree relatives of AN
have an increased risk (MZ: 56% concordance)
of developing an eating disorder (Holland
et al. 1988) …
At age 11 there were no genetic influences on disordered eating.
However, by age 17 the heritability of disordered eating was more
than 50 percent.The recent findings implicate puberty in the
dramatic increase in genetic effects across time. (Meta-analysis from
the ‘Minnesota Twin Study’ Klump 2007)
So AO3 evaluate MZ Twin Studies and what
does it suggest (eating behaviour is partially
[50%] inherited/biologically
determined).
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(2) “Set Weight or Point” Theory: The
set-point theory argues that an
individual's metabolism (metabolic
hormones and fat cell enzymes.) will
adjust homeostatically to maintain a
weight at which the body is comfortable…
AO2 So our weight/appearance is
biologically controlled ∴ inherited/biologically
determined
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(3) Hypothalamic dysfunction:
 An “on” and “off ” command for eating
 The lateral zone function as “hunger
centre”
 The ventromedial zone operates as
“satiety centre”
AO2 So our eating (hunger> full-up) is
biologically controlled ∴
inherited/biologically determined
Biological explanations cont...
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(4) Imbalance of serotonin neurotransmitters
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Increased Serotonergic activity: Acts to suppress
appetite
There is considerable evidence that increased serotonin
activity in the brain is associated with appetite
suppression. In fact, drugs which act on serotonin
pathways in the brain are commonly used for the shortterm management of obesity
(AO2) Therefore, inherited naturally high Serotonergic
sensitivity would suppress eating and be a potential
causal factor in the development and maintenance of
AN
Link: Increase in serotonin makes you happy
Biological explanations of AN
and suppresses hunger
Biological explanations summary... (AO2)
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If anorexia can be shown to be genetic, then it must
be inherited and we have little choice (Genetic
Determinism).This then raises the question, what
physical abnormality is passed on?
Hypothalamic abnormality?
Serotonergic abnormality?
But don’t forget to be critical of twin studies:
Studies are MZ and not MZa (reared apart), therefore they
would share identical family environments (eg. shared
learning from an anorectic mother?)
This coupled with small sample size brings the strength of
evidence for genetic predisposition into question.
There must be other explanations (eg. psychological or ‘triggers’)
Some AO3 points to consider…
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In all research, the researcher is trying to
‘operationalise’ (IV’s) a factor and claim it is the
cause (DV)… is this ok?
Most research was performed in the
Industrialised West…. Is this ok?
Are twin studies reliable?
Are biological explanations the only ones
available (isolationism)?
Does the question of reductionism/determinism
arise?
Psychological explanations of anorexia nervosa
Research into cause
Psychological explanations of AN
Behaviourist Explanations (AN as a
‘Learned’ behaviour)
Classical conditioning (Learning by
association)
 Eating can be associated with anxiety since
it can make people overweight
 Losing weight ensures that the individual
reduces these feelings of anxiety ∴ Feel
fat/ugly so diet and associate happiness
with weight loss and unhappiness with
weight gain
Psychological explanations of AN
Operant conditioning (Learning as a
consequence of action)
The individual avoids food to gain a reward such
as feeling positive about themselves
In early stages – individuals can be admired or
congratulated for losing weight and looking slim
and healthy (positive regard)
Gain reward or satisfaction as a consequence of
their actions (control of their food intake)
∴ they associate their ACTION with happiness
and failure (eating something) with
unhappiness
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SLT: People imitate people they admire
(Media/Peers etc) – vicarious
reinforcement (later reward for gaining
the look)
They adjust behaviour to achieve the looks of others and gain the rewards
Consider some simple questions …..
Q) Why do you like to look good when you go
out?
Q) How do you know if you look good?
Q) What influences you when you go clothes
shopping?
Q) Why are females more anxious about visiting
a hair dresser than a dentist?
Psychological explanations of AN (AO2)
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Behaviourist Explanations – studies...
A review of 25 studies showed that a slender
beauty ideal causes body dissatisfaction and
contributes to E.D. (Groesz et al, 2001)
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The effect was most marked in girls under 19
The slim ideal becomes equated with success and
health whereas average weight or overweight
becomes synonymous with failure, and this slowly
becomes the dominant belief in society (Harrison,
2001)
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Psychological explanations of AN
Psychological explanations of AN
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Behaviourist Explanations – studies...
Women feel undue pressure on their appearance
and reported that 27% of girls felt that media
pressure them to strive to have a perfect body
(Forehand, 2001)
Increase in eating disorders in Fiji with the
introduction of American television programmes,
which emphasise a westernised idealised body
shape (Fearn, 1999)
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Psychodynamic explanations (Freud)
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Adolescents don’t want to grow up
and separate from their parents
They become fixated at the oral
stage*1; when they were completely
dependent on their parents
Anorectics lose weight, lose
secondary sexual characteristics,
become childlike again (asexual)
and return to the safety of being a
‘little girl’ again (AO2: Gender Bias)
In Freudian terms, eating and sex
are symbolically related*2
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A refusal to eat (the only control, they
feel they have) represents a refusal of
sexuality
1. Stages of
Psychosexual
development
2. Eating as manifest
representation of sex
(ego-defence)
Cognitive: Williamson et al (1993):
Distorted Body Image
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Two groups of participants
High risk AN (diagnosed)
Low risk AN (healthy + No near relatives with
AN)
Task: Put ‘stretched’ photographs of ‘self ’ back to
correct size:
Findings…..
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High Risk Group: significantly
over-estimated real size
Low Risk Group: significantly
under-estimated real size (flattered)
Conclusion:
Anorectics cognitively misrepresent
their own body image (Body
Dismorphic false belief system:
BDD).Therefore no matter how
much weight they lose, they still feel
‘fat’.
Anorectics can never reach their goal!
ED as an addiction:
Smoking…
Drinking…
Dieting…
‘Reversal Autonomy*’
(*See article: McCarthy,
2009)
So the dieting behaviour is learned,
reinforced and gains AUTONOMY and
then the dieting controls the person.
Some AO2/3 points to consider….
1. The Behaviourist Approach suggests that AN is a
‘learned’, reinforced product of ‘involuntary associations’
(classical) or as a ‘consequence of actions’ (operant)… be
critical (+/-) of this approach.
2. SLT suggests we learn ‘vicariously’ and model our
behaviour on the consequences of observation… be
critical (+/-) of this approach.
3. Psychodynamics (based on Freudian principles) suggests a
dysfunction during the ‘oral stage’ of psychosexual
development… be critical (+/-) of this approach.
In all cases consider : the approach, research methods (inc
culture), isolationism and the ‘reductionism/determinism
debate.
NB: The cognitive example supports one factor. Addiction is
an alternative way of looking at ED’s and 1 & 2 above are
nowadays combined as ‘Social Cognitive Theory’.
Assignment...
Outline symptoms of AN, then describe/evaluate two
psychological and two biological explanations.
( 25 marks)
Instructions:
The essay style answer should have an Introduction
(introduce/define). Then AO1 (9 marks) and AO2/3 (16 marks) as subheaded sections followed by a short conclusion (summary). You WILL
need to focus on AO2/3 (check ‘commentary’ and chapter summary pp
94-95 textbook: Cardwell & Flanagan).
Ideally word processed (1 to 1.5 A4 or 500/600 words).
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Psychological explanations of AN