2. Biological explanations
• Neurotransmitters
- serotonin and
dopamine
• Neurodevelopment
Pregnancy and birth
complications
Season of birth
• Evolutionary
explanations
- The reproductive
suppression
hypothesis
- The adapted to flee
hypothesis (AFFH)
3. Neurotransmitters -Serotonin
Disturbances in these levels
Higher serotonin activity activity
in women recovering from bingeeating/purging type anorexia.
Highest levels of serotonin
activity in women who showed
the most anxiety.
High levels of serotonin are
associated with jittery, anxious
feelings. In order to get rid of
these anxious feelings – the
person may stop eating.
Suggestion then, that it is the
anxiety that triggers Anorexia and
that AN is just a symptom of
getting rid of the anxiety.
4. AO2 - serotonin
• Issue in that people with AN when given
SSRI’s – makes no difference.
• Only when used with recovering AN patients
does it prevent relapse.
• Lack of food may stop the SSRI’s from
working – but then becomes successful when
food is put back into the body.
5. Dopamine
Comparison of
dopamine activity in
brains of 10 women
recovering from AN and
12 healthy women.
Overactivity in
dopamine receptors in
the basal ganglia. This
area dopamine plays a
part in interpretation of
harm and pleasure.
Pet scans
Increased activity alters the
way in which people interpret
rewards.
People with
AN find it
difficult to
associate
good
feelings with
what we
normally
derive
pleasure in –
eg food.
6. Dopamine – AO2
• Support from adolescent girls who had
higher levels of homovanillic acid (waste
product of dopamine).
• Improvement in weight levels associated with
homovanillic levels normalising
• Obese individuals – had lower than normal
levels of dopamine receptors which means
that dopamine levels are perhaps related
somehow to body weight.
7. Neurodevelopment
PREGNANCY AND BIRTH
COMPLICATIONS
Association between
premature birth and AN
Brain damage through birth
complications causing hypoxia
impairing neurodevelopment of
the baby.
If mother has eating disorder
then baby not getting the
nutrition needed.
Double disadvantage – as
mothers transmit a genetic
vulnerability to AN plus
inadequate nutrition.
8. AO2 – obstetric complications
• Support from Favaro et al (2006)
perinatal complications significantly
associated with risk of developing AN –
placental infarction (obstructed blood
supply in the placenta) and early eating
difficulties and low birth weight.
9. Season of birth
Individuals with Anorexia more
likely to be born in spring time.
People will get infections in the 2nd
trimester – time of year for getting
them.
Infections such as intrauterine
infection and high
temperature.
Willoughby et al (2005) found no
seasonality effect in the development of AN
where it is hot all year round.
10. Season of birth – AO2.
• Support by Eagles et al 2005 – AN individuals
are later in birth order compared with healthy
controls.
• The more elder siblings the child has whilst in
the womb the more likely the mother will be
exposed to common infections.
• Critical period for brain development is 2nd
trimester.
