Psychiatry SC087: Eating Disorder Flashcards
Myths about Eating disorder
- Anorexia / Bulimia were viewed as “disorder of choice” —> Devalued seriousness + Undermined treatment / recovery + Provided no guidance for families
- Genes were not a risk for eating disorder
Epidemiology of Anorexia Nervosa (AN)
Incidence:
- 4-5 / 100,000
- **F:M = 10:1
- **3rd most common illness in teenage girls
Prevalence:
- **1% School, College women
- **4-6% Models, Ballet dancers
- May be culture bound (Less in non-industrialised countries / African Americans)
- HK: 3.9% males + 6.5% females 10–21 yo
Onset:
- Usually teenage / young adulthood
- Within a few years of the menarche (12) (Few years after puberty)
Men:
- Under-reporting?
- Stigma and shame
—> Stigma of an eating disorder, fear of being femine, stigma of having a psychiatric illness atypical of one’s gender
—> Need of an all male treating environment?
- Body dissatisfaction: distinguish between muscularity and weight concern
Mortality:
- AN: ***Highest mortality rate of any psychiatric disorder
Causes of death in AN:
1. Suicide (32%) - Violent / Non-Violent
2. Anorexia (19%)
3. Cancer (11%)
Average age at death: ***34 yo
Etiology of Eating disorder
Gene-Environment interaction:
- Family history: 12x for AN, 4x for BN
Heritability estimates:
- 50-80%
- MZ:DZ = 55:24
- Unique experiences but not shared experiences
What is inherited?
- Temperamental traits
- Co-morbid anxiety, depression, OC tendencies
Biopsychosocial model:
1. Environment
2. Genes
3. Personal attributes / developmental
- Cognitive vulnerability
- Emotional regulation
- Interpersonal reaction
- Abnormal eating
Pathophysiology of Anorexia nervosa
Early phase:
Activation of Cognitive control (Active top-down systems):
- ↑ Effortful control
- ↑ Inflexibility
- ↑ Detail
—> Start to not eat / Obsessed with not eating
Inhibited bottom-up system:
- ↓ Reward from food, social etc.
- ↓ Emotions from being anxious / depressed
- ↓ Experience of bodily self
Hypothesis:
- Persistent, Maladaptive food restriction in AN is a ***habit
When restriction become habitual:
Brain systems guiding behavior shift with progression of AN:
- Early in illness, **mesolimbic reward system underlies food choice behavior
—> When illness persists, choice behavior comes to be mediated by **dorsal striatal habit system
Definition of a habit: Learned, not innate
- Initially rewarding, repeated —> overtrained
- Over time, outcome independent
Neural mechanism of habit:
- Initial learning: **Ventral fronto-striatal circuits
- Once learned: **Dorsal striatum-dorsolateral prefrontal cortex (Difficult to “de-learn” / treat)
Reward and habit circuits will predict outcome at 2 years (remission vs persistence)
- Remit at Year 2 will: Show normalization of neural activity
vs
- Still have AN at Year 2 will: Food choice associated with habit circuits activity
Anorexia Based Hyperactivity (ABA) / Semi-Starvation Induced Hyperactivity
- Restriction of food intake (1 h/d) + Unlimited access to running wheel
- Good intake declines strikingly, exercise increases stereotyped activity
—> Hyperactivity prior to food presentation
—> Food-anticipatory activity (i.e. try to exercise to avoid eating) - Overcome the basic homeostatic mechanism for survival
—> Only know model where nonhuman mammals choose self-starvation over homeostatic balance - Stronger in female and in young rats
- Early life stressors increase susceptibility to develop ABA
—> Cold temperature, early weaning
—> Amelioration by enriched environment
Vicious cycle of AN
Reduced food intake + Weight loss
—> External reinforcement + Internal reinforcement (e.g. paradoxical liveliness)
—> Positive experience
Internal reinforcement + Habit formation + Social withdrawal
—> Entrenchment
—> Loss of hunger, ED-specific cognition, Starvation-related eating behaviour, Depressed mood, Hyperactivity
Anxious, Perfectionistic, Obsessive (Predisposing factors)
—> Increased dysphoria, denial, perfectionism, obsessionality
—> Pathological eating (i.e. not eating)
—> Decreased dysphoria
—> Neurobiological change
—> Increased dysphoria, denial, perfectionism, obsessionality
Starvation on brain
Impairs brain function esp. cortical regulation (starvation will shut down ***highest function first):
- ↓ Neuroplasticity ↓ new learning (affect study)
- ↓ Executive function (unable to be flexible / shift set —> rumination; attention stuck)
- ↓ Emotional regulation (avoidance, excessive (irritable) / suppressed)
- ↓ Social cognition (isolation, socially withdrawn)
- ↓ Global connection (unable to look at bigger picture —> fragmented, overly detailed)
Temperament between AN and BN
AN:
- Harm avoidant
- Neurotic
- Obsessional
- Anxious
- Perfectionistic
- **Reward dependent
- **Low novelty seeking
- ***Extremely low self esteem
BN:
- Harm avoidant
- Neurotic
- Obsessional
- Anxious
- Perfectionist
- Low self-esteem
- **Higher novelty seeking (like to explore self-harm, taking drugs, impulsive)
- **Impulsive
- ***Affective dysregulation (vs suppressing emotions)
Predisposing factors + Precipitants for Eating disorder
Predisposing factors:
1. Biological
- Family history of ED / chemical dependency
- Mood disorder, anxiety, depression
- Traits / Temperament
- Increased BMI prior to onset
- Early onset puberty
- Cognitive lags (mature thinking lag behind girl of same age)
- Environmental
- Go fast, highly competitive academic / social environment
- Dieting culture
- High risk sports / industry
- Family history of severe dieting / exercise
- Enmeshed / Disengaged family
Precipitants:
Almost always on internal / external experience of feeling out of control
1. Onset of puberty between 11-14 yo (average young woman gains 40 pounds with a disproportionate fat ratio)
2. Major life transitions
3. Traumatic events
4. Family difficulty
5. Onset of comorbid illness e.g. anxiety / depression
6. Weight loss through dieting / increased exercise
Risk factors for AN
- Family
- Family history of depression
- Family history of alcoholism
- Family conflict / trauma parental deprivation
- Sexual abuse
- Physical abuse
- Emotional abuse - Society
- Social pressures on women
- Emphasis on thinness
- Role confusion
- Mixed messages for women - Personal
- Poor problem-solving skills
- Low self-esteem
- Low mood
- Depression
- High anxiety
- Nervousness
- Perfectionism
- Self-criticism
- Impulsivity
- Fears about sexuality
- Relationship problems
- Weight loss from physical illness
Process of AN
- Initial dieting + weight loss
- Beginning of AN
- secrecy + lying about dieting
- continued weight loss
- hunger - AN takes over (AN mentality controlling the patient)
- extreme fear of weight gain
- total preoccupation with food + weight
- loss of hunger
- harder to lose weight (∵ metabolic rate slower) - Symptoms of starvation
- cold intolerance
- electrolyte disturbances
- low blood sugar
- dizziness
- tiredness, lack of energy
- lowered metabolic rate
- lowered (or irregular) heart rate
- muscle loss
- moodiness, irritability
- dry pasty skin
- headaches
- visual problems
- poor sleep
- water retention
- gastrointestinal problems
- irregular or absent periods
Classification of Eating disorders
- Anorexia nervosa (more associated with **OCD spectrum, **Autistic spectrum)
- Restricting
- Binge-purging - Bulimia nervosa (more associated with **Affective disorder, **Bipolar spectrum, **Addiction spectrum, **ADHD)
- Binge-purging
- Non-purging - Binge eating disorder (BEN)
- Others
- EDNOS (heterogeneous, 50-70%)
- ***Significant overlap
- Operationally defined in ICD-10, DSM-IV
***ICD-10, DSM-IV, DSM-5 criteria for AN
ICD 10
1. Significant weight loss [BMI ***<17.5 kg/m2] or 15% below; or failure to gain weight or growth
- Self induced weight loss by:
- **Avoiding fattening foods
- **Vomiting
- **Purging
- **Excessive exercise
- ***Diuretics / stimulants - ***Body Image distortion
- Dread of fatness, a persistent overvalued idea - Abnormalities of hypothalamic-pituitary-gonadal axis
- Amenorrhoea
- ↓ Libido, male potency, T3
- ↑ GH, cortisol - ↑ Puberty delayed If onset prepubertal
DSM-IV:
A. Refusal to maintain body weight more than minimal normal weight for age and height
B. Intense fear of fatness
C. Body image disturbance
D. Amenorrhoea in post menarche females (subtypes restricting / binge eating-purging)
DSM-5:
A. **Restriction of energy intake, leading to significantly **low body weight in context of age, sex, developmental trajectory, and physical health (less than minimally normal / expected)
B. **Intense fear of fatness
C. **Body image disturbance
- No longer includes the word “refusal” (∵ implies intention on the part of patient)
- Criterion D requiring amenorrhea, or the absence of at least three menstrual cycles, will be deleted (∵ cannot be applied to males, pre-menarchal females, females taking oral contraceptives and post-menopausal females)
BMI measure of risk
Summary Measure of Risk
Maudsley Body-Mass Index Table:
20-25: Normal weight range
- 5-20: Underweight
- Irregular or absent menstruation
- Ovulation failure
15-17.5: AN
- Amenorrhoea
- Loss of substance from all body organs and structure
- 5-15: Severe AN
- All organ systems compromised: bone, heart, muscle, brain
12-13.5: Critical AN
- Inpatient treatment recommended
- Organs begin to fail: muscle, bone marrow, heart
<12: Life-threatening AN
Also the lower the BMI —> change in cognition (more % of time brain preoccupied by not eating, exercise)
***Medical complications of AN
- Cardiac
- **bradycardia
- **hypotension (hypothermia)
- ***prolonged QTc
- arrhythmia
- edema - Gastrointestinal
- decrease gastric emptying
- **intestinal hypomotility
- **deranged LFT - Metabolic and endocrine
- **low estrogen, FH, LSH
- **low T4
- **increased cortisol, osteoporosis
- fluids and electrolytes: low kidney filtration, edema
- **hypercholesterolaemia (SpC Psychi PP) - CNS
- ***decreased brain mass
- decreased mood, concentration, IQ, sleep
- increased obsessionality, anxiety, ritualized behaviour - Dermatological
- dry skin
- brittle nails
- thin hair
- ***lanugo hair - Haematological
- ***pancytopenia
