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Causes of Anorexia Nervosa
Transcript of Causes of Anorexia Nervosa
Dizziness or fainting
Bluish discoloration of the fingers
Hair that thins, breaks, or falls out
Soft, downy hair covering the body
Absence of menstruation in girls Constipation
Intolerance of cold
Irregular heart rhythms
Low blood pressure
Swelling of arms or legs Emotional and Behavioral Refusal to eat
Denial of hunger
Fear of gaining weight
Flat mood (lack of emotion)
Lying about how much food has been eaten Social withdrawal
Preoccupation with food
Reduced interest in sex
Possible use of laxatives, diet aids, or herbal products Prevalence It is estimated that up to 24 million Americans have an eating disorder.
The lifetime prevalence of Anorexia Nervosa is 0.6%
This is nearly 2 million Americans suffering from anorexia! Epidemiology Rates of minorities with eating disorders are similar to those of white women.
95% of those with eating disorders are between the ages of 12 and 25.
The condition largely affects young adolescent women, with girls between 15 and 19 making up 40% of all cases.
The average age of onset for AN is 19.
Female athletes in aesthetic sports such as gymnastics, dance, and figure skating have been found to be at the highest risk for eating disorders.
Approximately 75% of people with anorexia are female.
AN is more prevalent in the upper social classes and is declared to be rare in less developed countries.
Eating disorders have the highest mortality rate of any mental illness.
Anorexia Nervosa has a mortality rate of 4%.
20% of people suffering from anorexia will die prematurely from complications relating to their eating disorder, including suicide and heart problems.
Only 30-40% of patients will ever fully recover. Diagnosis Diagnostic Criteria for Anorexia Nervosa from the DSM IV-TR Refusal to maintain body weight at or above a minimally normal weight for age and height. For example, weight loss leading to maintenance of body weight less than 85% of that expected or failure to make expected weight gain during period of growth, leading to body weight less than 85% of that expected.
Intense fear of gaining weight or becoming fat, even though patient is underweight.
Disturbance in the way one's body weight or shape is experienced, undue influence of body weight or shape on self evaluation, or denial of the seriousness of the current low body weight.
In postmenarcheal females, amenorrhea, i.e., the absence of at least 3 consecutive menstrual cycles. A woman having periods only while on hormone medication still qualifies as having amenorrhea. Risk Factors Being female
Being an adolescent or young adult
A period of diet restriction/weight changes
Trauma or emotional stress
A new school, home, or job, a relationship breakup, or the death or illness of a loved one can trigger the onset of anorexia
Certain sports, work, and artistic activities
Athletes, actors and TV personalities, dancers, and models are at higher risk of anorexia
Pressure from the media and society Complications Anemia
Heart problems, abnormal heart rhythms, and heart failure
Bone loss, osteoporosis
In females, absence of a period
In males, decreased testosterone
Gastrointestinal problems, such as constipation, bloating, and nausea
Electrolyte abnormalities, such as low blood potassium and sodium chloride
Death Note: If a person with anorexia becomes severely malnourished, organs can be damaged to the point that even when the anorexia has been controlled, the damage is not fully reversible. Comorbidity Anorexia Nervosa often occurs in patients with other diagnosed mental conditions. These disorders include:
Major Depressive Disorder
Anxiety disorders, especially
Obsessive-Compulsive Disorder (about 40% of AN patients have OCD)
Social Anxiety Disorder (about 20% of AN patients have Social Anxiety Disorder)
Many AN patients also engage in self-harm behaviors. Treatment
Abnormalities in serotonin, dopamine, and orexin levels in the hypothalamus are three major factors in the predisposition for Anorexia Nervosa. Mice that are exposed to high levels of dopamine and serotonin, low levels of orexin, environmental stress, and a period of low caloric intake will be much more likely to develop anorexic behaviors than control mice, and the more factors different mice are exposed to, the more likely they will be to develop anorexic behaviors. Psychotherapy- focuses on the underlying emotional and cognitive issues that result in the disordered eating
Cognitive Behavioral Therapy- focuses on identifying and altering dysfunctional attitudes and beliefs that trigger/perpetuate the disordered eating. Keeps a specific goal in mind
Family Therapy- helps the family understand how to help their child and helps the patient understand how their illness affects the family
Medications- While there are no specific medications for AN, some patients are helped by
Antidepressants- many patients with AN also have depression, and these symptoms can be relieved by antidepressants
Estrogen- some girls are put on estrogen to help keep their bones from becoming too weak Our Hypothesis Why Serotonin? Plays a role in learning, mood and sleep
Affects anxiety and appetite
Studies show a correlation between Anorexia Nervosa and elevated serotonin levels
Anorexia symptoms include anxiety and obsessive behaviors (known to be a direct cause of elevated serotonin)
Starvation by AN patients is suspected to be an attempt to lower serotonin levels to improve mood and reduce anxiety Residential Treatment Facilities Residential treatment facilities are inpatient programs which can help a patient with AN focus on improving their health. These programs include many specialists- psychologists, nutritionists, medical doctors, and often relaxation specialists- who work together to provide individualized treatment for each patient. The residential atmosphere can help a patient focus exclusively on their health and speed recovery. Insurance will often cover these programs for a limited amount of time. Hospitalization In extreme cases, if a patient becomes severely emaciated or malnourished, hospitalization becomes necessary. Hospitalization focuses foremost on raising body weight, and if a patient is resistant to eating, feeding tubes may be used. Hospitals also provide psychotherapy to their patients. As soon as it is considered safe to do so, patients are moved to outpatient therapy. Why Dopamine? Neurotransmitter found in hypothalamus
Major role in motivation, reward, mood, cognition, learning and sleep
Mesolimbic dopaminergic pathway is relevant in AN because it plays an important role in fear, addiction and pleasure
The nucleus accumbens (part of the mesolimbic pathway) is part of basal ganglia, which is a brain region found to have overactive dopamine receptors in AN patients
Dopamine is a "reward" released in response to food
Increased dopamine yields pleasure in healthy people
Not the case with AN sufferers, as their levels of dopamine are already so high that the dopamine released after eating causes discomfort and extreme anxiety (studies have shown that excessive dopamine causes hypersensitivity and paranoia)
These high levels of dopamine remain in recovered patients, indicating a biological condition that could predispose individuals to AN
It has been suggested that AN patients starve themselves in order to avoid discomfort Effectiveness Unfortunately, though treatments can be very helpful, many AN patients do not respond well. Relapse is a severe issue in eating disorders, and only 30-40% of patients will ever fully recover from the disease.
Better treatments are necessary, and in order to find these treatments, we must begin to figure out the causes behind Anorexia Nervosa. This is what our research is focused on. Neurotransmitter and hormone that regulates arousal, wakefulness, and appetite.
Only produced in hypothalamus, but receptors for it are found throughout the brain and spinal cord
Increases appetite in rats, and has been shown to have a correlation with BMI in humans
It has been suggested that patients with AN have abnormally low levels of orexin, causing them to have a decreased appetite
There has also been some research on the link between levels of orexin and social interaction in mice. Though tentative, this research introduced a possible connection between environmental and biological factors that cause anorexia.
Since this relationship is a recent idea and has not been thoroughly researched yet, we want to explore the effects of orexin on AN. Why Orexin? Our Experiment Goal: Environmental Factors AN patients have often experienced trauma or severe emotional stress before developing the disease
AN is also linked to chronic stress
Onset of anorexia is often triggered by dieting periods or decreased food intake due to injury or illness
These periods may seem harmless at first, but the disorder can develop quickly when the individual is biologically predisposed to it We are testing multiple factors that have been implicated as possible causes or triggers of Anorexia Nervosa. These include stress, dieting, high dopamine, high serotonin, and low orexin. To better understand causes and triggers of AN, and how different combinations of factors affects the onset of Anorexia Nervosa. Important Brain Structures Involved in Anorexia Nervosa Structure within the brain that plays a role in the autonomic functions of the peripheral nervous system
There is a strong correlation between certain functions of the hypothalamus & main themes of AN such as control of food intake
The hypothalamus directly communicates with the nucleus accumbens (group of neurons associated with reward and pleasure)
Dopamine, serotonin & orexin are all found in the hypothalamus To do this, we are using mouse models. We can control the levels of neurotransmitters in these mice, as well as environmental factors, and observe the effects of these changes on behavior. The Role of the Hypothalamus
Transfers dopamine from ventral tegmental area to the nucleus accumbens
Considerably associated with:
Reward and pleasure
Motivation and emotional response
Permits for the establishment of behaviors or rituals by connecting habits with a feeling of enjoyment The Mesolimbic Pathway Experimental Design Adolescent lab mice (6-9 weeks old)
Starting weight between 25-35 grams
During 6th week of life:
Begin neurotransmitter treatment
Begin stressing mice in groups 2 & 3
Begin diet restriction in group 3
In 7th week of life, begin recording data
Continue neurotransmitter treatment
Continue stressing groups 2 & 3
Return normal amounts of food to group 3
For 3 weeks, monitor behavior, food intake, and test for neurotransmitter levels Group 1 Group 2 Group 3 Details Neurotransmitter Treatment To manipulate levels of neurotransmitters in the brain, we will:
Serotonin- micro-inject the hypothalamus with serotonin.
Dopamine- micro-inject dopamine into the basal ganglia
Orexin- to inhibit orexin, we will micro-inject the hypothalamus with norepinephrine. Chronic Stress Treatment Restricted Diet Typical lab mice eat about 3 to 5 grams of food per day. For mice with regular eating intake, we will provide 7 grams of food each day.
When we restrict the diet of group 3 for a week, we will only provide 2 grams of food per day. The next week, we will increase the provided food back to 7 grams. These will simulate abnormalities in the brains of AN patients. The Basal Ganglia Group of nuclei located on the sides of the thalamus
Linked to several functions such as procedural learning having to do with habits like cognitive & emotional functions
Supplies the striatum with dopamine
Several studies show overactive dopamine receptors in the basal ganglia of AN patients Evaluation Behavioral Biological Record grams of food eaten per day
Note any abnormal behavior (for example, unusual sleep habits, activity levels, etc.) Test blood for serotonin and dopamine levels every 7 days, starting from beginning of neurotransmitter treatment.
Test CSF for orexin levels every 7 days.
Record weight of mice each day. Results Expected Mice in group three with all three neurotransmitters adjusted would have the highest rate of anorexia
The more factors a mouse experiences, the more likely it is to exhibit anorexic behaviors. Note: Each mouse in this drawing represents one subgroup. Each subgroup is made up of 5 mice. Unexpected This would confirm a role of these hormones and environmental factors in the acquisition of anorexia.
We would also be able to see which factors have the most effect. Whichever factors were not used on this group of mice would probably not be a contributor to the onset of AN. Mice do not respond to any of the environmental conditions- maintain the same feeding behaviors as control mice. This would imply that we are missing a major factor in the onset of anorexia and the conditions we imposed are not significant factors by themselves. Mice will be shocked approximately ten times per day, at random
Moderately stressful environment for mice Conclusion Sets of 5 mice were used to test various combinations of biological and environmental factors implicated in anorexia.
Behavior, weight, and food consumption were carefully observed to determine anorexic behaviors in tested mice.
This research can show us how much these factors actually affect the onset of AN, and what combinations are most potent. Future Research Could incorporate more factors suspected in causation of AN
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