What Is Anorexia Nervosa?

Anorexia nervosa (AN) is an eating disorder where a person restricts their energy intake with the intent to change their body shape or weight. This eating disorder is similar to Avoidant Restrictive Food Intake Disorder (ARFID), in that the person severely limits their food intake. However, in the case of AN, food restrictions are directly linked to disturbances in how a person experiences their body; the person places extreme value on their body weight and shape when evaluating their self-worth. To avoid gaining weight, individuals with AN may engage in extreme behaviors such as intense exercise, binging, purging or restricting their eating behaviors dramatically.

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How common are eating disorders?

The lifetime prevalence of eating disorders among adolescents in the U.S. is 3.8 percent for women and 1.5 percent for men, according to the National Institute of Mental Health. Among adults in the U.S., the overall prevalence of binge-eating disorder is 1.2 percent, the overall prevalence of anorexia is 0.6 percent, and the overall prevalence of bulimia is 0.3 percent. 

Studies that slightly expand the diagnostic criteria find higher estimates of eating disorders, such as 5 percent of adolescent girls or nearly 8 percent of individuals overall. Eating disorders can occur at any time, but they typically develop in one’s adolescence or early twenties. 

Has the prevalence of eating disorders increased over time? 

Although eating disorders have existed throughout human history, they seem to be growing more widespread today. One large review study found that 3.5 percent of people suffered from an eating disorder in the years 2000 to 2006, yet nearly 8 percent suffered from one in the years 2013 to 2018. 

A particularly unsettling trend is that anorexia may be increasing among children. One recent study found that anorexia had increased among 8- to 12-year-olds in the past decade, which is consistent with other research showing that the age of onset for anorexia may be decreasing. 

Diagnosis of Anorexia

According to the Diagnostic and Statistical Manual Version 5 (DSM-5), anorexia nervosa can be diagnosed when: 

  • The person restricts their energy intake to less than what is required. This has resulted in body weight that is significantly less than the minimal expected based on age, developmental norms, sex and physical health. 
  • Persistent behaviors that interfere with weight gain or the extreme fear of gaining weight. 
  • The person’s self-worth is influenced by their body’s weight or shape and this disturbs them or they fail to acknowledge the seriousness of their low weight. 

The DSM-5 also makes provisions to specify the type of AN as: 

  • Restricting type – the person has not regularly engaged in binge-eating or purging. 
  • Binge-eating/purging type – the person has regularly engaged in binge-eating or purging in the last 3 months. 
  • Partial remission – the person meets all the above criteria, but the condition of low body weight has not been met for a sustained length of time. However, the person still meets the criteria of: 
  •  An intense fear of gaining weight or being obese or engaging in behaviors that interfere with weight gain. 
  • Disturbed by body weight and shape 
  • Full remission – All criteria met previously, but none met for a prolonged period of time 

It is also extremely important to consider whether someone might meet the criteria for atypical anorexia nervosa. This eating disorder falls under a different DSM-5 category of other specified feeding or eating disorder (OSFED). This category is for people who might not meet all of the criteria of anorexia or bulimia, but still have a serious eating disorder. Atypical anorexia is often overlooked, because the person appears to be a healthy weight, however, they meet all the other criteria for a diagnosis of anorexia. Their disorder is as serious and is also potentially life-threatening. 

Screening Tools for Anorexia

Screening tools can be used to see if a person has any of the risks and/or behaviors associated with anorexia.  These tests can be very helpful in motivating a person to seek treatment and in supporting a diagnosis. Each person has a unique relationship with eating and their body. Screening tools can help health professionals to understand the complexities of this relationship, which can inform treatment and help the person in their recovery journey. Overall, screening tools for EDs will investigate: 

  • The person’s relationship with food 
  • How the person experiences their body and the relationship they have with it 
  • How much the person’s feeling of self-worth is influenced by their body weight and shape 
  • Extreme behaviors – such as binging, purging or excessive exercise 
  • Loss of control over eating 
  • Behaviors the person may use to compensate for their eating  patterns 

There are many screening tools to help clinicians in making a diagnosis of AN.

Examples of screening tools for anorexia include: 

  • Medical Tests Such as lab tests for nutrients, minerals, blood count and kidney, liver and thyroid function.
  • The Eating Pathology Symptoms Inventory (EPSI) A self-report test that investigates 8 features of disordered eating, such as body dissatisfaction, restriction and negative attitudes towards obesity
  • The SCOFF questionnaire A self-report test that asks 5 questions, each of which represents a letter in the SCOFF acronym. If the person answers “yes/true” for 2 or more of the questions, they are likely to have anorexia or bulimia.
  • The Eating Disorder Examination Questionnaire (EDE-Q) This test is often considered the “gold standard” screening tool for EDs. It is a 28-question test that investigates restraint and the concern for eating, weight and body shape that the person has. There is also a shortened 8-question version of this test known as the EDE-Q8.
Dual Diagnosis and Anorexia

Dual diagnosis is when someone has two or more mental health conditions at the same time. It is not uncommon for people diagnosed with anorexia to also meet the diagnostic criteria for: 

Anxiety disorders


Obsessive compulsive disorder (OCD)

Post-traumatic stress disorder (PTSD)

Substance use disorders 

It is extremely important to find a treatment center, such as Koru Spring, that has the expertise and training to treat both conditions concurrently. A dual diagnosis helps health professionals to understand and investigate how one mental health condition might exacerbate the other. Treatment of anorexia nervosa requires a holistic approach and this includes treating all mental health conditions that the person is experiencing.

Causes and Risk Factors

Eating disorders are complex and can affect a wide range of people. While no one thing causes an eating disorder, a complex mix of biological, psychological and social risk factors can play a role. It is important to remember that no one chooses to develop an eating disorder and not to blame the individual.  

Some of the risk factors that can play a role in the formation of anorexia and other eating disorders include: 

Biological risk factors:

  • Having a parent or sibling with an eating disorder 
  • Having a close relative who has a mental disorder (such as anxiety, depression or substance abuse disorder) 
  • Excessive dieting or other behaviors related to weight-loss in their past (this is especially linked to the development of binge eating) 
  • Illness, growth spurts, dieting and intense exercise or athletic training can all lead to more energy being used than the person takes in and can be part of developing AN 
  • Having Type I diabetes requires that a person injects insulin to absorb energy from food. Missing injections can lead to the development of diabulimia or other eating disorders (such as AN). 

Psychological and emotional risk factors:

  • Perfectionism (especially self-oriented perfectionism, where the person has unrealistic expectations of themselves and sets unobtainable or unsustainable standards) 
  • Having a disturbed or distorted body image. Negative body image is related to feelings of shame, anxiety and extreme self-consciousness about the individual’s body shape and size. It is related to depression, anxiety and the development of eating disorders. 
  • Having an anxiety disorder (about two thirds of people diagnosed with anorexia also shows signs of anxiety disorders). 
  • Being inflexible about behaviors, such as feeling that there is only one “correct” way to do something, is something that many people with AN report experiencing from childhood. 

Social risk factors:

  • Societal ideals of body weight and shape leads to weight stigma. In all forms of media and social discourse, there is a pervasive message that being a certain weight or shape is the only body type that is “correct”. These ideals vary by culture and what the current fashion is, but thinner is generally “better”. Internalizing this appearance ideal can lead to body image dissatisfaction and may lead to the development of an eating disorder to try to attain the idealized body. 
  • Weight-shaming, bullying and teasing was reported by around 65% of those diagnosed with an ED to have directly influenced the development of their eating disorder. 
  • Accessibility of Westernized media by minority ethnic groups worldwide may interact with stress, acculturation and body image to influence the development of eating disorders in these, often vulnerable, groups. 
  • Social isolation (be it circumstantial or due to mental illness) and feeling alone are often reported by those diagnosed with anorexia. 
Signs and Symptoms

The signs and symptoms of many eating disorders overlap significantly and all severely impact the mind and body. The physical signs and symptoms of anorexia are related to negative energy intake and starvation. Psychological signs and symptoms are related to negative body image and behaviors that may be used to compensate for the physical symptoms or hide behaviors or physical signs that others have noticed and expressed concerns over. Signs and symptoms for anorexia nervosa can include: 

Physical signs and symptoms:

  • Dramatic loss of weight or lower than expected weight gains for healthy development 
  • Looking very thin 
  • Blood counts that are abnormal and concerning 
  • Tiredness, dizziness or fainting 
  • Insomnia 
  • Dry, brittle hair and nails 
  • Dry, yellowish skin and bluish discoloration of fingertips or toes due to poor circulation 
  • Thinning hair  
  • Constipation, abdominal pain, stomach cramps and other gastrointestinal symptoms   
  • Menstrual cycle irregularities or no menstruation at all 
  • Hormonal imbalances 
  • Fine hair grows on the body (lanugo) 
  • Heart problems, such as irregular heart rhythms and low blood pressure 
  • Weak bones 
  • Feeling cold all the time 
  • Dehydration 
  • Swollen legs, ankles or arms, which could be due to problems with the heart, dehydration, hormone imbalances or electrolyte imbalances 
  • Callused knuckles and tooth decay due to purging (induced vomiting) 

Behavioral signs and symptoms:

  • Dramatic restriction on food intake (severe dieting or fasting) 
  • Exercising excessively to create a negative energy balance between food intake and energy used 
  • Bingeing and purging (which may include self-induced vomiting or the use of laxatives, enemas, diet aids or herbal products to remove food from the body)  
  • Refusing to eat or eating only “safe” foods (usually those with low fat or low calorie content) 
  • Skipping meals, denial of hunger or making excuses for not eating 
  • Adopting rituals around eating or food that are extremely rigid (such as chewing food and then spitting it out) 
  • Compensating behaviors for always feeling cold (such as dressing in layers) 
  • Frequently and repeatedly measuring or weighing their body or looking in the mirror to check body shape 
  • Engaging in behaviors that relate to a preoccupation with food such as cooking elaborate meals for others, but not eating them 

Psychological and emotional signs and symptoms:

  • Preoccupation or intrusive thoughts about food  
  • Anxiety about eating in public 
  • Lying about how much or how frequently they eat 
  • Intense fear of gaining weight  
  • Extreme criticism of their weight or body shape 
  • Flat mood (lack of emotion) 
  • Isolating themselves from social activities 
  • Isolation from support networks and loved ones 
  • Irritability 
  • Insomnia  
  • Always feeling fatigued 
  • Reduced interest in sex 

Anorexia can be life-threatening and can severely limit how a person functions and interacts with the world. Not everyone with anorexia will have all of these signs and symptoms, but if you or a loved one experience some of these and feel that they would like to speak to someone about seeking help, please contact the Koru Spring team. 

Treatment Options

Treatment for anorexia and other eating disorders requires a holistic approach to healing- where many medical and clinical professionals work as a team to create a treatment plan that is tailored to the individual. The treatment for anorexia will usually include: 

  • Personalized meal plans by dieticians 
  • Medical care – potentially including prescription drugs to help with appetite, anxiety, depression and nutrition 
  • Psychological therapy to help the person understand their emotional triggers and challenges and to help them to overcome psychological obstacles they have surrounding food intake
  • Family therapy to help support the patient’s recovery

Nutritional and medical treatment

There are important nutritional goals in treating anorexia: 

  • Restoring electrolyte balance (especially potassium, magnesium and phosphorus) 
  • Restoring weight and maintaining it at a healthy level for the individual 
  • Relearning to understand the signals for hunger, fullness and satiety 
  • Developing a neutral feeling towards food and eating 

Medical care can be complex for anorexia nervosa and treatments need to be carefully monitored. A key part of treating anorexia is reintroducing energy and nutrients into the person’s body, eventually leading to the restoration of a healthy weight for the individual. A goal, such as 1-2 pounds of weight gain per week, is usually set by the team of health professionals based on a detailed medical history of the person.  They will start the refeeding process and the individual will have their food intake carefully monitored, along with their electrolyte balance, organ function and any other medical issues that they present with. 

If the malnourished person receives too many nutrients too quickly they can develop Refeeding Syndrome (RS). This manifests in water-based electrolyte imbalances that can be extremely dangerous and result in cardiac failure. Electrolytes will be redistributed to create new cells and muscle tissue when there is a positive energy balance. This can result in too few electrolytes being available to make enough energy to power the heart and results in heart failure. 

Psychological treatment

Psychological treatment for anorexia focuses on helping the person to gain insight about their thoughts and feelings so that they can develop a healthy relationship with food and their body. They also involve developing healthy coping mechanisms to assist the person in maintaining their recovery. 

Psychological treatments may involve individual, experiential, group and family therapy. Each person will have a combination of these that works best to progress their recovery journey. Some therapeutic approaches that have been found to be effective in the treatment of anorexia include: 

Cognitive Behavioral Therapy (CBT) helps the person to understand the connection between their thoughts, feelings and behaviors. Focuses for treating anorexia may include challenging or reframing thoughts and feelings around body image and self-worth and developing healthier coping behaviors.  

Dialectical Behavior Therapy (DBT) is based on CBT, but adds mindfulness practices and other emotional coping/management techniques. It includes skill building to: 

  • Create and maintain mindfulness practices 
  • Develop better interpersonal relationships and communication skills 
  • Manage and understand your emotions 
  • Cope with stressors 

Family-based Treatment (FBT) may also be extremely beneficial. As with all eating disorders and other mental illnesses, a good support system is crucial for recovery. Eating disorders affect more than the individual; they affect their loved ones too.