Anorexia nervosa

Symptoms and key features

Beyond the three DSM-5-TR criteria, the illness typically brings a recognizable cluster of experiences and behaviors:

• Rigid rules about food, calories, timing, foods that are "allowed" or "safe"
• Ritualized eating: cutting into small pieces, rearranging on the plate, eating slowly, avoiding eating in front of others
• Exercise that feels compulsory, that has to be completed even when the person is unwell or injured
• Preoccupation with food (recipes, cooking for others, watching food content) that is not matched by eating
• Body checking (repeated weighing, measuring, pinching, mirror checking)
• Loss of menstrual periods in people who menstruate (though this was removed as a required criterion)
• Cold intolerance
• Lanugo (fine downy hair on face, arms, back)
• Thinning scalp hair
• Brittle nails
• Dry skin, particularly on hands and feet
• Dizziness and syncope
• Low heart rate (bradycardia), often below 50
• Low blood pressure and orthostatic changes
• Low body temperature
• Rigidity and difficulty with cognitive flexibility
• Withdrawal from social eating and social life more broadly
• Black-and-white thinking about food and body

Suicidal thoughts and self-harm are more common than in the general population, and are taken seriously in every treatment plan.

What research says

Prevalence. Point prevalence estimates in developed countries run around 0.3 to 1 percent for adolescent and adult women, with lifetime prevalence in some studies closer to 2 to 4 percent using broader definitions. Recent studies with atypical anorexia included find higher overall rates. The illness is most often diagnosed in adolescence and young adulthood, though it can begin earlier and can persist or first present in mid-life. Men account for about 25 percent of clinical cases and higher percentages in some atypical presentations.

Mortality. Anorexia has among the highest mortality of any psychiatric condition. Arcelus et al. (2011) meta-analysis of 36 studies estimated a standardized mortality ratio of 5.86 for anorexia, nearly six times the age- and sex-matched mortality of controls. Suicide accounts for about 20 percent of anorexia deaths; the remainder are from medical complications of starvation. That number is not a reason for shame; it's a reason for early treatment.

Course. Course is variable. About 50 percent of patients achieve full recovery, 30 percent achieve partial recovery, and 20 percent have a chronic course. Recovery, when it happens, typically takes 4 to 6 years from diagnosis. Adolescent-onset cases treated early have better prognosis than adult-onset chronic cases.

Evidence-based treatment. Treatment differs by age.

In adolescents, family-based treatment (FBT, also called the Maudsley approach) has the strongest evidence for restoring weight and reducing illness. Lock and Le Grange developed the manualized version; multiple RCTs support it. FBT empowers parents to take charge of refeeding during Phase 1, with the child gradually taking back control over eating in Phases 2 and 3.

In adults, several treatments perform similarly in trials:

• Enhanced cognitive behavioral therapy for eating disorders (CBT-E) developed by Christopher Fairburn at Oxford. Manualized outpatient treatment, typically 40 sessions over 40 weeks for underweight patients.
• Specialist supportive clinical management (SSCM) developed for anorexia specifically. Structured outpatient therapy focused on the physical, psychological, and social aspects of the illness.
• Maudsley model of anorexia treatment for adults (MANTRA) developed by Ulrike Schmidt and colleagues. Uses cognitive-interpersonal maintenance model.

No single approach dominates in adults. Getting into any evidence-based treatment and staying with it matters more than picking the "right" one.

Medications. Medications don't treat anorexia directly. SSRIs are commonly used for co-occurring depression, anxiety, and OCD, and are often more effective once weight is restored (the malnourished brain doesn't respond well to antidepressants). Olanzapine has some evidence in RCTs (Attia et al. 2019 AJP) for improving weight gain and reducing distress in some adults with anorexia, though it isn't a first-line treatment and side effects require monitoring.

Nutritional rehabilitation and medical monitoring are foundational. Refeeding after prolonged restriction has specific medical risks that require monitoring and gradual increase in intake under supervision.

What anorexia nervosa is

The DSM-5-TR defines anorexia nervosa by three features:

Criterion A. Restriction of energy intake relative to requirements, leading to a significantly low body weight in the context of age, sex, developmental trajectory, and physical health. Significantly low means less than minimally normal for adults, or for children and adolescents, less than minimally expected.

Criterion B. Intense fear of gaining weight or becoming fat, or persistent behavior that interferes with weight gain, even at a currently low weight.

Criterion C. Disturbance in the way body weight or shape is experienced, an undue influence of body weight or shape on self-evaluation, or persistent lack of recognition of the seriousness of the current low body weight.

Two subtypes are described:

• Restricting type. Weight loss during the last three months has been accomplished primarily through dieting, fasting, or excessive exercise.
• Binge-eating and purging type. The person has engaged in recurrent binge eating or purging behavior (self-induced vomiting or misuse of laxatives, diuretics, or enemas) during that period.

Severity is graded by body mass index in adults or BMI percentile in children and adolescents:

• Mild: BMI ≥ 17
• Moderate: BMI 16-16.99
• Severe: BMI 15-15.99
• Extreme: BMI < 15

That grading matters clinically because it guides monitoring and level of care, but it's not the whole picture. Two people with the same BMI can be at very different medical risk depending on how fast they lost weight, what they have been eating, and how their vital signs are behaving.

The ICD-11 uses parallel criteria under 6B80 Anorexia Nervosa, with slightly broader wording that captures presentations at borderline BMI. The DSM-5 revision (2013) removed the amenorrhea criterion that had been in DSM-IV, recognizing that many people with the condition (including men, prepubertal children, and people on hormonal contraceptives) don't have that specific feature but otherwise clearly meet criteria.

Atypical anorexia nervosa is a related condition (DSM-5-TR OSFED subtype) with all the same features except that weight is within or above the normal range despite significant weight loss. Growing recognition of atypical anorexia has changed clinical practice; the medical risks can be similar to typical anorexia, and treatment approaches are similar.

What it feels like

The most useful thing to know if you haven't been close to it is that anorexia rarely feels the way outsiders assume. It doesn't feel like being on a strict diet. It doesn't feel like being especially disciplined or admirable. From the inside, especially early on, it can feel like relief. Restriction quiets a mind that was noisy with worry. Numbers become something that can be counted, controlled, and gotten right. The body becomes a project that can be worked on.

Over time, that relief narrows. The rules multiply. The list of safe foods shrinks. Exercise stops being a choice and becomes a requirement. Time and attention that used to go to friends, school, work, or hobbies fold into food and body. What started as a way to feel less anxious becomes a full-time job.

Underneath, the physical and cognitive effects of starvation begin to shape the mind that is trying to make decisions about food. Ability to think flexibly narrows. Mood drops. Anxiety climbs. Social withdrawal deepens. This isn't personality; it's biology. The Minnesota Starvation Experiment (Keys 1950), a landmark study in which previously healthy conscientious objectors ate too little for many months, showed that even previously well-adjusted people developed obsessive food thoughts, ritualized eating, depression, and social withdrawal from starvation alone. The illness borrows and amplifies those effects.

The fear of gaining weight is usually not a fear of a specific number. It's a fear of losing the felt control that restriction has been providing. That's part of why insight can look strange from the outside. A person who is medically at real risk can still feel calmly certain that they are fine, or that things need to keep going as they are, at least a little longer.

Body image disturbance in anorexia is not a simple misperception of size. It's a complex distortion in which the person may know objectively that they are underweight but experience their body as too large, or focus intensely on specific body parts that feel unacceptable. Trying to talk the person out of the perception through logical argument typically doesn't work.

Medical complications

Anorexia has substantial medical complications, most of them reversible with adequate refeeding but some with long-term consequences:

Cardiovascular. Bradycardia (heart rate below 50, sometimes below 40 in severe cases). Prolonged QT interval on ECG. Reduced left ventricular mass. Mitral valve prolapse. Peripheral edema during refeeding. Sudden cardiac death is a major cause of mortality.

Endocrine. Amenorrhea. Low estrogen or testosterone. Impaired thyroid function (usually reversible). Elevated cortisol. Impaired growth hormone response. Low reproductive hormones.

Bone. Osteopenia and osteoporosis develop rapidly, often within one year of significant underweight. Bone loss may not fully reverse even after weight restoration, particularly if the illness occurred during adolescence when bone is still accruing.

Gastrointestinal. Delayed gastric emptying (produces bloating and early fullness during refeeding). Constipation. Elevated liver enzymes. Superior mesenteric artery syndrome in severe cases. Refeeding pancreatitis in some patients.

Renal. Dehydration. Electrolyte abnormalities (particularly hypokalemia, hyponatremia, hypophosphatemia). Reduced glomerular filtration rate.

Hematologic. Anemia, leukopenia, thrombocytopenia.

Refeeding syndrome. A dangerous complication of restarting nutrition too quickly in severely malnourished patients. Rapid shifts in phosphate, magnesium, and potassium can produce cardiac arrhythmias, seizures, and death. Refeeding syndrome is prevented by starting refeeding at a modest caloric level, monitoring electrolytes daily during initial refeeding, replacing thiamine and other vitamins, and increasing calories gradually.

Structural brain changes. Reduced gray and white matter volume in severe anorexia. Most changes reverse with sustained weight restoration, though cognitive symptoms may lag behind physical recovery.

Differential diagnosis

Several conditions overlap with anorexia and need to be distinguished.

Bulimia nervosa involves binge eating followed by compensatory behaviors, without the significant underweight of anorexia. The two conditions can transition into each other over time.

Binge eating disorder involves binge eating without compensatory behaviors, typically at normal or above-normal weight.

Avoidant/restrictive food intake disorder (ARFID) involves restriction of food intake without the body image disturbance and fear of weight gain characteristic of anorexia. Often begins earlier and involves sensory sensitivities, fear of aversive consequences (choking, vomiting), or apparent lack of interest in food.

Depression with reduced appetite can produce weight loss but doesn't involve the driven restriction and body image disturbance of anorexia. The two often co-occur.

Anxiety disorders, particularly OCD, share some features (rigidity, ritualized behavior) but don't involve the specific eating and weight focus.

Medical causes of weight loss must be ruled out, particularly in atypical presentations: gastrointestinal conditions, endocrine conditions (particularly hyperthyroidism, diabetes), autoimmune conditions, malignancy. Careful medical workup is standard.

Body dysmorphic disorder shares body image disturbance but focuses on specific perceived defects other than weight.

Why it happens

Anorexia is a complex condition with real genetic contributions, real neurobiological features, real developmental risk factors, and real cultural influences. No single cause explains any case.

Genetics. Twin studies suggest a substantial genetic contribution, with heritability estimates in the 50 to 74 percent range. Watson et al. (2019) published the first well-powered genome-wide association study of anorexia nervosa in Nature Genetics, identifying eight genome-wide significant loci and finding substantial genetic correlations with both psychiatric conditions (OCD, anxiety, depression, schizophrenia) and metabolic traits (BMI, body fat, insulin resistance). This surprised many researchers and reframed anorexia as a "metabo-psychiatric" disorder rather than a purely psychiatric one. This finding is now shaping how the condition is understood.

Temperament and personality. Perfectionism, anxious temperament, cognitive rigidity, harm avoidance, and low self-directedness are associated with higher risk. These features often precede the illness and persist after recovery, suggesting they are traits rather than consequences.

Environmental risk factors. Traumatic experiences, bullying about weight, cultural or family emphasis on thinness, and living in athletic environments that reward low weight (dance, gymnastics, running, wrestling) increase risk in vulnerable people. Puberty, life transitions, and periods of major stress can precipitate onset.

Cultural context. Cultural emphasis on thinness contributes, though anorexia has been described across cultures throughout recorded history. The condition is not created by media; it's shaped by media in vulnerable individuals.

None of this makes the illness anyone's fault. Genes and temperament aren't chosen. Environments aren't either, at the age when the illness usually starts.

What to expect from treatment

Treatment typically involves a team: a physician managing medical stability, a dietitian guiding nutritional rehabilitation, a therapist doing the psychological work, and often a psychiatrist for medication when needed. In adolescents, the family is central. In adults, the person's own commitment carries more of the work, with family involvement when useful and possible.

Levels of care vary from outpatient work through partial hospitalization, residential treatment, and inpatient medical stabilization. The level is chosen by medical risk, current weight and vital signs, ability to eat outside of a structured setting, and severity of co-occurring conditions. The Academy for Eating Disorders (AED) and American Psychiatric Association guidelines specify criteria for level of care.

Weight restoration is usually the first goal because malnutrition worsens every other aspect of the illness. Target weight is typically the weight the person was on their pre-illness growth curve, not a population average BMI. Restoring weight is not the same as recovery; psychological work continues after weight restoration and often takes longer than the physical restoration.

Recovery is not linear. Relapse is common enough that anticipating it and planning for it is part of good treatment rather than a failure. The first year after weight restoration carries the highest relapse risk.

Medical monitoring during acute treatment includes vital signs (particularly heart rate and orthostatic blood pressure), weight, ECG when indicated, electrolytes (particularly during refeeding), liver function, thyroid function, and bone density scanning after prolonged illness.

Most people with anorexia do recover, particularly when treatment starts early. Even in longer-standing illness, meaningful improvement is possible, and continued care with a clinician who understands the illness is worthwhile at any point in its course.

Common comorbidities

Comorbidity is the rule.

Depression occurs in the majority of patients across the lifespan.

Anxiety disorders, particularly generalized anxiety, OCD, and social anxiety, occur in the majority.

Obsessive-compulsive disorder occurs in about 40 percent of patients; the perfectionism and rigidity of both conditions share features.

Trauma history is common. PTSD and complex trauma histories contribute in a substantial minority.

Substance use disorders, particularly alcohol, occur in a substantial minority, more often in the binge-purge subtype.

Personality disorders, particularly avoidant and obsessive-compulsive personality disorders.

Autism spectrum disorder appears at higher rates than in the general population, particularly in restrictive subtypes and in females who were not identified as autistic in childhood.

Type 1 diabetes combined with anorexia produces a particularly dangerous condition sometimes called "diabulimia" (deliberately reducing insulin to induce weight loss), which is medically very serious.

Cultural considerations

Anorexia occurs across cultures, but presentation, recognition, and treatment access vary substantially. Some cultural contexts recognize eating disorders readily; others have limited language for them. Historical presentations from non-Western contexts (Hong Kong, Sub-Saharan Africa, Middle East) sometimes emphasize physical symptoms rather than fear of fat, changing how the condition is described but not the underlying pathology.

Cultural emphasis on thinness contributes to risk but doesn't create the condition. Genetic and temperamental factors are the primary drivers; culture shapes the specific content of the illness.

Immigrant and minority populations may face specific barriers to care, including limited access to specialty eating disorder treatment, cultural stigma, or clinicians unfamiliar with cross-cultural presentations. Under-recognition in these populations is well documented.

Living with anorexia

For the person. Your best chances are with a treatment team you trust, a clinician you can be honest with, and a willingness to stay with the work through the phase when it feels worst. That phase is often the middle, after weight has started to restore and before the psychological work has caught up. Recovery is real; many people who once could not imagine eating without terror now eat ordinary meals without much thought about it.

Building at least one person outside the treatment team who knows what you're going through and can be honest with you (rather than only saying you look great) matters. Isolation is one of the strongest maintenance factors.

Reducing exposure to weight-loss content, diet culture, and social media accounts focused on food and body helps in early recovery. It doesn't have to be permanent; recovery just needs less of that noise while it's fragile.

For family and close friends. Educating yourself about the illness, joining family-based treatment when it is offered, and taking care of your own well-being through the work all matter. Blaming yourself for the illness is not accurate, and blaming the person for the illness is not accurate either. What both of you can control is what happens next. F.E.A.S.T. (Families Empowered and Supporting Treatment of Eating Disorders) provides family-focused resources.