Anorexia has the highest death rate of any mental disorder

Eating disorders are serious mental health conditions involving severe
problems with thoughts about food and with eating behaviour — eating far less
or far more than the body needs. **They are medical conditions, not a
lifestyle choice.** They damage the body's ability to take in nutrition, which
leads to heart and kidney problems and sometimes death. Treatments exist.

The three, and what distinguishes them

Two things in that table are worth stopping on. A person with bulimia nervosa
may be any weight at all, so weight is not a screening tool. And **anorexia
nervosa is the least common of the three and the most serious: it has the
highest death rate of any mental disorder.** Some people die of complications
of starvation, and others die of suicide.

Symptoms, by disorder

Binge-eating: eating unusually large amounts in a set period such as two
hours; eating when full or not hungry; eating fast during a binge; eating to
uncomfortable fullness; eating alone or in secret to avoid embarrassment;
distress, shame or guilt about eating; frequent dieting, possibly without
weight loss.

Bulimia nervosa: all of the above, plus purging, intensive excessive
exercise or fasting. Over time it causes a chronically inflamed and sore
throat, swollen salivary glands in the neck and jaw, worn tooth enamel with
sensitive and decaying teeth (from repeated exposure to stomach acid), acid
reflux and other gastrointestinal problems, severe dehydration, and
electrolyte imbalance — which can cause a stroke or heart attack.

Anorexia nervosa: eating very little to the point of starvation,
excessive exercise, extreme thinness, intense fear of gaining weight, and a
distorted body image. Over time: thinning bones, mild anaemia, muscle wasting
and weakness, thin brittle hair and nails, dry blotchy or yellowish skin, fine
hair growing all over the body, severe constipation, low blood pressure,
slowed breathing and pulse, constant coldness from a drop in body
temperature, faintness, fatigue, infertility, damage to the heart's structure
and function, brain damage, and multi-organ failure.

Cause, risk and treatment

The exact cause is unknown; researchers believe it is a complex interaction of
genetic, biological, behavioural, psychological and social factors. Anyone can
develop one, though they are more common in women and frequently appear in the
teens or young adulthood — and can appear in childhood or later in life.
Depression, anxiety and substance use problems often accompany them.

Diagnosis is a medical history (where honesty about eating and exercise is
what makes help possible), a physical exam, blood or urine tests to rule out
other causes, and tests such as kidney function and an ECG for damage already
done.

Treatment is tailored, and usually involves a team — doctors, nutritionists,
nurses, therapists:

• Psychotherapy, individual, group or family. Cognitive behavioural
  approaches identify and change unhelpful thoughts and build coping skills.
• Medical care and monitoring for the complications.
• Nutrition counselling to reach and hold a healthy weight.
• Medicines — antidepressants, antipsychotics or mood stabilisers — which
  also help the depression and anxiety that often come with it.
• Hospital or residential treatment, combining housing and treatment, for
  serious cases.

Source: National Institute of Mental Health, via MedlinePlus.