Anorexia nervosa typically has numerous complications. The disease has one of the highest death rates among all mental illness, hovering around five percent or higher than this.

Death may occur suddenly- even when someone is not severely underweight. This may result from abnormal heart rhythms (arrhythmias) or electrolyte imbalance. In fact, it was the anorexia related death of singer Karen Carpenter in 1983 that catapulted the disease into the public arena.

Other serious or life threatening complications commonly included:

* Anaemia
* Heart problems, such as mitral valve prolapse, abnormal heart rhythms and heart failure
* Bone loss, increase risk of fractures later in life.
* Lung problem resembling emphysema
* In female, absence of a period
* In male, decreased testosterone
* Gastrointestinal problems, such as constipation, bloating or nausea
* Electrolyte abnormalities, such as low blood pressure, sodium and chloride
* Kidney problems

If a woman with anorexia becomes severely malnourished, every organ of her body can attain damage, including the brain, heart and kidneys. This damage may not be fully reversible, even when the ailment is under control.

In addition to the host of physical complications, women with anorexia nervosa have other mental disorders. They may include:

* Depression
* Anxiety disorder
* Personality disorder
* Obsessive-compulsive disorder
* Drug abuse

The co-occurrence of these disorders with anorexia can make the disease more difficult to treat