Anorexia nervosa (AN) is a serious psychiatric condition characterized by self-imposed starvation, an intense fear of gaining weight, and a distorted body image. This disorder involves severe restriction of energy intake, leading to profound physical consequences. AN affects every major organ system, causing chronic malnutrition that can rapidly become life-threatening. The medical and psychological toll makes AN one of the deadliest psychiatric illnesses.
The High Mortality Rate of Anorexia Nervosa
Anorexia nervosa carries the highest mortality rate of any psychiatric diagnosis. Studies using the standardized mortality ratio (SMR)—which compares observed deaths in patients to expected deaths in the general population—show SMRs ranging from 5.9 to over 10.5. For young females, the death rate can be up to 12 times higher than for their peers.
The elevated risk is influenced by the duration and severity of the illness. A greater percentage of weight loss from a person’s ideal body weight substantially increases the danger. Severely malnourished patients, particularly those requiring inpatient care, exhibit even higher SMRs, sometimes reaching nearly 16. This reflects a combination of intentional self-harm and the physical deterioration caused by starvation.
Immediate Physiological Causes of Death
The most frequent cause of death in people with anorexia nervosa is heart failure, accounting for an estimated one-third of all fatalities. Prolonged starvation forces the body into severe energy conservation, dramatically slowing the heart rate (bradycardia). The heart muscle shrinks (atrophy) as the body breaks down tissue for fuel, diminishing its ability to pump blood effectively.
Sudden cardiac death often results from a lethal heart rhythm disturbance, or arrhythmia. Malnutrition can lead to a prolonged QT interval, an electrical delay that increases the risk for a chaotic, fatal arrhythmia called Torsade de Pointes. This sudden collapse can occur even in individuals who are not visibly emaciated, as the heart’s electrical stability is compromised.
Severe electrolyte imbalances are another direct physiological threat. Restriction of intake or behaviors like self-induced vomiting and laxative misuse deplete the body’s stores of minerals like potassium (hypokalemia). Potassium is essential for regulating nerve and muscle function, particularly the heart’s rhythm. Low potassium levels can trigger an unpredictable and fatal cardiac arrest.
Beyond the cardiovascular system, chronic starvation causes multi-organ failure. The lack of energy and nutrients impairs the function of the liver, intestines, and kidneys, which are required for detoxification and metabolic balance. In severe cases, dehydration and profound hypoglycemia (dangerously low blood sugar) can lead to coma and death. The body’s inability to maintain basic metabolic processes ultimately leads to an irreversible systemic shutdown.
Suicide Risk and Co-occurring Fatalities
While medical complications are the primary cause, suicide is the second leading cause of death among people with anorexia nervosa. Psychological distress, social isolation, and neurobiological changes caused by malnutrition contribute to a significantly increased risk of self-harm. Individuals with AN are estimated to be 18 times more likely to die by suicide than their age and gender-matched peers.
Suicide accounts for approximately 25% of deaths associated with the disorder. This risk is compounded by co-occurring mental health conditions, such as depression, anxiety, and substance use disorders. Patients who engage in purging behaviors, such as self-induced vomiting or laxative abuse, face an even higher risk of suicide attempts.
Another distinct, treatment-related risk is refeeding syndrome, which occurs when nutrition is reintroduced to a severely malnourished body. This metabolic complication involves a sudden shift in fluids and electrolytes, including dangerously low levels of phosphate (hypophosphatemia). This rapid change can overwhelm the heart and lead to respiratory or cardiac failure, making nutritional rehabilitation a medically fragile period.
Recognizing Signs of Imminent Danger
Recognizing signs of imminent medical danger in an individual with anorexia nervosa is paramount for survival. One urgent indicator is extreme bradycardia, where the resting heart rate drops below 50 beats per minute. This slow rate signals that the body’s energy conservation mechanism is reaching a perilous limit.
Fainting or severe dizziness (syncope or orthostatic hypotension) signals that the heart and circulatory system are failing to cope. Any manifestation of severe electrolyte imbalance, such as muscle cramps, tremors, or profound confusion, demands immediate medical assessment, as this can precede a fatal arrhythmia. Rapid and severe weight loss, extreme fatigue, persistent cold intolerance, or dramatic drops in body temperature indicate a collapse of the body’s core regulatory systems. These symptoms are serious medical emergencies that require immediate hospitalization for life-saving stabilization.