Anorexia nervosa (AN) is a serious psychiatric illness defined by self-starvation, an intense fear of gaining weight, and a distorted body image. This disorder forces individuals to severely restrict their food intake, leading to dangerously low body weight. The profound physical and mental toll of AN raises a fundamental question about its impact on an individual’s lifespan and longevity.
Anorexia Nervosa and Mortality Rates
Anorexia nervosa significantly shortens lifespan, carrying one of the highest mortality rates among all psychiatric conditions. The risk of premature death is quantified using the Standardized Mortality Ratio (SMR), which compares observed deaths in individuals with AN to expected deaths in the general population. Studies indicate that individuals with AN have an SMR ranging from approximately 4.37 to 5.86. This means they die at a rate four to six times higher than their peers, a risk that persists for decades after diagnosis.
Physical Mechanisms of Premature Death
Chronic malnutrition inflicts widespread damage across all organ systems, making the cardiovascular system particularly vulnerable. Sudden cardiac death is the most common medical cause of death in individuals with AN. The heart muscle can atrophy due to the lack of necessary protein and energy, diminishing its ability to pump blood effectively. This physical decline often manifests as severe bradycardia (slow resting heart rate) and hypotension (low blood pressure).
A more immediate threat comes from critical electrolyte imbalances, particularly low levels of potassium (hypokalemia). These imbalances destabilize the heart’s electrical rhythm, leading to fatal arrhythmias, or irregular heartbeats.
The body’s profound state of cachexia (severe physical wasting) compromises organ function throughout the body. Kidneys may fail due to chronic dehydration and poor circulation. Furthermore, malnutrition severely suppresses the immune system, leaving the body highly susceptible to infections like pneumonia, which can become overwhelming and fatal.
Psychiatric Comorbidity and Suicide Risk
Mortality in AN is a two-pronged problem, with suicide representing the other major contributor to premature death alongside medical complications. Individuals with AN have a markedly increased risk of dying by suicide, a rate estimated to be up to 18 times higher than that of the general population. Approximately one in five deaths among individuals with AN is attributed to suicide.
Anorexia nervosa rarely occurs in isolation, frequently co-occurring with other serious psychiatric conditions that dramatically heighten the suicide risk. The presence of conditions like major depressive disorder, anxiety disorders, or substance use disorders acts as a significant risk multiplier. The profound mental anguish and hopelessness associated with severe AN contribute to this high rate of intentional self-harm.
Factors Influencing Long-Term Prognosis
The degree to which AN shortens an individual’s lifespan is heavily influenced by several prognostic factors. A major factor is the duration of the illness; a longer period between symptom onset and effective treatment is consistently associated with a worse outcome and higher mortality risk. Therefore, early identification and intervention are strongly linked to a better chance of full recovery.
The severity of the illness, particularly a very low Body Mass Index (BMI) at diagnosis, is another significant predictor of poor survival. Conversely, an early age at the time of first specialized treatment may be associated with a more favorable prognosis. Individuals who achieve and maintain a full recovery from AN significantly reduce their long-term mortality risk, highlighting that recovery remains achievable and impactful.