Many mental disorders are dangerous illnesses that can have severe consequences, even death. For example, major depression, bipolar disorder and borderline personality disorder have all been linked to increased mortality rates in patients. One class of mental disorders that is thought to be particularly dangerous are eating disorders.

Eating disorders include different diagnoses such as:

• Anorexia nervosa: This disorder is characterized by a fear of getting overweight and a desire to be thin.
• Bulimia nervosa: This disorder is characterized by binge eating episodes followed by vomiting or other behaviors to prevent weight gain.
• Binge eating disorder: This disorder is characterized by binge eating episodes but does not include vomiting or other behaviors to prevent weight gain, such as in bulimia nervosa.
• Eating disorder not otherwise specified: These are several different eating disorders that do not meet the diagnostic criteria for the aforementioned diagnoses.

What has been lacking in the psychological literature is an up-to-date study on how deadly eating disorders are.

A new meta-analysis on how deadly eating disorders are

A new study, just published in the scientific journal Clinical Psychology Review, was aimed at closing this gap in the literature (Krug and co-workers, 2025). The research team, led by scientist Isabel Krug from the School of Psychological Sciences at the University of Melbourne, conducted a so-called meta-analysis of data from previously published studies on eating disorders. In a meta-analysis, scientists do not collect new data from patients. Instead, they use advanced statistical methods to integrate the data from already published studies together. This way, much larger sample sizes can be realized, and more robust and trustworthy research findings can be generated. Overall, data were obtained from 31 published studies. The dataset included data from 262,982 patients with an eating disorder. Overall, the included studies reported 5,993 death cases.

In the analysis, the scientists focused on a statistical measure called the standardized mortality ratio or SMR. SMR is a standard measure in clinical epidemiology and gives the ratio of observed deaths in a group of patients compared to the expected deaths based on data from the general population. Thus, an SMR of 1 shows that patients with a specific disorder have the same mortality rate as the general population. In comparison, an SMR of 10 shows that a patient with the disorder is 10 times more likely to die than someone from the general population. Using the SMR, it is easy to compare how deadly different mental disorders are. By multiplying the SMR with 100, it can easily be transferred to percentages.

Anorexia Nervosa is the deadliest eating disorder

The analysis of the study clearly showed how dangerous eating disorders are. When all patients with eating disorders were analyzed together, the SMR was 3.39. Thus, patients with any eating disorder are 339 percent more likely to die than someone from the general population. When the different eating disorders were analyzed separately, the data clearly showed that anorexia nervosa is the deadliest eating disorder. Patients with anorexia nervosa have a 521 percent increased chance of dying compared to someone from the general population. For bulimia nervosa, it was 220 percent, for binge eating disorder 146 percent and for eating disorder not otherwise specified 251 percent. This makes eating disorders one of the deadliest groups of mental disorders, with only a few other disorders, such as opioid substance abuse, being more dangerous.