For a diagnosis of Anorexia Nervosa in adults, what BMI is considered significantly underweight?

A diagnosis of Anorexia Nervosa in adults requires specific criteria regarding body weight, and a Body Mass Index (BMI) of below 18.5 is indeed classified as significantly underweight. This cutoff is used in the DSM-5 to indicate a level of weight that is substantially below the average for a given height and is associated with a range of health risks.

Individuals with a BMI below 18.5 are at risk for medical complications due to inadequate nutritional intake and can experience severe physiological consequences from malnutrition. This BMI threshold is essential in assessing the severity of the disorder and aids clinicians in determining appropriate treatment strategies.

While lower BMIs, such as those below 16, indicate a more severe level of weight loss and are associated with higher levels of health risk, they are not used as the primary criteria for diagnosing the disorder. The DSM-5 prioritizes the benchmark of 18.5 to reflect the critical level of danger that underweight individuals face while also encompassing a broader range of cases. Therefore, understanding the designated BMI classifications is crucial for accurate diagnosis and subsequent intervention.