11th Jan 2023
Anorexia nervosa and bulimia nervosa are eating disorders characterized by distorted body image, preoccupation with food, and extreme eating habits used to control weight.  Approximately 90% of eating disorder patients are female, and the prevalence in males is not yet fully understood.  Research has found that between 0.9%-2% of females will develop anorexia nervosa at some point in their lives.  On the other hand, between 1.1%-4.6% of females will develop bulimia nervosa.  Commonly called simply anorexia and bulimia, these disorders have many similarities, but some critical differences in symptoms, causes, and treatment options are important to understand.
Anorexia nervosa is characterized by an unhealthy relationship with food and a distorted body image. Individuals with this disorder try to keep their body weight down through methods such as starvation or excessive exercise. They usually maintain a body weight far below average.
The DSM-5 highlights the following criteria to be met for a diagnosis of anorexia:
Like anorexia, bulimia nervosa is characterized by an unhealthy relationship with food and body weight. However, individuals with bulimia also have episodes of binge eating, where they consume larger than normal quantities of food, followed by compensatory, purging behaviors. 
The DSM-5 highlights the following criteria to be met for a diagnosis of bulimia:
An episode of binge eating is defined by:
Anorexia and bulimia share many of the same symptoms. Patients with either eating disorder may experience the following symptoms:
Those with anorexia are more likely to experience the following:
On the other hand, those with bulimia are more likely to experience the following:
Binge eating and purging through vomiting, laxatives, enemas, or diuretics is much more common in bulimia patients. However, this can also occur in individuals with binge eating and purging-type anorexia.  Many in this category do not binge and will only purge after eating small amounts of food.
The main diagnostic differentiator between these two eating disorders is body weight. While those with anorexia maintain a significantly low body weight, those with bulimia maintain a normal to above-normal weight for their height, age, and sex. 
Fasting is much less common with bulimia, but individuals may eat significantly less than normal in between binge eating episodes. 
The exact causes of anorexia and bulimia are not yet fully understood. However, researchers believe genetic and environmental factors play a part in developing these mental health disorders.
Individuals with immediate family members who have suffered from anorexia or bulimia are more likely to develop an eating disorder themselves.  A family history of other mental health issues can also increase the risk.
Environmental factors that increase the risk of an eating disorder include stressors, depression, and internalizing society’s ideal of a thin body type.  As a result, these disorders are more commonly seen in Western cultures.
Anorexia is associated with certain personality types and traits. Patients tend to be perfectionists, who are sensitive to criticism, and frequently doubt themselves.  They also commonly feel like they lack control in their lives.
Individuals with the disorder tend to have a history of anxiety disorders or obsessive-compulsive disorder.  They also have a history of dieting. Some researchers believe that positive reinforcement from dieting, such as weight loss or compliments, can contribute to the development of anorexia. 
While both disorders are associated with early childhood experiences, bulimia is connected to some unique experiences. For instance, bulimia is linked to a history of sexual abuse or assault, while anorexia is not.  Bulimia is also more commonly connected to a past of childhood obesity. 
Individuals with this disorder tend to have difficulties with impulse control.  Additionally, bulimic patients frequently suffer from depressive disorders.
Treatment for anorexia and bulimia focuses on nutritional rehabilitation, family therapy, and individual psychotherapy. Medications, especially antidepressants, may also be used.
The first goal of anorexia treatment is to get the individual back to a healthy weight. Depending on the severity of the patient’s condition, this may be done through hospitalization, inpatient care, or outpatient care.  Patients with anorexia are much more likely to require hospitalization than patients with bulimia. 
The Maudsley approach, a type of family therapy, is commonly used to treat anorexia in adolescents. Parents are educated on supporting their child in developing healthier eating habits.  This therapy also includes a cognitive component to address the patient’s distorted body weight and shape perceptions.
Research suggests that family therapy is more effective than individual therapy for anorexia treatment.  However, individual psychotherapy, including cognitive-behavioral therapy (CBT) and interpersonal therapy (IPT), can effectively reduce the chance of relapse once a healthy weight has been reached.  These therapies address the underlying causes of the disorder.
While there is not enough evidence for treating anorexia with medications alone, they may help treat comorbid conditions that contribute to the severity, such as depression, OCD, and anxiety. 
Since bulimia patients are typically not underweight, treatment is usually outpatient. Treatment focuses on improving the individual’s relationship with food and their body and reducing binging and purging cycles.
The most common therapeutic approach for treating bulimia is CBT, which helps patients challenge unhealthy, negative beliefs.  It also helps them develop healthier behaviors and eating patterns.
While more evidence exists for the effectiveness of CBT, IPT is also becoming a popular treatment option. In IPT, individuals work to improve their relationships and social skills. This helps with underlying depressive symptoms and improves their support network. 
Research has found that antidepressants, particularly SSRIs, are very effective for treating bulimia, even if the patient does not have a concurrent diagnosis of depression.  These medications help to reduce binging and purging behaviors.  SSRIs can also help with body image and attitudes toward food. 
Recovery from anorexia and bulimia is a long-term process. Relapses are common, so ongoing treatment is recommended for maintenance.
Anorexia generally has a poorer prognosis than bulimia and requires a more extended recovery. It also has the highest mortality rate of any psychological condition.  Still, about 50% of patients fully recover, and 30% partially recover. 
Conversely, bulimia patients have higher recovery rates. Research has found that 80% of patients typically fully recover after treatment.  Relapse is still a concern, affecting up to 20% of patients. 
Due to the nature of the symptoms, you cannot meet the criteria for a diagnosis of both anorexia nervosa and bulimia nervosa simultaneously.  However, many individuals diagnosed with one disorder will eventually develop the other.
Research has found that up to 50% of those diagnosed with anorexia will develop bulimia at some point in their lives.  On the other hand, only about 10% of those with bulimia will go on to develop anorexia.