Anorexia nervosa and bulimia nervosa are serious psychiatric illnesses related to disordered eating and distorted body images. They both have significant medical complications associated with the weight loss and malnutrition of anorexia nervosa, as well as from the purging behaviors that characterize bulimia nervosa. No body system is spared from the adverse sequelae of these illnesses, especially as anorexia nervosa and bulimia nervosa become more severe and chronic. We review the medical complications that are associated with anorexia nervosa and bulimia nervosa, as well as the treatment for the complications. We also discuss the epidemiology and psychiatric comorbidities of these eating disorders.
Anorexia nervosa and bulimia nervosa are serious psychiatric illnesses with substantial morbidity and mortality. Anorexia nervosa is the psychiatric illness with the highest mortality rate. Mortality also is increased in patients with bulimia nervosa. In both anorexia nervosa and bulimia nervosa, much of the increased mortality rate is attributable to the medical complications inherent to these 2 illnesses.
Although anorexia nervosa and bulimia nervosa are defined as separate disorders in the psychiatric Diagnostic and Statistical Manual 5th Edition, they both fall into the category of disordered eating, driven by an irrational fear of normal body weight and a desire for thinness, and leading to body image distortion. Cultural ideals of beauty and thinness may incite the development of disordered eating in vulnerable individuals, who have a genetic predisposition toward anxiety and perfectionism. Both starvation and purging may initially calm these feelings of anxiety and reduce obsessions and compulsions via a serotonergic neuronal pathway.
During the course of anorexia nervosa and bulimia nervosa, comorbid mental disorders also emerge as a result of altered neurotransmitter metabolism or endocrine changes that result from caloric deprivation. Approximately 50% of adolescent patients with anorexia nervosa meet criteria for at least 1 comorbid psychiatric illness. Eating disorders are strongly associated with mood and anxiety disorders, and the type and severity of these comorbidities are increased in patients who have the most severe eating disorders.
In addition, patients with bulimia nervosa who have comorbid borderline personality disorder have poorer outcomes than those without borderline personality disorder when both groups are treated with psychotherapy and pharmacotherapy. Psychiatric comorbidity, as well as a history of suicidal or self-harm ideation, and comorbid mental illnesses all confer an increased risk of death in patients with eating disorders. Problems socializing and difficulties with being assertive are factors that contribute to maintaining an eating disorder. Temperament traits of harm avoidance, combined with high reward dependence, are protective factors seen more commonly in patients who recover from eating disorders.
Treatment of anorexia nervosa and bulimia nervosa is multidimensional. In addition to nutritional rehabilitation, cognitive-behavioral psychotherapy and family therapy have been shown to be effective in treating patients with anorexia nervosa, although the benefit of these therapies have been noted primarily in the weight maintenance phase of treatment.
There is only minimal to moderate evidence that psychiatric medications are efficacious in treating patients with anorexia nervosa. Despite the prevalence of mood and anxiety symptoms in patients with anorexia nervosa, medications used to treat these conditions are not necessarily useful treatment adjuncts for reducing the symptoms of anorexia nervosa. In one study, fluoxetine assisted in preventing relapse in weight-restored patients with anorexia nervosa. However, this finding was not replicated in a subsequent study. Although there may be evidence for using antidepressants in the weight maintenance phase, antidepressants do not ameliorate eating disorder pathology in patients who are acutely underweight. The poor response to antidepressants is believed to result from starvation-induced abnormalities in serotonin receptors.
In addition to concerns regarding the efficacy of antidepressants in patients with anorexia nervosa, there is also considerable debate as to the efficacy of antipsychotics in treating their symptoms. Low-dose antipsychotic medications may be useful in treating delusional beliefs regarding body image, intense ruminations about food, and the hyper-arousal and anxiety induced by having to face weight restoration. Although atypical antipsychotic medications promote weight gain in normal-weight individuals, they do not have this effect in patients with anorexia nervosa.However, patients with eating disorders may not accept reassurance in this regard. Despite the paucity of associated weight gain, there remains concern that the risk of using these medications outweighs their potential benefit First-generation antipsychotics (typical antipsychotics) lower the seizure threshold. Side effects of second-generation antipsychotics (atypical antipsychotics), such as orthostasis, prolonged rate-corrected QT (QTc), and hepatotoxicity, are of concern.
Despite continued debate regarding the usefulness of pharmacotherapy in patients with anorexia nervosa, pharmacotherapy for bulimia is well established. Fluoxetine (at doses of ≥60 mg) is approved by the Food and Drug Administration for bulimia nervosa, and other selective serotonin reuptake inhibitors (as well as other classes of antidepressants) have been found to be useful in treating patients with bulimia nervosa. The effect of fluoxetine in treating the symptoms of bulimia nervosa seems to be independent of its effects on mood and is reportedly related to the effects of the medication on satiety, thereby reducing binge eating. Cognitive behavioral therapy is a well-established psychotherapeutic treatment for bulimia nervosa.
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-Patricia Westmoreland, MD, Mori J. Krantz, MD, Philip S. Mehler, MD
This article originally appeared in the January 2016 issue of The American Journal of Medicine.
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