The internist next door asks you about his patient with bulimia, who routinely has potassium levels of 2.0 mEq/L. “She admits it’s a problem but thinks she’ll get fat if she stops purging. What can I tell her to get her into treatment?”
That afternoon, your longtime patient Mr. J—age 56 with depression, obesity, and hypertension—arrives for his appointment. With the day’s earlier conversation in mind, you ask him if he has an eating problem. Staring at the floor, he describes a lifelong battle with nighttime eating binges, which he has never mentioned to you before.
Mr. J may have concealed his binge eating because of shame or ambivalence about stopping a psychologically protective behavior. And his eating disorder may be complicating his depression treatment.
But outpatient psychiatrists can often manage patients like Mr. J in consultation with a nutritionist and primary care physician. Eating disorders are treatable,1,2 and many patients can recover. This article describes how to identify eating disorders so that treatment can begin.
Psychiatric comorbidity
Eating disorders are common in outpatient practice (Box)3,4 and coexist with a variety of psychiatric diagnoses (Table 1). For example, in 248 women with anorexia, bulimia, or unspecified eating disorders, 74% had another Axis I disorder, including:
- anxiety disorders (54%)
- affective disorders (52%)
- substance-related disorders (25%).
Eating disorders also are much more common in persons who present with psychiatric problems than in the general population. For example:
- Among 62 patients with a primary diagnosis of obsessive-compulsive disorder, 13% had anorexia or bulimia nervosa and another 18% met subthreshold criteria.6
- In 257 female patients with anxiety disorders, nearly 12% also met criteria for a possible eating disorder.7
‘Subsyndromal’ eating disorders: Most common in outpatient practice
Table 1Some 40% of persons with eating disorders meet DSM-IV-TR criteria for anorexia or bulimia nervosa. The other 60%—with eating disorder, not otherwise specified (ED-NOS)—are divided nearly evenly between binge eating disorder and subsyndromal anorexia or bulimia. Outpatient psychiatrists see these eating disorders most often.
Anorexia and bulimia nervosa prevalence rates are estimated to be 0.3% and 1%, respectively.3 But including ED-NOS patients increases the overall eating disorder prevalence to 2% to 3%—equal to or greater than the combined rates of schizophrenia and bipolar I disorder.
Although considered “subsyndromal,” ED-NOS patients suffer psychopathology, impairment, and medical comorbidity similar to those of persons who meet DSM-IV-TR criteria for anorexia or bulimia nervosa.4
Common psychiatric comorbidities in patients with eating disorders
| Disorder | Comorbidities |
|---|---|
| Anorexia and bulimia nervosa | Anxiety disorders (social phobia, PTSD, OCD) |
| Mood disorders (major depressive disorder, dysthymia, bipolar disorder) | |
| Substance use disorders (more common in patients who binge and/or purge) | |
| Personality disorders (cluster C more common in restricting anorexia, cluster B more common in patients who binge and purge) | |
| Binge eating disorder | Anxiety disorders (PTSD) |
| Mood disorders (major depressive disorder, bipolar disorder) | |
| PTSD: posttraumatic stress disorder | |
| OCD: obsessive-compulsive disorder | |
Who has eating disorders?
Most eating disorder patients are adolescent girls or young women with pronounced body image dissatisfaction. Other patients include:
Atypical young women. Some young women—usually Asian—meet most criteria for anorexia nervosa but lack the characteristic drive for thinness. They tend to have less psychopathology and better prognosis than typical female patients.9
Boys and men. Female-to-male ratios are approximately 11:1 for anorexia, 5:1 for bulimia, and 3:1 for binge eating disorder. Men and boys with eating disorders are similar to their female counterparts but are more likely to report:
- comorbid substance abuse
- having begun weight loss and purging in response to teasing or concerns about health, sports performance, or gay relationships, rather than appearance.10
Middle-aged to late-life. Midlife onset of eating disorders may be precipitated by losses or concerns about aging. In the elderly, eating disorders may be manifestations of complicated bereavement, and ruling out medical causes of weight loss is crucial in this age group.
Night-eating syndrome. Some patients eat at least 25% of daily calories after the evening meal. They experience insomnia, morning anorexia, and sometimes amnesia for the nocturnal eating episodes. Anxiety, depression, or sleep disorders may be contributing factors.12