Anorexia Nervosa: Diagnosis, Assessment, and Treatment

Introduction

Anorexia nervosa is a serious eating disorder that results from an individual's intense preoccupation with body weight. Individuals with anorexia have difficulty maintaining a normal body mass index score and frequently make continued efforts to lose weight even when their weight is already abnormally low. The psychological factors that precipitate anorexia can be quite complex, and as a result the diagnosis and treatment of the disorder often require thorough psychological assessment, differential diagnosis, and long-term therapy. This paper explores current research on anorexia and investigates how medical and mental health professionals are using this research to inform their work with anorexic patients (Smith et al., 2011).

Diagnosis of Anorexia Nervosa

According to the American Psychiatric Association's DSM-IV-TR (APA, 1994), a diagnosis of anorexia requires the following criteria:

"Refusal to maintain body weight at or above a minimally normal weight for age and height — for example, weight loss leading to maintenance of body weight less than 85% of that expected, or failure to make expected weight gain during a period of growth, leading to body weight less than 85% of that expected.

Intense fear of gaining weight or becoming fat, even though underweight.

Disturbance in the way one's body weight or shape is experienced, undue influence of body weight or shape on self-evaluation, or denial of the seriousness of the current low body weight.

In postmenarcheal females, amenorrhea — that is, the absence of at least three consecutive menstrual cycles. A woman having periods only while on hormone medication (e.g., estrogen) still qualifies as having amenorrhea.

Types:

Restricting Type: During the current episode of anorexia nervosa, the person has not regularly engaged in binge-eating or purging behavior (self-induced vomiting or misuse of laxatives, diuretics, or enemas).

Binge-Eating/Purging Type: During the current episode of anorexia nervosa, the person has regularly engaged in binge-eating or purging behavior."

While the diagnostic criteria have been clearly outlined for mental health clinicians, many professionals note that it can be quite difficult to make a definitive diagnosis in patients due to factors such as resistance to treatment and denial of the disorder. According to Halse, Honey, and Boughtwood (2008), many patients with anorexia will blame their lack of appetite and weight loss on stomach pains or intolerance to certain foods. In addition, criteria such as amenorrhea require patient disclosure, and an individual who is struggling with the compulsion to lose weight may not be willing to disclose this information to a medical provider.

When a patient's physical symptoms lead medical professionals toward a diagnosis other than anorexia — such as a food allergy — the individual may ultimately use this misdiagnosis to justify her inadequate food consumption. Patients with anorexia may also engage in purging behaviors, such as excessive exercise that they present as athletic training for a specific sport or event. For example, an anorexic patient may consume adequate calories but, by engaging in running workouts of excessive distance or duration, burn far more calories than she takes in. Thus, patients can use seemingly reasonable explanations to prevent diagnosis, and this often occurs because patients typically have a deep psychological need to control and reduce their weight. The potential for resistance, evasive behaviors, and lack of proper diagnosis may also be complicated by age. In the United States, patients who are over the age of 18 can make their own medical decisions, meaning that family members cannot compel them to seek a proper diagnosis or treatment. In some cases individuals may live with the disease for years and avoid any contact with mental health or medical professionals (Halse, Honey, & Boughtwood, 2008).

In addition to these diagnostic difficulties, many professionals note that the current DSM-IV criteria for anorexia nervosa (AN) present significant classification problems that make proper diagnosis very difficult. First, no reference is provided for the weight criteria, so clinicians can have difficulty determining whether a patient's weight falls within the criterion. Second, the subtypes of anorexia are not particularly useful for diagnosing younger patients because these individuals typically exhibit restricting behavior. As a result, many young patients are diagnosed with Eating Disorder Not Otherwise Specified (EDNOS) rather than AN, which often blocks proper treatment and research. Many clinicians have called for a revision of the diagnostic criteria in the DSM-5 (Knoll, Bulik, & Hebebrand, 2010).

According to Keski-Rahkonen et al. (2007), delays in diagnosis and misdiagnosis of anorexia can have serious consequences. A patient's weight may fall to a dangerously low level, often resulting in electrolyte imbalances, heart irregularities, kidney damage, seizures, and extreme fatigue. The fatigue produced by the advancement of the disease can contribute to emotional issues such as depression and anxiety, and may also result in neurological complications that are often irreversible.

A complete and accurate diagnosis of anorexia will often require the participation of family members or significant others as a clinician attempts to gather personal information and medical data regarding the patient. A variety of physical tests — such as BMI calculations and blood chemistry analysis — as well as additional tests may be required to make a differential diagnosis (Knoll, Bulik, & Hebebrand, 2010).

Differential Diagnosis

As previously noted, many individuals with anorexia make extensive efforts to hide or deny their condition, frequently attributing their weight loss and poor diet to other health conditions. As such, a differential diagnosis is essential and must be conducted with the utmost care (Halse, Honey, & Boughtwood, 2008).

The majority of patients who have an underlying medical condition will express concern about their weight loss, while individuals with anorexia may express a distorted body image, a desire to lose more weight, or discomfort and resistance when discussing the topic. Weight loss and loss of appetite can be linked to a wide variety of medical illnesses, including diabetes, gastrointestinal disorders, endocrine disorders, chronic infections, malignancy, and even parasitic infections. A medical doctor must first rule out these conditions through diagnostic tests such as blood testing, ultrasound, stool testing, and colonoscopy. A thorough physical exam is the first step toward an effective and accurate diagnosis; physicians should be particularly alert to physical signs such as very dry skin, low body fat, abnormal heart rate, low blood pressure, and possibly hypothermia (Pritts & Susman, 2003).

In addition to physical illnesses, many psychiatric disorders can produce some symptoms of anorexia. Major Depressive Disorder and Generalized Anxiety Disorder can both result in loss of appetite, weight loss, fatigue, and obsessive-compulsive behaviors. An individual suffering from a major depressive episode may experience a significant drop in body weight, and if she is not fully aware of her condition or is resistant to treatment she may underplay the severity of her depression. A number of psychiatric screening tools are available for the assessment and differential diagnosis of anorexia. One tool, the SCOFF questionnaire, has been widely used by clinicians for screening in the primary care setting. Research shows, however, that it is quite challenging to develop interview tools that will not elicit false positives or allow subjects to provide misleading answers (Pritts & Susman, 2003).

In addition to careful differential diagnosis, clinicians must consider the possible presence of comorbid psychiatric disorders. In a 2003 review of eating disorder diagnostics, Pritts and Susman noted that:

"Major depression is the most common comorbid condition among patients with anorexia, with a lifetime risk as high as 80%. Anxiety disorders, especially social phobia, are also common. Obsessive-compulsive disorder has a prevalence of 30% among patients with eating disorders. Substance abuse prevalence is estimated at 12 to 18% in patients with anorexia…"

Studies also show that personality disorders — especially borderline personality disorder — have a very high rate of comorbidity with anorexia. The complexity of both substance abuse and personality disorders can present major barriers to the proper diagnosis and assessment of anorexia because many individuals with these disorders may be resistant to treatment and avoidant or misleading with practitioners (Pritts & Susman, 2003).