As the first in a two-part series, this article provides an overview of the clinical characteristics of EDs and key areas for assessment and diagnostic considerations. The first section will briefly discuss the prevalence of EDs. The second section will present key areas for assessment and diagnostic considerations. The final section will provide a summary and clinical pearls.
How Common Are Eating Disorders?
According to the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), there are four primary EDs: (1) anorexia nervosa, (2) bulimia nervosa, (3) binge eating disorder (BED), and (4) avoidant/restrictive food intake disorder (ARFID) (Table A, available in the online version of this article). BED and ARFID do not require body image concerns as core diagnostic criteria and are distinguished based on eating behaviors, recurrent binge eating without regular purging, and avoidance and aversion to food and eating, respectively. Anorexia nervosa and bulimia nervosa are characterized by overvaluation on weight and shape. Anorexia nervosa includes individuals who are under-weight, engage in behaviors to lose or prevent weight gain, and may or may not binge eat or have inappropriate compensatory behaviors. Individuals with bulimia nervosa are typically not under-weight and are stuck in a cycle of binge eating and inappropriate compensatory behaviors (APA, 2013).
Criteria, Clinical Presentation, and Common Differential Diagnoses for Primary DSM-5 Eating Disorders
Prevalence of EDs is increasing despite variation in prevalence estimates across studies, which are due to differences in diagnostic criteria, sampling, small sample sizes, and date of study (Galmiche et al., 2019; Hudson & Pope, 2018). In fact, researchers have postulated that BED may be the most prevalent ED yet the most underdiagnosed and undertreated (Kornstein et al., 2016). With onset typically during adolescence and early adulthood and higher prevalence in Western cultures (Kessler et al., 2013), females are more likely to be diagnosed and receive treatment for EDs (Coffino et al., 2019; Sonneville & Lipson, 2018). However, studies suggest that EDs are increasing in prevalence among males (Coelho et al., 2018; Galmiche et al., 2019); lesbian, gay, bisexual, transgender, queer, intersex, and asexual or allied (LGBTQIA) individuals (Diemer et al., 2018; Donaldson et al., 2018), older adults (Harris & Cumella, 2006; Mangweth-Matzek & Hoek, 2017), and across races and ethnicities (Dooley-Hash et al., 2019; Jennings et al., 2015; Pike et al., 2014).
Key Areas of Assessment
To better assess and treat EDs, health care providers must gain knowledge about their physiological and psychological characteristics. In fact, once EDs are identified, health care providers are more capable of providing evidence-based treatment options. Across EDs, it is essential for health care providers to execute a comprehensive assessment and have a standard practice of using screening tools and requesting laboratory tests for every patient. Table A provides information about clinical presentations and differential diagnoses. Table 1 provides resources and screening tools for EDs.
Resources and Screening Tools for Eating Disorders
Mental Status Exam
A mental status exam provides additional information about mood and affect as well as appearance, speech, psychomotor function, and suicidal ideation and behavior. Given the high prevalence of psychiatric comorbidities, including suicidal intent and non-suicidal self-injury, the mental status exam provides essential information about the presence of symptoms related to psychiatric comorbidities.
Developmental and Social History
Developmental and social history includes developmental milestones, academic progress, occupation, interpersonal relationships, and traumatic events. Individuals with ED often experience negative social interactions that significantly impact their desire to alter body weight or shape (e.g., bullying or teasing about being under- and overweight). In time, they may also become more isolated because they are preoccupied with their shape and weight and compensatory behaviors. In fact, self-esteem for individuals with EDs is very dependent on perceptions of body shape and weight. Indications of impaired psychosocial functioning may include inability to eat with others; avoidance of social events with food; avoidance or refusal of foods based on colors, textures, smell, or temperature; avoidance of food shopping; and avoidance of eating food prepared by someone else.
Family History of Eating Disorders
Given the genetic predisposition and familial influence on EDs (APA, 2013), assessment of family history of EDs or obesity as well as family and cultural norms related to eating, perceptions of body weight and shape, and values is needed. Such information may provide insight about the individual's relationship to food, how it has contributed to the onset or severity of ED symptoms, and treatment targets.
Medical History and Current Medical Problems
Assessment of current and past medical history may provide additional information about EDs and differential diagnoses. The physical examination should include the following: weight, height, pulse, blood pressure, hydration status, and skin, neurological, dental, cardiac, abdominal, and extremity examinations (Mehler & Anderson, 2017). Medical conditions can lead to changes in appetite, weight, or food in-take that can be ruled out with a thorough history and physical examination along with laboratory studies. These illnesses include chronic infection and infectious diseases, thyroid disease, Addison's disease, inflammatory bowel disease, connective tissue disorders, cystic fibrosis, peptic ulcer disease, disease of the esophagus or small intestine, celiac disease, diarrhea, diabetes mellitus, and occult malignancies (Lock & La Via, 2015).
Regarding EDs, medical complications may include cardiovascular abnormalities, such as bradycardia, prolonged corrected QT intervals, dysrhythmias, orthostatic pulse, blood pressure instability, hypothermia, renal abnormalities (e.g., pyuria, hematuria, proteinuria), and electrolyte abnormalities (e.g., hypokalemia, hypocalcemia, hypomagnesemia, hypophosphatemia). Although most physiological disturbances associated with malnutrition are reversible by restoring healthy nutritional practices, some are not completely reversible, such as loss of bone mineral density (Mehler & Brown, 2015; Palla & Litt, 1988).
An electrocardiogram may be indicated for individuals who are very thin, complaining of palpitations, or have other signs or symptoms of cardiovascular concern. A dual-energy radiographic absorptiometry scan may be useful, particularly for individuals with irregular menses, with mood disorders, and/or who smoke cigarettes. Genetic testing may be helpful to rule in or out a deletion or translocation syndrome. Across EDs, comprehensive laboratory testing at the initial evaluation may assist in ruling out other genetic and biological diseases. Inappropriate compensatory behaviors (e.g., self-induced vomiting; misuse of laxatives, diuretics, enemas) may cause disturbances that lead to abnormal laboratory findings; however, quite often, individuals with anorexia nervosa exhibit no laboratory abnormalities until the ED has significantly progressed (Mehler & Brown, 2015). Laboratory testing should include but is not limited to: comprehensive blood chemistry with differential, serum electrolytes, calcium, magnesium, and phosphate levels; liver function tests and albumin; serum salivary amylase levels; vitamin D; serum BUN and creatinine levels; blood glucose levels; T4 and thyroid-stimulating hormone (TSH) levels; testosterone level; urinalysis; and pregnancy test (Mehler & Anderson, 2017; Miller et al., 2005).
Psychiatric history includes current and past psychotherapeutic treatment (e.g., level of care, dates, duration, location, diagnosis, treatment modality), pharmacological treatment (e.g., medication name, dose, duration, dates, response, efficacy), and adjunct therapies (e.g., family or couples, group, support, alternative, nutritional). Additional information may include illness duration for current diagnoses, and for adults, highest and lowest lifetime body mass index (BMI) or weights and age at which these occurred. Most individuals with EDs will have at least one other psychiatric disorder, and psychiatric comorbidities are predictors of health services utilization and prognosis (Keel & Brown, 2010; Weigel et al., 2019). Because nonweight-related appearance concerns occur in individuals with EDs (Kollei et al., 2013), body dysphoria disorder can be a comorbidity. The most common psychiatric comorbidities include depression, anxiety, and personality, trauma-related, and substance use disorders (Afifi et al., 2017; Bahji et al., 2019; Kimber et al., 2017; Udo & Grilo, 2019). Thus, assessments of mood, anxiety, substance use, trauma, and suicidal thoughts and behavior are useful.
Eating Patterns and Compensatory Behaviors
Assessment of eating patterns includes frequency, amount, type, and location of food intake (Wolfe et al., 2016). Considerations of existing guidelines (e.g., dietary, BMI) and the individual's weight history, body type, and physiological disturbances are helpful. Individuals with ARFID tend to lack interest in eating or food, which leads to food restriction or avoidance and eventually weight loss or malnutrition. Diagnostic markers of ARFID may include malnutrition, low weight, growth delay, and a need for artificial nutrition (APA, 2013). However, for anorexia nervosa, individuals tend to restrict intake and have low weight because of significant weight loss or failure to meet expected weight gain or maintain normal developmental trajectories. Diagnostic features of anorexia nervosa may include: fasting or excessive physical activity to lose or maintain low weight; manipulation of medication dosage to lose or maintain low weight; preoccupation with thoughts of food; binge eating episodes and inappropriate compensatory behaviors; and purging behaviors after consumption of small amounts of food to maintain low weight (APA, 2013).
For binge eating episodes, information to gather includes frequency, duration, time of day, types and amount of food, and associated feelings and events. Individuals who engage in binge eating may be hesitant to disclose details because they often develop a sense of guilt and shame about binge eating episodes and tend to secretly engage in the behavior. For BED, binge eating episodes are not accompanied by compensatory behaviors, but quite often, individuals experience embarrassment, guilt, and/or feeling of disgust after the episodes, which may lead to more food consumption. For bulimia and anorexia nervosa, the fear of gaining weight leads to inappropriate compensatory behaviors to counter the size and/or frequency of binge eating episodes. In fact, individuals with bulimia nervosa tend to restrict caloric intake or fast between binge eating episodes. Thus, assessing types and frequency of inappropriate compensatory behaviors is useful. Although self-induced vomiting is the most common, other inappropriate compensatory behaviors include, but are not limited to, misuse of laxatives, diuretics, and enemas and/or excessive exercise
Cognitive distortions about food and weight are commonplace in EDs. For example, individuals may have dichotomous thinking about foods as “good” or “bad,” or body image concerns may manifest as complaints about body parts (e.g., thighs, hips, stomach). However, ARFID and BED do not require body image concerns as core diagnostic criteria and are based primarily on eating behaviors. Overall, assessment of psychosocial environment, psychiatric comorbidities, and life stressors are needed because these factors can negatively influence self-esteem, body image, and cognitive distortions, which contribute to ED symptoms.
Other Specified or Unspecified Eating Disorders. For these diagnoses, individuals do not meet the full criteria for one of the primary EDs. For example, with BED or bulimia nervosa, individuals do not meet the required frequency or duration of binge eating and/or compensatory behaviors. Atypical anorexia nervosa is characterized by having the same key features of anorexia nervosa except being under-weight (APA, 2013). In fact, individuals with atypical anorexia nervosa may have significant weight loss and are within or above normal weight ranges. The key characteristic of purging disorder is engaging in recurrent weight control behaviors to influence weight or shape in the absence of binge eating. Finally, night eating syndrome is characterized by recurrent episodes of night eating (after evening meal or waking to eat) associated with significant distress or impairment in functioning.
Pediatrics. Most pediatric patients with EDs require medical intervention and need to receive ongoing medical monitoring in concert with psychiatric treatment. Although minimal scientific evidence exists for using weight as a marker of illness severity in children and adolescents, pediatric weight is based on age and gender norms according to BMI percentiles, with BMI below the 10th percentile being consistent with the degree of malnutrition associated with anorexia nervosa (APA, 2013). Signs and symptoms of EDs may present differently in children and adolescents compared to adults. Developmental stage should be considered and often information from primary caregivers is critical because self-report can be unreliable (e.g., lack insight, minimization, more likely to deny seriousness). For example, verbalizing abstract thoughts may not be possible for children and they may use ED behaviors, such as food refusal, as nonverbal representations of emotional experiences. Other examples include variations in maladaptive behaviors, such as constant compulsive movements, change in appearance (e.g., loose-fitting clothing or heavier clothing for warmth), and fluid restriction. In addition, primary caregivers can provide information about behavioral changes, such as changes in being withdrawn, depressed, and anxious (Lock & La Via, 2015).
Psychosis. Undernutrition or malnutrition can produce clinical presentation that resembles psychosis but is usually transient. However, clinical phenomena include EDs serving as a prodrome or early stage of psychosis and EDs emerging as a result of the treatment of psychosis (Seeman, 2014). Although there is no established connection between eating and psychotic disorders, a subset of individuals may have both an ED and a psychotic disorder (Alves Pereira et al., 2016). Individuals with a psychotic disorder may have delusions that lead to food aversions and dangerous eating behavior, but this is not an ED. Research in the common dimensions of illness for both disorders is accelerating.
Pregnant Women. Estimated occurrence of EDs among pregnant women is 7.5% (Dörsam et al., 2019), and places the woman and fetus in jeopardy. Pregnant women with EDs have increased risk of antepartum hemorrhage and hyperemesis gravidarum, and higher rates of spontaneous abortion, cesarean sections, and postpartum depression (Mantel et al., 2019). Detrimental fetal outcomes can include presence of lower or higher birth weights, intrauterine growth restriction, small head circumferences, neurobehavioral dysregulations early after birth, premature deliveries, and increased perinatal mortality (Ward, 2008). Clinical presentation varies and may be influenced by whether the pregnancy was intended/anticipated; social, emotional, and financial supports; and age. Indeed, EDs may be linked to lack of acceptance of the pregnancy, a way to inhibit body disfigurement, or an attempt to keep the pregnancy secret. Despite inconsistencies in optimal approaches to treating EDs during pregnancy, pregnant women with EDs require medical intervention and ongoing surveillance along with psychiatric treatment. Balanced nutrition is critical to ensure positive obstetrical outcomes, whereas lack of balanced nutrition may lead to negative consequences. Moreover, early intervention strategies and a multidisciplinary approach are preferential especially because pregnant women require significantly more nutrients typically starting in the 4th month of gestation. Although, pregnancy may be a trigger for the continuation or even deterioration of symptoms, especially for BED, evidence suggests an improvement of eating behaviors during pregnancy (Dörsam et al., 2019).