A Review of the Etiology and Epidemiology of Anorexia Nervosa

Abstract

Anorexia Nervosa is an eating disorder that affects many young women in this country. It is characterized by an acute reduction in weight, an intense fear of weight gain, body image disturbances and amenorrhea. The etiology and epidemiology of this disease is both complex and unclear. The etiology of the disease can be impacted by biological, societal, psychological, cultural, and familial factors. Research suggests that elevated serotonin levels have been implicated in the development of anorexia nervosa Investigators have also identified the public glorification of thinness by western civilization as a contributing factor to the susceptibility of young women to developing this disease. Various personality traits and disorders may be associated with the etiology of anorexia. Several studies report a high prevalence of avoidant personality disorder and obsessive-compulsive personality disorder in anorexia samples. The frequency of anorexia nervosa amongst culturally diverse populations is significantly less than in white, westernized populations. Familial factors appear to play a role in the development of this disease. Research reveals that families of anorexics are often characterized as enmeshed and negating of the patient’s emotional needs. The epidemiology of anorexia nervosa is as multifaceted as the development of the disease. A combination of protocols is often used to treat this disorder. These protocols include restoration of a healthy weight, individual and family therapy, body image therapy and nutritional education.

The definition of psychopathology is quite simple. Psychopathology is the study of abnormal behavior. It is the characterization of what constitutes normal and abnormal behavior that is utterly complex and even controversial. There are several approaches one can employ when defining and diagnosing psychopathology. Davison & Neale suggest that ‘abnormal behavior’ is statistically infrequent, violates cultural or societal norms, creates personal distress and suffering, impairs the individual functionally, and is an unexpected response to environmental cues” (Dawson and Neale 1994). However, this definition is not complete as stated. I would amend the last sentence to further describe the origin of cues that might contribute to psychopathology. The revised sentence would read “(psychopathology)… is an unexpected response to environmental and internal cues”. This revision allows for the influence of internal factors on psychopathology. I believe the definition should also allow for a more subjective diagnosis of psychopathology. If a concerned person evaluates their current situation or behavior as abnormal, then that individual appraisal meets my definition of psychopathology. The individual is in the best position to assess their current condition as normal or abnormal.

Most practitioners rely on Western classification systems such as the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM IV) as standard guidelines to define psychopathology. This system is a helpful resource for clinicians during the assessment and diagnostic process. The DSM is a compilation of classified disorders. Various criteria and symptoms must be present to warrant a diagnosis of a specific disorder. The diagnostic process with the guidance of the DSM is still a challenging endeavor. A clinician must complete a careful analysis before making a diagnosis. It is critical to consider and rule out other potential disorders and external factors that may be impacting the presenting behavior. This review will focus on a disorder presented in the DSM known as anorexia nervosa. It will include an appraisal of the history and current research associated with this disorder. This analysis will also provide a comprehensive review of the etiology and epidemiology of anorexia nervosa.

The American Psychiatric Association identifies three distinct types of eating disorders in the current Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) (American Psychiatric Association). The list includes anorexia nervosa, bulimia nervosa, and eating disorders not otherwise specified (NOS). Before exploring the nature of the development and treatment of the disease, it is important to highlight the process and challenge associated with diagnosing this disorder. Eating disorders are characterized by severe disturbances in eating behavior (Association 1994). Anorexia nervosa is an eating disorder specifically characterized by a refusal to maintain a minimally accepted body weight, an intense fear of weight gain, and a distorted body image. Typically, an anorexic presents at a weight distinctly below normal. However, it is critical to rule out the presence of other eating disorders, medical conditions, and external factors before diagnosing anorexia. Bulimia Nervosa must be ruled out before rendering a diagnosis of anorexia. Bulimia Nervosa is characterized by recurrent episodes of binge eating. Binge eating is described as the consumption of an abnormal amount of food in a discrete period of time. This period of consumption is followed by behavior designed to prevent weight gain such as self induced vomiting, fasting, and exercise. It is also important for a clinician to exclude the existence of any medical conditions that may be causing or contributing to severe weight loss prior to making a diagnosis. Finally, it is critical to explore external factors that may be contributing to the development of the disorder or to severe weight loss at a certain point in time. These factors can include death, divorce, unemployment, financial loss and major transitions. It is crucial to note the existence of these factors in order to gauge how these events impacted the severe weight loss and and/or the development of the disease. Diagnosing anorexia nervosa requires many important considerations. The development and treatment of anorexia is even more complex. The etiology and epidemiology of this disease can be influenced by a number of factors. According to existing research, there is no clear cut cause or treatment for anorexia nervosa. However, there is a myriad of research that emphasizes various dynamics that affect the development and treatment of this disease.

Anorexia nervosa has a surprisingly extensive history. The current and widespread focus on this disease in the media suggests that anorexia is a modern disorder. However, the medical community became conscious of this disease in the 1800’s. The symptom of intentional self-starvation has been reported since medieval Europe (Adams and Sutker 2001). During the Victorian era, women became increasingly aware of their food consumption. They feared food intake was perceived as a reflection of sexual appetite. Many women ate smaller amounts to display a modest sexual drive. Additionally, the Victorian society deemed food consumption by women as unfeminine. Some women refrained from eating to avoid bodily functions such as digestion and defecation. These functions were often considered unfeminine and undesirable (Brumberg 2000). The manifestation of the disease during this period is quite different then the progression of the disease today. However, the fear of weight gain is the common factor in all accounts of anorexia.

A staggering number of people develop eating disorders in this country. However, it is difficult to garner reliable statistics due to problems associated with data collection. The sampling and assessment methods used to collect data are not standardized or well tested. Research suggests that approximately eight million people in the United States suffer from eating disorders. Anorexia represents a substantial segment of this population. Anorexia nervosa tends to occur in pre and post pubescent young women. Fifteen percent of young women in the country display disordered eating patterns. Conservative numbers suggest that approximately one-half to one percent of females in the United States develop anorexia nervosa.

The statistics linked to the occurrence of anorexia suggest that a substantial number of young women have developed this disorder. The four criterion used to diagnose the disease are specific and standard: 1.) Refusal to maintain body weight at or above a minimally normal weight for age and height (e.g. weight loss leading to maintenance of body weight less than 85% of that expected; 2.) Intense fear of gaining weight or becoming fat 3.) Disturbance in the way in which 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 4.) In postmenarcheal females, amenorrhea, i.e. the absence of at least three consecutive menstrual cycles (Association 1994). Other potential signs of anorexia nervosa include a general preoccupation with food and weight.

Anorexia can cause serious and sometimes fatal medical complications if not successfully treated. Self starvation can cause damage to vital organs such as the heart, brain, and kidneys. Pulse rate and blood pressure may drop which can trigger irregular heart rhythms or heart failure. Nutritional deprivation can also instigate a deficit in bone calcium leaving bones susceptible to fragility and breakage. Anorexia can permanently damage reproductive organs, rendering reproduction impossible.

The development of anorexia nervosa is complex and varied. The etiology of the disease can be impacted by biological, societal, psychological, cultural, and familial factors.

The western culture greatly values thinness in young women. .Research identifies the media’s portrayal of super-slim women as more fashionable, desirable, and successful as one of the most influential socio-cultural factors contributing to anorexia (Gustafson, Popovich et al. 2001). However, not all young women exposed to cultural influences promoting thinness develop eating disorders. Therefore, other factors must contribute to the susceptibility of a particular individual to internalize these external messages. It is possible that an individual already obsessed with thinness may seek out media outlets geared towards this type of body image. These medium serve as an outlet for the existing pathology towards weight and shape. These particular individuals may pursue thinness as a way to solve problems (Polivy and Herman 2002).

Biological factors may contribute to the onset of anorexia nervosa. This perspective purports that certain genetic or biochemical conditions can increase the likelihood of developing the disorder. Serotonergic systems may play a role in the development of anorexia. These systems participate in the modulation of appetite, mood, and personality variables. Kaye, Gwirtsman, George, & Ebert (1991) found evidence of elevated cerebral spinal fluid 5-HIAA levels in long term weight restored anorexic patients (Adams and Sutker 2001). The CSF 5-HIAA levels are the major metabolite of brain serotonin. People with high serotonin levels tend to be obsessive, anxious, and perfectionists. Food contains a component of a protein that is necessary for the production of serotonin. Therefore, a reduction in food intake will decrease serotonin levels. This may reduce the undesirable symptoms associated with high serotonin levels, thus reinforcing the benefits of starvation (Brownlee 1999). It is difficult to identify increased serotonin levels as a clear cause of anorexia. An increase in serotonin levels can also be attributed to the impact of anorexia nervosa on the overall neuroendocrine system. The dilemma centers on whether the enhanced serotonin levels cause anorexia or are a result of anorexia. Prospective research would best reveal differential predictors of anorexia and avoid the contaminating influence of eating disorders on the predictor. However, this type of research is costly and invasive. Twin and family studies provide evidence for the genetic transmission of anorexia, although such evidence is not conclusive. Walters & Kendler (1995) found that the twin of a person with anorexia has a greater risk of developing anorexia nervosa relative to control subjects (Adams and Sutker 2001). However, it is difficult to distinguish between the influence of biological and environmental factors. Another biological factor that can contribute to the onset of anorexia nervosa is early puberty. A study conducted at Columbia University found that approximately three percent of the girls who developed early had eating disorders while less than one percent of normal or late developers had eating disorders. These young women may seek to control their weight in order to diminish the rate of puberty and/or to desexualize their developing bodies (Eller 1998).

Family dynamics have also been implicated in the perpetuation and development of eating disorders. Families may contribute to the preservation of anorexia by praising the associated weight loss and discipline used to achieve it. This dynamic often exists well after the anorexic becomes emaciated. Minuchin et al. (1978) characterized the families of anorexics as enmeshed, intrusive, hostile, and negating of the patient’s emotional needs (Polivy and Herman 2002). Haworth-Hoeppner (2000) found that anorexic patients who perceive family communication, parental caring and expectations as low as well as those that report physical or sexual abuse are at increased risk for developing anorexia. Research suggests that maternal invasion of privacy, jealousy, and competition can contribute to the onset of anorexia. Conversely, Strong & Huon (1998) found that perceived parental encouragement of autonomy is associated with less dieting behavior. Maternal influences are often a predictor of anorexia. Vanfurth et al. (1996) found that mothers’ critical comments prospectively predicted the development of anorexia for their daughters (Polivy and Herman 2002). It is difficult to assess the true maternal and familial influences on the development of anorexia. Most studies are correlational, making it difficult to determine if family dysfunction contributes to eating disorders or if eating disorders contribute to family dysfunction or both. Additionally, there is a lack of research involving control subjects. Case studies of eating disordered families are inconclusive without the presence of control families.

The influence of culture and race on the development of anorexia is uncertain. There is a prevailing belief that eating disorders occur less frequently in the African American population relative to the Caucasian population. Jones et al. (1980) found that most anorectic and bulimic patients were white and from upper socio-economic classes. Subsequent research by Rand and Kaldau (1992) found lower socio-economic status represented more in their study of eating disorders. Additionally, new research regarding the influence of race on the development of anorexia has emerged. Recent research suggests that the presence of anorexia in African American populations is similar to the occurrence of anorexia in Caucasian populations. Obtained and extrapolated prevalence rates among African American women are in very close range, albeit slightly lower than, those obtained with two or three comparative Caucasian samples (Mulholland and Mintz 2001). Mulholland & Mintz (2001) examined DSM-IV prevalence rates among African American college women. Prevalence rates were similar to those found among similar Caucasian samples (Mulholland and Mintz 2001). However, Rucker and Cash (1992) have found that black females hold more favorable body image attitudes than whites. There is a strong need for additional research specific to culturally diverse populations and eating disorders to further clarify the impact of race on the development of this disease. Minorities in western countries are reporting the incidence of anorexia more frequently. However the incidence of anorexia in these countries is considerably smaller than in the United States (Khandelwal, Shara et al. 1995). It is possible that the absence of social pressure for thinness may diminish the formation of the illness. The presentation of the disease in these countries is often quite distinct from the manifestation of anorexia in the United States. The focus of the disease is often on restriction rather than on the pursuit of thinness. Khandelwal et al. (1995) conducted research with patients of Indian origin. These patients reported a lack of concern regarding weight gain or body image. However, they demonstrated three cardinal features of the disease. These features included failure to eat, loss of weight, and amenorrhea. The absence of anxiety regarding weight gain or body image is peculiar. It might be explained by other cultural factors that may influence the development of anorexia. Fasting for spiritual reasons or dietary changes motivated by eccentric nutritional ideas are cultural factors that may influence a reduction in food consumption. Further research is needed to uncover more information regarding the influence of culture and race on the development of anorexia.

Personality disorders are often invoked to account for the perplexing syndrome of anorexia nervosa. Most contemporary clinicians attribute a consistent cluster of personality traits evident in young women as a contributing factor to the development of anorexia. These distinguishing personality qualities include hyperactivity, alertness, rigidity, ambition, oversensitivity, insecurity and hyperconscientiousness. Additionally, an anorexic is often characterized by neatness, meticulosity, stubbornness, and perfectionism. She or he is also introverted, serious, self-willed, and lacking in the warmth and spontaneity that is consistent with her years. The remarkable uniformity of clinical observations regarding anorexic personality features is matched by the extraordinary lack of consensus concerning the interpretation of their etiological significance. Personality disorders in clinical anorexia nervosa samples are estimated to occur in twenty three to eighty percent of a given sample. Several studies report a high prevalence of avoidant personality disorder and obsessive-compulsive personality disorder in anorexia samples (Nilsson, Gillberg et al. 1999). Rastam, (1992) showed premorbid obsessiveness in a study of teenage-onset anorexia. In a six year follow up study, the group exhibited traits of obsessive personality disorder and social avoidance after recovering from anorexia. Personality disorders are significantly overrepresented in anorexia subjects after onset and weight restoration. Investigators have examined patterns of comorbidity among persons diagnosed with anorexia nervosa in order to determine possible etiological mechanisms. Affective disorders, anxiety disorders, and personality disorders have received the greatest amount of attention from researchers. The most prevalent anxiety diagnoses are obsessive compulsive disorder and social phobia. Rothenberg (1990) reported that between eleven and eighty-three percent of patients displayed obsessive symptoms during the acute phase of anorexia or after weight restoration. Rastam (1992) found a strong association between anorexia nervosa and premorbid obsessional characteristics. Sixty percent of the anorexics versus eighteen percent of the control subjects had pronounced obsessional traits. However, an additional twenty-five percent of anorexic subjects were judged to have acquired obsessional characteristics after the development of anorexia. It is difficult to determine if certain characteristics make one vulnerable to the development of anorexia or if those characteristics develop as a result of anorexia (Vitousek and Manke 1994). Therefore, the prevalence of personality disorders amongst anorexics is uncertain. Demarcation of personality attributes is confounded by the impact of self starvation on personality features. Additionally, it appears that depression is the most widely reported comorbid feature of anorexia. Prevalence rates range from twenty-one to ninety-one percent amongst anorexics (Adams and Sutker 2001).

The etiology of anorexia nervosa is complex. There are a number of factors that may contribute to the development of the disease. However, there is no single or consistent cause of anorexia that is present in every manifestation of the disease. Similarly, the epidemiology of anorexia is multifaceted. Many factors influence the efficacy of a particular treatment plan. These factors include premorbid and comorbid personality disorders, familial involvement and support, the severity of the disease, age and willingness of the patient.

Recovery from anorexia nervosa is an arduous and often lengthy process. Strober, Freeman, and Morrell (1997) assessed the long term course of recovery and relapse amongst a group of anorexic patients over a fifteen year period. Results indicated that approximately thirty percent of patients experienced a relapse in anorexic symptoms before recovery and nearly seventy-six percent of the sample met criteria for full recovery. However the length of recovery was protracted and ranged from fifty-seven to seventy-nine months. Steinhausen (1995) calculated the means for recovery across studies and revealed that approximately forty percent of anorexic patients recover, thirty percent improve, and twenty percent exhibit a chronic course of the disease (Adams and Sutker 2001).

It is critical to develop a treatment plan that provides the appropriate level of care for each patient. Potential levels of care include inpatient hospitalization, partial day hospitalization, intensive outpatient treatment, and outpatient treatment. The primary goals of inpatient treatment are achieving medical stabilization, establishing regular patterns of eating, identifying issues that contribute to current disturbances with eating, addressing body image distortions, and developing a relapse prevention plan. The first objective is the restoration of physical health through caloric intake. This is achieved by developing structured meal plans to achieve a slow and steady weight gain. If this approach is unsuccessful, intravenous feeding may be administered to sustain the patient until voluntary food consumption can be achieved. Once the patient is able to voluntarily eat, behavioral approaches are often used to enhance nutritional status and eating habits. Behavior is altered by active meal planning, behavioral contracting, and education about myths associated with nutrition. A nutritionist and clinical team often direct the meal planning activities until the patient can independently develop and follow a sensible food plan. As previously noted, the primary motivation for anorexic behavior is the fear of weight gain. A behavioral approach known as exposure with response prevention is often employed to address the intense anxiety associated with weight gain. The patient is exposed to the feared stimulus, food, and is prevented from engaging in anxiety reducing activities such as starvation and exercise. Continuous exposure to the stimulus during which the feared negative consequences (i.e. excessive weight gain, rejection, self-loathing) do not occur can alleviate dysfunctional beliefs about eating and weight gain. The patient is supported during this anxiety provoking time by individual and group therapy designed to focus on the issues underneath the fear associated with weight gain. This process usually continues throughout the recovery and maintenance process. Partial day hospitalization occurs after the patient is medically stabilized and can safely be reduced to a lower level of care. In this setting, the patient attends hospital treatment groups during the day and is supervised for all meals. Intensive outpatient therapy is an even lower level of care that requires the patient to attend a certain number of treatment groups and supervised meals per week. Outpatient therapy comprises the majority of treatment due to the often severe limitations of insurance coverage. In this setting, patients continue to focus on psychological issues that contribute to anorexic behaviors and distorted body image. Additionally, patients remain focused on addressing dysfunctional eating habits and learning new approaches to health and nutrition.

There are various therapy techniques that have proven to be valuable during the recovery process. Body image therapy is frequently utilized during the course of treatment. As a patient gains weight, body size distortion and dissatisfaction is likely to intensify. Body image therapy assists the patient in addressing these distortions and uncovering the feelings behind these false beliefs. Family therapy is often a critical component in the treatment of anorexia. Regardless of orientation, the therapy typically focuses on family communication patterns, the role of anorexia nervosa in the family network, and the nature of specific relationships within the family system. Retrospective research has confirmed the effectiveness of family therapy in the treatment of this disease. Robin, Bedway, Siegel, & Gilroy (1996) empirically validated their behavioral family systems treatment protocol for treating adolescent anorexic patients (Adams and Sutker 2001). The benefit of pharmacological treatment in the recovery process is unclear. Research indicates that the core psychopathology of anorexia nervosa remains relatively refractory to pharmacological treatment (Adams and Sutker 2001). Anti-anxiety medications are sometimes used to diminish distress related to food consumption and weight gain (Steiner and Lock 1998). However, these medications do not seem to assist in the treatment of the actual disorder. Systematic studies that explore the use of medication with adolescent anorexics are critical to clearly understand the implications of pharmacological intervention.

The cause and treatment of anorexia nervosa is complex. There appears to be a multitude of factors that can influence the development of the disease as well as the recovery from the disease. As a result of the number of conditions that can impact this disease, it seems that a systems approach to intervention and treatment is most beneficial. The first signs of anorexia should be treated with individual and family therapy. Group therapy can also be employed to discuss and rethink misperceptions about body image. A pharmacological referral may be beneficial if the patient presents with a comorbid condition. It is clear that more research is warranted to uncover the impact of biological, societal, familial, cultural, and psychological factors on the etiology and epidemiology of this disease.

References

Adams, H. E. and P. B. Sutker (2001). Comprehensive Handbook of Psychopathology. New York, New York, Plenum Publishers.

Association, A. P. (1994). Diagnostic and Statistical Manual of Mental Disorders. Washington D.C., American Psychiatric Association.

Brownlee, S. (1999). Anorexia's roots in the brain. US News & World Report. 127: 52-53.

Brumberg, J. J. (2000). Fasting Girls: The History of Anorexia. New York, Vintage Books.

Dawson, G. C. and J. M. Neale (1994). Abnormal Psychology. New York, Wiley.

Eller, D. (1998). Detecting Eating Disorders. Parents. 73: 115-116.

Gustafson, R., M. Popovich, et al. (2001). Subtle ad images threaten girls more. Marketing News. 35: 12-13.

Khandelwal, S. K., P. Shara, et al. (1995). "Eating Disorders: an Indian perspective." The International Journal of Social Psychiatry 41: 132-146.

Mulholland, A. M. and L. B. Mintz (2001). "Prevalence of Eating Disorders Among African American Women." Journal of Counseling Psychology 48(1): 111-116.

Nilsson, E. W., C. Gillberg, et al. (1999). "Ten Year follow-up of adolescent onset anorexia nervosa:personality disorders." Journal of the Academy of Child and Adolescent Psychiatry 38(11): 1389-95.

Polivy, J. and P. C. Herman (2002). Causes of Eating Disorders. Annual Review of Psychology. 53: 187-213.

Steiner, H. and J. Lock (1998). "Anorexia nervosa and bulimia nervosa in children and adolescents: a review of the past ten years." Journal of the American Academy of Child and Adolescent Psychiatry 37(4): 352-359.

Vitousek, K. and F. Manke (1994). "Personality Variables and Disorders in Anorexia Nervosa and Bulimia Nervosa." Journal of Abnormal Psychology 103(1): 137-147.