Eating disorders (EDs), namely Anorexia Nervosa (AN) and Bulimia Nervosa (BN), are serious psychiatric conditions characterized by severe disturbances in eating behaviors, weight regulation, and associated psychopathology. These disorders carry high rates of morbidity and mortality, necessitating immediate and specialized professional intervention. Understanding the multifaceted etiology, the constellation of clinical features, and the evidence-based management strategies is crucial for effective diagnosis and treatment.
Anorexia Nervosa (AN)
Anorexia Nervosa is defined by a persistent restriction of energy intake leading to a significantly low body weight (BMI less than 17.5 kg/m² or below the minimally normal weight for age and height), an intense fear of gaining weight, and a disturbance in the way one’s body shape or weight is experienced.
A. Etiology of Anorexia Nervosa
AN is understood through a biopsychosocial model, where no single cause is sufficient, but rather a complex interplay of vulnerability factors.
- Biological and Genetic Factors: There is a significant genetic component, with heritability estimates ranging from 50% to 70%. Neurobiological research suggests abnormalities in neural circuits involved in reward, appetite regulation, and cognitive control. Dysfunctions in neurotransmitter systems, particularly serotonin and dopamine, are implicated, potentially contributing to rigidity, perfectionism, and anxiety often observed before the onset of the disorder.
- Psychological Factors: Individuals often exhibit perfectionism, obsessive-compulsive traits, emotional constraint, and heightened anxiety. Cognitive rigidity and difficulties in set-shifting (the ability to switch between tasks or thoughts) are frequently observed, impeding recovery efforts.
- Environmental Factors: Early childhood trauma, family dynamics focused on achievement, and critical comments about weight or shape contribute to vulnerability.
B. Precipitating Factors
These are acute stressors or life events that trigger the onset of the disorder in a vulnerable individual.
- Dieting and Weight Loss: The initiation of a restrictive diet, often intended for minor weight loss, is the most common precipitant. The initial success may be positively reinforced, increasing rigidity.
- Life Transitions and Stress: Major life changes (e.g., starting college, moving homes, puberty) can create anxiety and a perceived loss of control, leading individuals to use eating behaviors as a coping mechanism to restore perceived mastery.
- Socio-Cultural Pressure: Exposure to media emphasizing thinness (the “thin ideal”) and participation in weight-sensitive activities (e.g., ballet, modeling, competitive sports) significantly increase risk.
C. Clinical Features
AN presents in two primary subtypes: the Restricting Type (weight loss achieved solely through dieting, fasting, or excessive exercise) and the Binge-Eating/Purging Type (recurrent binge eating or purging behavior during the episode).
| Category | Features |
|---|---|
| Physical (Medical) | Severe underweight, bradycardia (slow heart rate), hypothermia, hypotension, amenorrhea (in post-menarchal females), lanugo (fine body hair), dry skin, osteopenia or osteoporosis, and severe electrolyte disturbances (especially in the purging type). |
| Behavioral | Excessive exercise, strict food rules, ritualistic eating, social withdrawal, denial of illness, hiding food, and resistance to weight gain. |
| Psychological | Distorted body image, intense fear of fatness, preoccupation with food, body checking, high comorbidity with anxiety (especially OCD) and depression. |
D. Management of Anorexia Nervosa
Management requires a multidisciplinary team approach involving physicians, dietitians, and mental health professionals, focused primarily on weight restoration and psychosocial intervention.
- Medical Stabilization: This is the immediate priority. Hospitalization is required for severe bradycardia, profound weight loss (e.g., BMI < 15), or acute risk of suicide. Careful monitoring for refeeding syndrome (potentially fatal shifts in fluids and electrolytes that can occur in malnourished patients initiating refeeding) is critical.
- Nutritional Rehabilitation: Involves restoring weight to a medically healthy range. This is achieved through structured meal plans designed to promote consistent, gradual weight gain (1–3 lbs/week in inpatient settings).
- Psychological Treatment:
- Family-Based Treatment (FBT/Maudsley Model): The first-line treatment for adolescents, FBT empowers parents to take charge of nutritional rehabilitation until the patient can resume autonomous eating.
- Enhanced Cognitive Behavioral Therapy (CBT-E): An evidence-based treatment for adult AN, focusing on changing the cognitions and behaviors that maintain the disorder, particularly body image concerns and restrictive eating.
- Pharmacological Agents: Medications (antidepressants, antipsychotics) are generally ineffective for core AN symptoms but may be used to treat co-occurring depression or anxiety once the patient is weight-restored.
Bulimia Nervosa (BN)
Bulimia Nervosa is characterized by recurrent episodes of binge eating (eating a large amount of food in a discrete period with a sense of lack of control) followed by inappropriate compensatory behaviors (purging, fasting, excessive exercise) to prevent weight gain. Unlike AN, patients with BN are typically within or above the normal weight range.
A. Etiology of Bulimia Nervosa
The etiology of BN overlaps with AN but often emphasizes affective and impulse control factors.
- Neurobiological Factors: Evidence suggests dysregulation in the serotonin system, which impacts satiety, mood, and impulse control. Dopaminergic pathways related to reward sensitivity may also predispose individuals to the addictive cycle of binging and purging.
- Temperamental Factors: High levels of emotional instability, impulsivity, and affective dysregulation are common precursors. BN patients frequently struggle with self-criticism and low self-esteem, which the binge-purge cycle temporarily attempts to soothe.
- Environmental and Interpersonal Factors: A history of dieting is nearly universal among BN patients. Chronic dieting leads to biological and psychological deprivation, lowering the threshold for binge eating. Interpersonal difficulties, such as conflict or rejection, often serve as proximal triggers for a binge episode.
B. Precipitating Factors
The cyclical nature of BN often arises from emotional and environmental triggers that disrupt emotional balance.
- Affective Dysregulation: Negative emotional states (e.g., anger, sadness, boredom) are the most common trigger for a binge episode, functioning as a maladaptive form of self-soothing or emotional avoidance.
- Interpersonal Stress: Conflicts or perceived failures in relationships can lead to immediate body image concerns and subsequent compensatory behaviors.
- Strict Dieting Rules: Breaking an overly strict dietary rule (the “all-or-nothing” mentality) often leads to a feeling of loss of control, resulting in a full-blown binge (the abstinence violation effect).
C. Clinical Features
The hallmark of BN involves the secretive cycle of binging and compensating, occurring at least once a week for three months.
| Category | Features |
|---|---|
| Physical (Medical) | Electrolyte disturbances (hypokalemia from vomiting), fluid retention, dental erosion (Perimylolysis), Russell’s sign (calluses/scars on knuckles from self-induced vomiting), parotid gland swelling (“chipmunk cheeks”), esophageal tears, and bowel damage from laxative abuse. |
| Behavioral | Hoarding food, eating in secret, frequent visits to the restroom after meals, excessive focus on body weight and shape, and difficulty maintaining structured routines. |
| Psychological | Marked shame, self-disgust, depressive symptoms, significant anxiety focused on weight/shape, co-occurring substance use, impulsivity, and difficulty identifying and managing emotions. |
D. Management of Bulimia Nervosa
The immediate objective of BN management is to interrupt the binge-purge cycle, stabilize nutritional intake, and address the underlying cognitive distortions and emotional regulation deficits.
- Psychological Treatment (First-Line):
- Cognitive Behavioral Therapy (CBT): Highly effective and the gold standard for BN. CBT-E specifically targets the core psychopathology of EDs, normalizing eating patterns and challenging the overvaluation of weight and shape.
- Dialectical Behavior Therapy (DBT): Useful for patients exhibiting high levels of emotion dysregulation, impulsivity, and co-occurring Borderline Personality Disorder features.
- Pharmacological Agents: Selective serotonin reuptake inhibitors (SSRIs), particularly fluoxetine (Prozac), are the most effective pharmacological treatment for BN. Fluoxetine is often prescribed at higher doses than those used for depression (e.g., 60 mg/day) and helps reduce the frequency of binge and purge episodes, often in conjunction with psychotherapy.
- Nutritional Counseling: Focuses on establishing a regular eating pattern, reducing dietary restriction, and normalizing the relationship with food to prevent the vulnerability to binge eating.
Conclusion
Anorexia Nervosa and Bulimia Nervosa are complex, multifaceted disorders requiring specialized, evidence-based care delivered by integrated multidisciplinary teams. While AN requires immediate medical stabilization due to its profound physical consequences stemming from starvation, BN demands intensive focus on psychological intervention to dismantle the binge-purge cycle and address severe emotional dysregulation and cognitive distortions. Successful long-term recovery depends on comprehensive treatment that addresses biological vulnerability, psychological triggers, and environmental maintenance factors.
References
American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Arlington, VA: American Psychiatric Publishing.
Fairburn, C. G. (2008). Cognitive behavior therapy and eating disorders. Guilford Press.
Keel, P. K., & Haedt, A. A. (2009). Thirty years of research on bulimia nervosa: What have we learned and where are we going? Clinical Psychology Review, 29(4), 86-97.
Lock, J., & Le Grange, D. (2015). Treatment manual for anorexia nervosa: A family-based approach (3rd ed.). Guilford Press.
Walsh, B. T. (2016). The use of psychotropic medication in anorexia nervosa. The International Journal of Eating Disorders, 49(5), 452–456.
