According to the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV), eating disorders can be classified as anorexia nervosa (AN), bulimia nervosa (BN), and eating disorder not otherwise specified (ED-NOS). BN is characterized by recurrent episodes of “out of control” or binge eating, occurring on average at least twice a week for 3 months with self-evaluation that is unduly influenced by body shape and weight. Unlike AN, BN patients are typically within the normal weight range or mildly overweight. Although not during a binge, they do restrict their total caloric consumption between binges.
The onset of Bulimia Nervosa is usually in adolescence but may be as late as early adulthood. Estimates of lifetime prevalence among women range from 1.1% to 4.2%, with the male-to-female ratio ranging from 1:6 to 1:10. Eating disorders are more frequent in industrialized societies. In the United States, among non-Caucasian races, African American women are more likely to develop BN as compared to AN and more likely to purge. Biological and psychosocial factors are implicated in the pathophysiology but only partially understood. Increased endorphin levels are found in patients with Bulimia Nervosa after purging and may be likely to induce feelings of wellbeing. Antidepressants often benefit patients with Bulimia Nervosa and suggest a role for serotonin and norepinephrine. First-degree female relatives and monozygotic twins of patients with anorexia nervosa have higher rates of AN and BN. Families of patients with Bulimia Nervosa have higher rates of substance abuse, particularly alcoholism, affective disorders, and obesity. High levels of hostility, chaos, and isolation and low levels of nurturance and empathy are reported in families of children presenting with eating disorders.
The essential features of Bulimia Nervosa are binge eating and inappropriate compensatory behaviors including fasting, vomiting, laxative use, or exercising to prevent weight gain. Binge eating is typically triggered by dysphoric mood states, interpersonal stressors, intense hunger following dietary restraints, or negative feelings related to body weight, shape, and food. Individuals are typically ashamed of their eating problems and binge eating usually occurs in secrecy. In addition to DSM-IV criteria, the Eating Attitudes Test, Eating Disorders Inventory, or Body Shape Questionnaire may be helpful in diagnosis and assessment of eating disorders. Comorbid conditions include major depressive disorder or dysthymia, bipolar disorder, obsessive-compulsive disorder, sexual abuse, and substance abuse. Patients with BN have been described as having difficulties with impulse regulation. Medical complications are related to obesity, vomiting, and laxative abuse. Differential diagnoses include medical conditions like abdominal epilepsy, brain tumors, Kluver-Bucy syndrome and Klein-Levin syndrome.
The recommended treatment plan combines both psychotherapy and medications. Antidepressants are used to reduce the frequency of disturbed eating behaviors and to treat any comorbid depression, anxiety, obsessive-compulsive features, and symptoms of impulse disorders. The only medication approved by the Food and Drug Administration (FDA) for Bulimia Nervosa is the serotonin-reuptake inhibitor fluoxetine (Prozac). Several studies have demonstrated efficacy of other serotonin-reuptake inhibitors like fluoxetine, sertraline, paroxetine, and citalopram; tricyclic antidepressants (TCA) like imipramine, nortriptyline, and desipramine; and monoamine oxidase inhibitors (MAOI). Doses of TCA and MAOI antidepressants parallel those used to treat depression, but higher doses of fluoxetine (60-80 mg/day) may be needed to treat BN. Bupropion has been associated with seizures in purging bulimic patients and its use is not recommended. Lithium continues to be used occasionally as an adjunct for comorbid disorders.
Little long-term follow-up data on Bulimia Nervosa exist. Shortterm success is 50-70%, with relapse rates between 30% and 50% after 6 months but the overall prognosis is better than that for patients with AN. Poor prognostic factors are hospitalization, higher frequency of vomiting, poor social and occupational functioning, poor motivation for recovery, severity of purging and presence of medical complications, high levels of impulsivity, longer duration of illness, delayed treatment, and a premorbid history of obesity and substance abuse.