State of the Art: The Therapeutic Approaches to Bulimia Nervosa

Abstract

Purpose:

Bulimia nervosa (BN) is an eating disorder characterized by binge eating, inappropriate compensatory behaviors, and body image concerns in persons at or above a healthy body weight. BN is a serious disorder with medical sequelae and marked psychosocial impairment. To reduce and eliminate symptoms of BN, psychological and pharmacological treatments for BN have been developed. Here, we review the current state-of-the-art treatments for BN.

Methods:

We conducted a narrative review of the BN treatment literature to synthesize the current evidence base, provide recommendations, and propose future directions for BN treatment research.

Findings:

At present, the first-line, state-of-the-art treatment for adults with BN is cognitive-behavioral therapy (CBT). Interpersonal therapy is a second-line evidence-based treatment for adults with BN, and dialectical behavior therapy and integrative cognitive-affective therapy show initial promise. For adolescent BN, family-based treatment for BN or CBT are evidence-based approaches. Pharmacotherapy is best considered adjunctive to psychotherapy in adults with BN, but may be helpful depending on the type of psychotherapy and whether psychotherapy is ineffective or unavailable. Fluoxetine 60 mg/day is the medication of choice for adults with BN. Little is known with respect to pharmacological treatment of adolescent BN, though fluoxetine 60 mg/day holds promise.

Implications:

Despite decades of treatment-development research in BN, there is room for improvement, as nearly 60% of those with BN do not achieve remission with specialty treatment, and strikingly few randomized-controlled trials for adolescent BN exist. Moreover, the field should address issues related to treatment dissemination, access, and cost.

Bulimia nervosa (BN) is an eating disorder characterized by recurrent binge eating, inappropriate compensatory behavior, and body image concern in persons who are at or above a healthy body weight¹. BN is associated with functional impairment, medical and psychiatric comorbidities². Lifetime prevalence of BN is approximately 0.5% among women³, and the disorder typically onsets in late adolescence^4,5. To reduce the symptoms of BN, psychotherapies and pharmacotherapies have been developed for tested in adults with the disorder. Despite the fact that BN typically begins in late adolescence, few treatments been developed and evaluated for adolescent BN. Here, we describe the current evidence-based psychotherapeutic and pharmacologic approaches to the treatment of BN. We synthesize the current literature, provide recommendations, and highlight areas for future study.

Psychotherapeutic Approaches

Psychotherapies for Adults

Dozens of randomized-controlled trials of psychotherapies have been conducted for adults with BN. Here, we detail the psychotherapeutic approaches with the greatest evidence base for adults with BN.

Cognitive-Behavioral Therapy

Cognitive-behavioral therapy for BN (CBT-BN) is a brief, present-oriented approach that is the treatment of choice for BN^6,7. The cognitive-behavioral model of BN provides the theoretical framework for CBT-BN⁸ and has been supported by empirical research⁹. This model hypothesizes that dieting begins as a consequence of body shape and weight concerns. Dieting eventually leads to binge eating, which, in turn, prompts engagement in inappropriate compensatory behaviors (e.g., self-induced vomiting, laxative and/or diuretic misuse, excessive exercise, etc.), reinforces body image concerns, and renews dieting attempts. Thus, the cognitive-behavioral model of BN hypothesizes that weight and shape concerns and eating disorder behaviors are mutually reinforcing and perpetuate a vicious cycle that maintains BN.

CBT-BN uses a staged approach to introduce behavioral techniques and cognitive strategies to target symptoms delineated in the cognitive-behavioral model of BN. The treatment is delivered in about 20 sessions over approximately six months. The initial focus of CBT-BN is behavioral, as the clinician helps the patient regulate eating patterns and self-weighing behavior. Following management of eating disorder behaviors, the focus of CBT-BN pivots toward cognitive restructuring to address shape and weight concerns. An enhanced form of CBT (CBT-E) was later developed for the transdiagnostic treatment of eating disorders, including BN⁶. A focused form and a broad form of CBT-E exist. The focused form is very similar to CBT; however, the broad form incorporates additional, optional modules to address problems associated with eating disorders, including perfectionism, low self-esteem, mood intolerance, and interpersonal stress.

An individualized formulation is a foundational component of CBT-BN and is completed in or prior to the first treatment session. The formulation is a collaboration between the clinician and patient in which the patient’s eating disorder behaviors and thoughts are visually diagramed. For example, the clinician may begin the formulation by asking the patient to identify precipitants of binge eating, and the formulation is expanded from this starting point. One goal of the formulation is to increase the patient’s awareness of the factors that maintain their disorder. Another goal is to help the patient to understand the rationale behind targeting behaviors and thoughts in CBT-BN; thus, the formulation may promote patient “buy-in.” The formulation is meant to be revisited and modified throughout treatment.

Self-monitoring is prescribed in the first session of CBT-BN and is a cornerstone of the treatment. Patients are asked to keep daily logs of food and drink and contextual factors (e.g., time, place, thoughts, emotions) around consumption. Patients are also asked to indicate the presence of binge eating and inappropriate compensatory behaviors. The purpose of self-monitoring is to help the patient increase awareness of eating behaviors, as well as cognitive and emotional antecedents and consequences of eating behaviors. The clinician assesses the patient’s prior experiences with self-monitoring and highlights that the purpose of self-monitoring in CBT-BN is not to count calories and/or macronutrients – as patients may have done in the past – but to collect data and to help generate hypotheses about factors that maintain BN. Self-monitoring logs are reviewed in detail at the beginning of each treatment session; thus, it is important for the patient to regularly complete logs. Self-monitoring may be completed with paper-and-pencil logs, smartphone applications (“apps”), or websites. The clinician should assess patient concerns around and/or resistance to self-monitoring that may interfere with completion of logs. Common concerns about self-monitoring include shame around logging binge episodes, inconvenience, and forgetfulness. Supporting the patient in problem solving ways to successfully and regularly complete self-monitoring logs is important, as self-monitoring continues throughout CBT-BN.

Once-weekly weighing with the clinician is instituted in the first session of CBT-BN and continues throughout treatment. Patients often desire to weigh themselves more frequently; however, the clinician provides psychoeducation that more frequent weighing will capture fluctuations in weight that are physiologically not meaningful and will contribute to worry about body weight and shape. Following in-session weighing, the clinician informs the patient of their weight and plots the patient’s weight over time to establish a trend. Alongside this prescription of once-weekly weighing, the clinician provides psychoeducation around typical weight fluctuations and the relative ineffectiveness of weight control behaviors, like self-induced vomiting. There are several purposes of once-weekly weighing. One purpose is to encourage healthy self-weighing behaviors in patients with BN; individuals with BN may compulsively self-weigh or may habitually avoid self-weighing. Another purpose is to track how the patient’s weight fluctuates with treatment and the prescription of regular eating (described in the following paragraph). Clinicians may discuss with patients that a goal weight is one that does not necessitate dietary restriction or use of other compensatory behaviors.

Once the patient has demonstrated regular self-monitoring, the clinician prescribes regular eating, which typically consists of three meals and two to three snacks per day and going no more than four hours without eating. Patients are encouraged to plan ahead what and when they will eat. If a patient deviates from their plan by over- or under-eating, the clinician encourages them to return to the plan with the next meal or snack, rather than attempting to compensate via restriction. At this stage, the clinician may also introduce strategies for helping the patient to prevent binge eating and compensatory behaviors, such as stimulus control or engagement in alternative behaviors that are incompatible with binge eating and purging, like taking a bath.

With successful implementation of behavioral techniques and management of eating disorder behaviors, CBT-BN shifts to target cognitive distortions theorized to underpin BN. Cognitive distortions related to eating behaviors and food rules are first targeted; self-monitoring forms may provide clues to target distortions. One strategy may be to consume foods in-session that the patient believes will make them fat. A second step is identifying triggers and targeting behaviors that lead to body image concerns, such as body checking and comparisons to others. Patients are encouraged to increase participation in activities that are not eating disorder-related to expand self-evaluation into other domains and decrease the impact of body weight and shape on self-worth. If the clinician is practicing broad CBT-E, the clinician may elect to include optional modules, such as mood intolerance and interpersonal difficulties, at this phase.

CBT-BN concludes with a discussion of progress, realistic expectations with respect to continued progress, relapse prevention, and planning ahead. In this discussion, the clinician helps the patient to identify: (1) strategies they will continue to use to minimize the likelihood of a relapse, (2) warning signs of a relapse, and (3) plans to address a relapse. The clinician may help the patient to create a coping card that details a plan to address a relapse of eating disorder behaviors and thoughts.

The evidence for CBT-BN is robust. For instance, recent meta-analyses of randomized-controlled trials for BN treatment found that therapist-led CBT-BN was more significantly efficacious than inactive comparisons (i.e., no treatment, waitlist control) ^10,11, and other active psychotherapies (e.g., Interpersonal Therapy, supportive psychotherapy)^10,12, but not pharmacotherapy, in promoting abstinence of symptoms at end-of-treatment. These meta-analyses also suggested that self-help CBT-BN was significantly more efficacious than inactive comparisons (such as being assigned to a waiting list) in promoting abstinence of symptoms at end-of-treatment^10,11. Current clinical guidelines recommend the use of therapist-led CBT as first-line treatments for BN, but highlight that guided self-help CBT is cost effective and may be useful when specialized eating disorder services are not available⁷.

There is yet limited evidence with respect to whether CBT-E is superior to CBT-BN. One trial randomized individuals with BN and comorbid borderline personality disorder to broad CBT-E or focused CBT-E (similar to CBT-BN), and found no statistically significant differences in abstinence of symptoms at end-of-treatment and six-month follow-up¹³. However, moderator analysis suggested that those with greater affective/interpersonal problems fared better with CBT-E broad form versus CBT-E focused form. Thus, CBT-E broad form may be indicated when elevated affective comorbidity is present.

Interpersonal Therapy

Interpersonal Therapy (IPT) is a brief treatment that links interpersonal difficulties and social skills deficits to eating disorder symptoms¹⁴. IPT was initially developed for the treatment of depression¹⁵ and was adapted for the treatment of BN due to links between interpersonal functioning and bulimic behaviors^14,16. The interpersonal theory of binge eating provides the theoretic framework for IPT¹⁷. This model posits that interpersonal difficulties give rise to low self-esteem and negative affect, which, in turn, lead to eating disorder behaviors. Engagement in eating disorder behaviors may further contribute to interpersonal difficulties, thereby maintaining BN.

IPT for BN is typically delivered in six to 20 sessions over three phases and focuses on addressing interpersonal problems as an indirect means to reduce eating disorder symptoms. In the initial phase of IPT, the patient’s eating disorder symptoms and interpersonal problem areas are assessed. The clinician provides the patient with a formal eating disorder diagnosis and psychoeducation about BN. The clinician assigns the patient to the “sick role,” in which the clinician emphasizes that the patient is ill with BN and stresses the importance of focusing on treatment and recovery from BN, as would happen with a medical illness. At the same time, the clinician instills hope that IPT can help to reduce or eliminate BN symptoms.

Interpersonal problems are assessed using an interpersonal inventory, a cornerstone of IPT. The interpersonal inventory determines the interpersonal problem area that will be the focus of treatment and connects interpersonal problems to eating disorder symptoms. Interpersonal problem areas include interpersonal deficits, role transitions, role disputes, and grief. Interpersonal deficits are characterized by longstanding difficulties with making and maintaining friendships. Role transitions are major life transitions that affect interpersonal relationships, such as graduating from school, becoming a parent, or starting a new job. Role disputes are characterized by discrepant expectations about the role someone plays in a relationship, and often result in disagreement. Grief involves the loss of someone significant to the patient. The interpersonal assessment is also used to collaboratively develop an interpersonal case formulation that links interpersonal problem areas to the onset and maintenance of the eating disorder. The interpersonal case formulation pinpoints which problem area will be the focus of treatment; one problem area is selected as a treatment target, even though a patient may have difficulties in two or more areas.

In the intermediate phase of IPT, the clinician helps the patient work toward interpersonal goals and keeps the patient focused on the interpersonal problem area. Techniques to address interpersonal problem areas include communication analysis, role playing, and clinician modeling of good verbal and non-verbal communication. The patient also completes weekly eating disorder symptom assessments and the clinician repeatedly connects eating disorder behaviors to interpersonal problem areas, which reinforces the importance of addressing interpersonal problem to reduce eating disorder symptoms. Clinicians also connect reductions in eating disorder behaviors to improvements in interpersonal problem areas. IPT concludes with a termination phase in which the clinician and patient review the patient’s progress, discuss remaining interpersonal work, and identify potential warning signs and relapse prevention strategies.

IPT is an efficacious treatment for BN, as evidenced by results from two randomized-controlled trials. One trial randomized 220 adults with BN to IPT or CBT, and found that CBT was statistically superior to IPT with respect to end-of-treatment abstinence from eating disorder behaviors (CBT-BN 29% vs. IPT 6%)¹⁸. Similarly, another trial that randomized 75 women to receive CBT, IPT, or behavior therapy, and found that CBT was superior to IPT in facilitating end-of-treatment symptom reductions¹⁶. However, both of these trials found no statistically significant differences in those who received IPT versus CBT at one-year follow-up^18,19. Thus, it seems that IPT may have a slower effect on reducing eating disorder symptoms than CBT, perhaps by virtue of its indirect treatment of the eating disorder via interpersonal behaviors. Together, data suggest that IPT is an efficacious second-line treatment for BN.

Dialectical Behavior Therapy

Dialectical Behavior Therapy (DBT) for BN is a present-focused approach that enhances skills in interpersonal effectiveness, distress tolerance, emotion regulation, and mindfulness domains to reduce affective lability and eating disorder behaviors²⁰. DBT for BN is rooted in the biopsychosocial theory, which hypothesizes that the combination of an individual’s biological temperament and an invalidating environment give rise to affective lability that triggers eating disorder symptoms²¹. DBT was originally developed for individuals with chronic suicidality²², and was adapted for BN based on evidence that emotion dysregulation triggers eating disorder behaviors and vice versa^23,24.

DBT is a structured treatment that is comprised of individual therapy, coaching calls (described below), a skills group, and a consultation group for DBT clinicians (described below); DBT for BN may not include some components of traditional DBT treatment. Individual therapy helps patients to apply skills to certain targets, which are addressed in order of importance as established by the DBT model. Level one targets are life-threatening behaviors (e.g., non-suicidal self-injury, purging with syrup of ipecac or insulin omission by persons with insulin-dependent diabetes), level two targets are therapy-interfering behaviors (e.g., not completing diary cards, arriving late to session), and level three targets are those that interfere with quality of life (e.g., eating disorder behaviors). Outside of sessions, patients are encouraged to use brief, skills-focused coaching calls to connect with a clinician and receive help in applying skills to challenging real-world situations, such as when urges to binge eat or purge are high. Groups teach interpersonal effectiveness, distress tolerance, emotion regulation, and mindfulness skills in a didactic format to individuals participating in DBT. Finally, DBT clinicians participate in weekly consultation groups to promote adherence to the DBT model through practicing skills and reviewing the DBT manual. Additionally, consultation groups are used to provide group supervision. Clinician consultation groups promote adherence to the DBT model and assist with burnout.

DBT for BN commences with commitment and orientation, in which the patient commits to ceasing bulimic behaviors. Following commitment, DBT uses skills, diary cards, and behavior chain analyses as core techniques to reduce affective lability and eliminate eating disorder behaviors. Skills are taught both in group and individual therapy sessions and are meant to provide concrete ways to address urges to restrict, binge eat, and/or engage in inappropriate compensatory behaviors. The diary card is introduced at the onset of treatment and is used throughout treatment to track skills use and eating disorder behaviors outside of sessions. Similar to CBT, diary cards are reviewed at the beginning of each individual DBT session. Behavior chain analyses are a collaboration between clinicians and patients and used in session to visually diagram the antecedents and consequences of eating disorder behaviors. The purpose of the behavior chain analysis is to increase the patient’s awareness of the affective and behavioral correlates of eating disorder behavioral urges and actions.

Preliminary evidence suggests treating BN with DBT holds promise. In one randomized-controlled trial, 31 women with BN were randomized to DBT for BN or waitlist control²¹. At end-of-treatment, 28.6% of women with BN who received DBT were abstinent from binge eating and purging at end-of-treatment compared to no women with BN in the waitlist group, and this difference was statistically significant. More recently, a randomized-controlled trial tested the efficacy of an adapted form of DBT for BN that integrates satiety awareness training relative to a waitlist comparison condition in 31 women with BN²⁵. At end-of-treatment, 26.9% of women who received DBT were abstinent relative to the waitlist control group, a statistically significant difference.

Integrative Cognitive-Affective Therapy

Integrative Cognitive-Affective Therapy for BN (ICAT-BN) is a newer psychotherapy that emphasizes emotion regulation and coping, intrapersonal factors (self-discrepancy, nutrition), and interpersonal relationships²⁶. ICAT-BN was developed from the ICAT model of BN, which hypothesizes that self-discrepancy (mismatch between the actual and ideal self) leads to negative affect²⁷. Negative affect leads to self-directed coping strategies, such as self-criticism, and subsequent bulimic behaviors, which reinforce negative affect and onset an inexorable cycle of negative affect, self-directed coping, and bulimic behavior.

ICAT-BN is delivered in 21 sessions over four phases. In phase one, motivational interviewing is used to address ambivalence and psychoeducation around the role of emotions in bulimic symptoms is provided. Phase two centers on introduction and implementation of coping strategies and meal planning. In phase three, treatment is personalized to address factors that may maintain the individual’s bulimic symptoms according to the ICAT-BN model; personalized targets include self-directed coping (e.g., self-neglect, self-criticism), interpersonal problems (e.g., withdrawal, submissiveness), and/or self-discrepancy. Phase four focuses on planning and relapse prevention. Although similar to CBT, ICAT-BN is distinct with respect to its use of motivational interviewing at the onset of treatment, use of cognitive interventions that target self-discrepancies, and lack of use of cognitive restructuring.

Evidence for ICAT-BN is preliminary and is comprised of one randomized-controlled trial. Wonderlich et al. ²⁸ randomized 81 adults with BN to ICAT-BN or CBT-E. ICAT-BN and CBT-E did not significantly differ in abstinence rates at end-of-treatment (ICAT-BN 37.5% vs. CBT-E 22.5%) or four-month follow-up (ICAT-BN 32.5% vs. CBT-E 22.5%).

Children and Adolescents

Despite the fact that BN typically onsets in late adolescence, only four randomized-controlled trials have evaluated the efficacy of psychotherapies for adolescent BN. Below, we review the limited evidence base for psychotherapies for adolescent BN.

Family-Based Treatment

Family-based treatment for adolescent BN (FBT-BN) is an outpatient behavioral approach that centers on parental empowerment, normalization of adolescent eating patterns, and a return to normal adolescent development²⁹. The core tenants of FBT-BN include agnosticism with respect to the cause of BN, the philosophy that parents hold the knowledge and resources necessary to facilitate their child’s recovery from BN, and externalization of the illness from the adolescent.

FBT-BN consists of three phases delivered in 20 sessions over about six months. In the first phase of FBT-BN, parents are tasked with disrupting their adolescent’s eating disorder behaviors by providing regular meals and snacks and monitoring their child after meals and snacks to prevent inappropriate compensatory behaviors. With the resolution of eating disorder behaviors, in the second phase, developmentally appropriate autonomy over meals and snacks is gradually returned to the adolescent. Phase three commences once the adolescent demonstrates developmentally appropriate autonomy in feeding themselves and focuses on addressing typical adolescent development issues and helping the adolescent to build an identity outside of BN. Throughout FBT-BN, the adolescent is weighed at the beginning of each session. It is important to note that FBT-BN is contraindicated when FBT-BN is unacceptable (parents do not accept the FBT model and/or desire an individual approach), parents are unavailable to participate in treatment, or there is a history of abuse or neglect within the family.

Current clinical guidelines recommend FBT-BN for adolescent BN^7,30 and three randomized-controlled trials have evaluated the efficacy of FBT-BN to date. In one trial, 80 adolescents with BN were randomized to FBT-BN or individual supportive psychotherapy (SPT), a non-specific and non-directive approach ³¹. At end-of-treatment and 12-month follow-up, adolescents who received FBT-BN had statistically significantly greater rates of abstinence from eating disorder behaviors than those who received supportive psychotherapy (FBT-BN 39% vs. SPT 18% at end-of-treatment, FBT-BN 29% vs. SPT 10% at 12-month follow-up). In a second trial, 85 adolescents with BN were randomized to a Maudsley model of family therapy or guided self-help CBT-BN. A significantly greater proportion of adolescents who received guided self-help CBT-BN were abstinent from eating disorder behaviors than adolescents who received family therapy at end-of-treatment; however, at six-month follow-up, there were no statistical differences between groups with respect to abstinence from eating disorder behaviors. In a third trial, 130 adolescents with BN were randomized to FBT-BN or CBT adapted for adolescents (CBT-A, reviewed in detail below), a modified version of CBT-BN that includes collateral sessions with parents and integration of developmental elements³². At end-of-treatment and 6-month follow-up, adolescents who received FBT-BN had statistically significantly greater rates of abstinence from eating disorder behaviors than adolescents who received CBT-A (FBT-BN 39.4% vs. CBT-A 19.7% at end-of-treatment, FBT-BN 44% vs. CBT-A 25.4% at 6-month follow-up). A 12-month follow-up analysis showed that abstinence rates did not statistically differ between groups. Together, results provide preliminary evidence that FBT-BN is an efficacious treatment for BN; however, additional study is needed to understand the long-term efficacy of FBT-BN relative to other treatments.

Cognitive-Behavioral Therapy Adapted for Adolescents

CBT adapted for adolescents (CBT-A) incorporates parent collateral sessions into CBT-BN and addresses adolescent developmental considerations³³. CBT-A employs the same staged approach as CBT-BN to introduce behavioral and cognitive techniques to address bulimic symptoms in adolescent BN. In CBT-A, parent collateral sessions are scheduled throughout treatment and parents may be actively involved in the treatment at the discretion of the adolescent. In the initial behavioral phase of CBT-A, parents are oriented to the BN diagnosis, provided psychoeducation around regular eating and self-monitoring, and encouraged to structure the home to support recovery. If the adolescent desires, parents may assist with meal and snack planning, as well as monitoring to prevent compensatory behaviors following eating. Parents are encouraged to reinforce adolescent behaviors that are incompatible with bulimic behaviors. In the second cognitively-focused phase of CBT-A, parents help to identify socioemotional triggers for bulimic symptoms and may assist the adolescent in problem-solving and cognitive restructuring. In the maintenance and relapse prevention phase of CBT-A, parents consider developmental transitions that may increase risk of relapse, such as leaving for college, and identify strategies to support their adolescent and prevent a relapse.

There has been one randomized-controlled trial of CBT-A. This previously described trial randomized adolescents with BN to CBT-A or FBT-BN, and found that FBT-BN was statistically superior in promoting abstinence of binge eating and purging behavior at end-of-treatment and six-month follow-up ³². However, the abstinence rates for FBT-BN and CBT-A did not statistically differ at one-year follow up (FBT-BN 49% vs. CBT-A 33%). Two other trials have examined the efficacy of CBT-BN in adolescents to date. One previously mentioned trial randomized adolescents with BN to guided self-help CBT-BN or family therapy, and found that guided self-help CBT was statistically superior to family therapy in promoting abstinence of eating disorder behaviors at end-of-treatment, but not at six-month follow-up ³⁴. The second is a recent trial that randomized 81 adolescent girls with BN to CBT-BN or psychodynamic therapy for BN ³⁵. There were no significant differences in remission (defined as no longer meeting criteria for an eating disorder) between CBT-BN and psychodynamic therapy at end-of-treatment (CBT-BN 33.3% vs. psychodynamic 31%) and one-year follow-up (CBT-BN 38.5% vs. psychodynamic 31%). Outcomes from these trials suggest that CBT is a suitable treatment for adolescent BN, though more research is warranted. In addition, CBT could be considered when FBT-BN is unacceptable or contraindicated ⁷.

Pharmacotherapy

Psychotherapy is typically considered the treatment of choice for BN. However, pharmacotherapy may be considered as a standalone treatment for BN if psychotherapy is unavailable or ineffective ³⁶ and may depend on the type of psychotherapy¹². For instance, a randomized-controlled trial of 120 women with BN examined the efficacy of combined psychotherapy (CBT or supportive psychotherapy) and medication relative to medication alone¹² Results suggested that combined CBT and medication was superior to medication alone in promoting reductions in BN symptoms, while combined supportive psychotherapy and medication did not outperform medication alone. Thus, medication may be considered as a standalone treatment if CBT-BN is unavailable.

To date, no psychotropic medications have been developed to specifically treat BN. Rather, medications developed for other conditions, namely antidepressants and antiepileptics, have been examined in adults with BN with moderate efficacy relative to placebo ³⁷ Strikingly, just one open trial of pharmacotherapy for adolescent BN has been conducted ³⁸. Overall, there are relatively few ongoing pharmacotherapy trials in BN and few new developments, perhaps due to the established efficacy of current medications (described below) ³⁷.

Antidepressant Medications

Soon after BN was first clearly described in 1979 ³⁹, it was recognized that many patients with BN experienced significant depression and anxiety. This led to initial trials in the early 1980s to examine the potential utility of antidepressant medication ^40,41. Subsequently, multiple controlled trials of a range of antidepressant medications documented their efficacy compared to placebo. Based on large trials supported by Eli Lilly and Company, the selective serotonin reuptake inhibitor (SSRI) fluoxetine was approved by the FDA for the treatment of BN in adults, and, given its efficacy and a generally low incidence of side effects, is the pharmacological treatment of choice ⁴² Moreover, results suggested that 60 mg/day of fluoxetine facilitated reductions in binge eating and purging even in the absence of comorbid depression ⁴². Based on this study, fluoxetine is typically prescribed at 60 mg/day for BN, in contrast to the 20 mg/day dose typically prescribed for depression. Additionally, fluoxetine has demonstrated promise over placebo in adults with BN who had poor response to psychotherapy ³⁶. This finding suggests that fluoxetine may be useful when psychotherapy is ineffective.

With respect to medication in adolescents with BN, a single open-label trial examined fluoxetine 60mg/day in 10 adolescent girls with BN over an 8-week period ³⁸. Results were encouraging and suggested significant reductions in binge eating and purging frequencies, and that the medication was accepted and tolerated with few side effects. Given the elevated risk of suicide in adolescent BN ⁴³ and concerns about SSRIs increasing suicidality in youths ⁴⁴, it is important to carefully monitor adolescents with BN prescribed SSRIs.

Antiepileptic Medications

Topiramate is a medication used to treat epilepsy with known effects on appetite regulation and weight that has been evaluated for the treatment of adult BN in two randomized-controlled trials. Both trials showed that topiramate facilitated meaningful reductions in binge eating and purging frequencies and attitudinal measures ³⁷. However, one randomized-controlled trial found that women with BN randomized to topiramate lost significantly more weight than those randomized to placebo ⁴⁵. In addition, topiramate is associated with troublesome side effects such as cognitive slowing, paresthesias, and kidney stones. Thus, topiramate is not considered a first-line treatment for BN.

Synthesis and Recommendations

At present, the first-choice treatment for BN is outpatient psychotherapy. For adults with the disorder, clinical guidelines informed by empirical research recommend therapist-led CBT. In addition, guided self-help CBT may be useful for patients without access to specialty eating disorder clinicians or who have financial and/or insurance barriers. IPT is a reasonable second-line evidenced-based psychological treatment for adults with BN and may be particularly useful in those with marked interpersonal difficulties. DBT and ICAT-BN show initial promise for the treatment of adult BN, though more research is needed. The pharmacotherapy of choice for BN is fluoxetine prescribed at 60 mg/day. Pharmacotherapy should generally be considered adjunctive to psychotherapy, but standalone pharmacotherapy may be indicated when psychotherapy is unavailable or ineffective and may depend on the type of psychotherapy available.

In contrast to the dozens of psychotherapy and medication trials for adult BN, only four psychotherapy trials and one medication trial for adolescents with BN have been published to date. FBT-BN is recommended for adolescents and individual CBT is an acceptable alternative. Fluoxetine 60 mg/day appears to have benefit and is acceptable to adolescents with BN.

Looking forward, there are several important issues to be considered to advance the treatment of BN. One issue is that despite decades of research, approximately 60% of individuals with BN who receive the best-available treatments do not achieve symptom abstinence ⁴⁶. Another key issue relates to the access, cost, and dissemination of specialty BN treatments. One way that this issue has been addressed is through guided self-help therapies, like CBT ¹⁰. It might also be useful to identify to identify the specific components of current and novel treatments that are beneficial, inert, or harmful is through the multiphasic optimization strategy (MOST) ⁴⁷. MOST offers a way to isolate and efficiently test treatment components, and may ultimately help to streamline treatments by removing components that offer little benefit. Streamlining BN treatments may be of use in increasing their effectiveness, reducing their cost, and improving dissemination. Finally, further study of both pharmacologic and psychological treatments for adolescent BN is warranted given the scant evidence base.