Progress in Developing Pharmacologic Agents to Treat Bulimia Nervosa

Stimulant medications in the management of bulimia nervosa and anorexia nervosa in patients with and without comorbid attention deficit hyperactivity disorder: A systematic review

OBJECTIVE

People with attentional problems are at increased risk of eating disorders. This paper aimed to systematically review and synthesize the existing evidence on stimulant medication in the management of patients with bulimia nervosa (BN) or anorexia nervosa (AN) with or without comorbid attention deficit hyperactivity disorder (ADHD).

METHOD

A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. A protocol for the review was registered with Open Science Framework (OSF) Registry and critical appraisal of the literature was conducted using Joanna Briggs Institute (JBI) Critical Appraisal Tools.

RESULTS

Thirteen articles met inclusion criteria including two quasi-experimental studies, one randomized controlled trial, four case series, and six case reports. 26 cases were included from studies and 32 from case series/reports. Only two cases from a single case report had a diagnosis of AN, while the remainder had BN. Stimulants included methylamphetamine, lisdexamfetamine, methylphenidate, dextroamphetamine sulphate and mixed amphetamine salt. In nearly all cases of BN there were reported reductions in eating disorder symptoms. The rates of adverse effects were high and included weight loss, decreased appetite, tachycardia, dry mouth, fatigue, insomnia, restlessness, nausea, bruxism, headache, palpitations, blood pressure changes, irritability, anxiety, depressed mood, and diaphoresis.

CONCLUSION

There is currently insufficient evidence to support the use of stimulant medications to treat symptoms of BN or AN. The authors recommend considering screening patients with BN for ADHD.

Treatment of Eating Disorders: Current Status, Challenges, and Future Directions

Specific psychological treatments have demonstrated efficacy and represent the first-line approaches recommended for anorexia nervosa, bulimia nervosa, and binge-eating disorder. Unfortunately, many patients, particularly those with anorexia nervosa, do not derive sufficient benefit from existing treatments, and better or alternative treatments for eating disorders are needed. Less progress has been made in developing pharmacologic options for eating disorders. No medications approved for anorexia nervosa exist, and only one each exists for bulimia nervosa and for binge-eating disorder; available data indicate that most patients fail to benefit from available medications. Longer and combined treatments have generally not enhanced outcomes. This review presents emerging findings from more complex and clinically relevant adaptive treatment designs, as they offer some clinical guidance and may serve as models for future enhanced treatment research.

World Federation of Societies of Biological Psychiatry (WFSBP) guidelines update 2023 on the pharmacological treatment of eating disorders

OBJECTIVES

This 2023 update of the WFSBP guidelines for the pharmacological treatment of eating disorders (EDs) reflects the latest diagnostic and psychopharmacological progress and the improved WFSBP recommendations for the assessment of the level of evidence (LoE) and the grade of recommendation (GoR).

METHODS

The WFSBP Task Force EDs reviewed the relevant literature and provided a timely grading of the LoE and the GoR.

RESULTS

In anorexia nervosa (AN), only a limited recommendation (LoE: A; GoR: 2) for olanzapine can be given, because the available evidence is restricted to weight gain, and its effect on psychopathology is less clear. In bulimia nervosa (BN), the current literature prompts a recommendation for fluoxetine (LoE: A; GoR: 1) or topiramate (LoE: A; GoR: 1). In binge-eating disorder (BED), lisdexamfetamine (LDX; LoE: A; GoR: 1) or topiramate (LoE: A; GoR: 1) can be recommended. There is only sparse evidence for the drug treatment of avoidant restrictive food intake disorder (ARFID), pica, and rumination disorder (RD).

CONCLUSION

In BN, fluoxetine, and topiramate, and in BED, LDX and topiramate can be recommended. Despite the published evidence, olanzapine and topiramate have not received marketing authorisation for use in EDs from any medicine regulatory agency.

Accessibility of Psychological Treatments for Bulimia Nervosa: A Review of Efficacy and Engagement in Online Self-Help Treatments

Bulimia nervosa is an eating disorder characterised by marked impairment to one's physical health and social functioning, as well as high rates of chronicity and comorbidity. This literature review aims to summarise existing academic research related to the symptom profile of BN, the costs and burden imposed by the illness, barriers to the receipt of care, and the evidence base for available psychological treatments. As a consequence of well-documented difficulties in accessing evidence-based treatments for eating disorders, efforts have been made towards developing innovative, diverse channels to deliver treatment, with several of these attempting to harness the potential of digital platforms. In response to the increasing number of trials investigating the utility of online treatments, this paper provides a critical review of previous attempts to examine digital interventions in the treatment of eating disorders. The results of a focused literature review are presented, including a detailed synthesis of a knowledgeable selection of high-quality articles with the aim of providing an update on the current state of research in the field. The results of the review highlight the potential for online self-help treatments to produce moderately sized reductions in core behavioural and cognitive symptoms of eating disorders. However, concern is raised regarding the methodological limitations of previous research in the field, as well as the high rates of dropout and poor adherence reported across most studies. The review suggests directions for future research, including the need to replicate previous findings using rigorous study design and methodology, as well as further investigation regarding the utility of clinician support and interactive digital features as potential mechanisms for offsetting low rates of engagement with online treatments.

Psychiatric medication use by Canadian adults prior to entering an outpatient eating disorders program: Types and combinations of medications, predictors of being on a medication, and clinical considerations

This study examined the proportion of Canadian adults who were on psychiatric medication prior to entering specialized outpatient care for an eating disorder, the types and combinations of medications taken, and predictors of being on a medication. A retrospective chart review of 223 adults with an eating disorder was conducted. A large proportion of the adults (61%) had been prescribed a psychiatric medication prior to entering specialized outpatient care. Of these adults, 74.6% were prescribed one medication and 24.3% were on a combination of two or more. Antidepressant and anti-anxiety medications were the most commonly prescribed (78%), while stimulant medications (2.1%), benzodiazepines (13.7%), and antipsychotics (10.7%) were also reported. Being at a higher weight status was a significant predictor of being on a psychiatric medication at intake assessment. Adults with comorbid depression were 2.68 times more likely to be on a psychiatric medication. Although the number of Canadian adults on psychiatric medication may well exceed the documented efficacy of these medications for eating disorders, psychopharmacological intervention could have been aimed at targeting comorbid conditions. Clinicians specializing in pharmacology and eating disorders may have an important role to provide psychoeducation to all providers.

A matter of time: A systematic scoping review on a potential role of the circadian system in binge eating behavior

Background

Emerging research suggests that food intake timing, eating behavior and food preference are associated with aspects of the circadian system function but the role that the circadian system may play in binge eating (BE) behavior in humans remains unclear.

Objective

To systematically evaluate the evidence for circadian system involvement in BE behavior.

Methods

Systematic searches of PubMed, EMBASE, and Scopus were performed for reports published from inception until May 2020 (PROSPERO Registration CRD42020186325). Searches were conducted by combining Medical Subject Headings related to the circadian system, BE behavior, and/or interventions. Observational and interventional studies in humans with BE behavior published in peer-review journals in the English language were included. Studies were assessed using quality and risk of bias tools (AXIS, ROB 2.0, or ROBINS).

Results

The search produced 660 articles, 51 of which were included in this review. Of these articles, 46 were observational studies and 5 were interventional trials. Evidence from these studies suggests that individuals with BE behavior tend to have more food intake, more binge cravings, and more BE episodes later in the day. Hormonal and day/night locomotor activity rhythm disturbances may be associated with BE behavior. Furthermore, late diurnal preference ("eveningness") was associated with BE behavior and chronobiological interventions that shift the circadian clock earlier (e.g., morning bright light therapy) were found to possibly decrease BE behavior. Substantive clinical overlap exists between BE and night eating behavior. However, there is a significant knowledge gap regarding their potential relationship with the circadian system. Limitations include the lack of studies that use best-established techniques to assess the chronobiology of BE behavior, heterogeneity of participants, diagnostic criteria, and study design, which preclude a meta-analytic approach.

Conclusion

Current evidence, although limited, suggests that the circadian system may play a role in the etiology of BE behavior. Further mechanistic studies are needed to fully characterize a potential role of the circadian system in BE behavior. A chronobiological approach to studying BE behavior may lead to identification of its neurobiological components and development of novel therapeutic interventions.

Systematic review registration

[https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020186325], identifier [CRD42020186325].

Brain serotonin deficiency and fluoxetine lead to sex-specific effects on binge-like food consumption in mice

RATIONALE

Although pharmacotherapies are often effective in reducing binge eating in conditions such as bulimia nervosa and binge eating disorder, subsets of patients do not benefit sufficiently from existing treatments, and the reasons for treatment failure remain unclear.

OBJECTIVES

This study aimed to evaluate whether genetic reductions in brain serotonin influence binge eating and/or the ability of fluoxetine, a selective serotonin reuptake inhibitor, to reduce binge eating in mice.

METHODS

This study used a validated model of binge-like consumption of high-fat diet to compare binge-like food intake in control and fluoxetine-treated wild-type and serotonin-deficient mice from the tryptophan hydroxylase 2 (R439H) knock-in line. In addition, real-time PCR was used to evaluate potential genotype and sex differences in the effects of fluoxetine on gene expression in the raphe nucleus.

RESULTS

The results reveal that brain serotonin deficiency is sufficient to increase binge eating in males, but not females. However, while chronic fluoxetine reduced binge eating in both genotypes of males and in wild-type females, it failed to reduce binge eating in serotonin-deficient females. Transcriptional responses to chronic fluoxetine were also characterized by sex and genotype differences.

CONCLUSIONS

Overall, this study revealed significant sex differences in the effects of fluoxetine and brain serotonin deficiency on binge-like food intake and suggests that low brain serotonin could impact eating disorders both by promoting binge eating and by limiting the efficacy of fluoxetine to reduce binge eating.

Physiological Role of Orexinergic System for Health

Orexins, or hypocretins, are excitatory neuropeptides involved in the regulation of feeding behavior and the sleep and wakefulness states. Since their discovery, several lines of evidence have highlighted that orexin neurons regulate a great range of physiological functions, giving it the definition of a multitasking system. In the present review, we firstly describe the mechanisms underlining the orexin system and their interactions with the central nervous system (CNS). Then, the system's involvement in goal-directed behaviors, sleep/wakefulness state regulation, feeding behavior and energy homeostasis, reward system, and aging and neurodegenerative diseases are described. Advanced evidence suggests that the orexin system is crucial for regulating many physiological functions and could represent a promising target for therapeutical approaches to obesity, drug addiction, and emotional stress.

Hypocretins (orexins): The ultimate translational neuropeptides

The hypocretins (Hcrts), also known as orexins, are two neuropeptides produced exclusively in the lateral hypothalamus. They act on two specific receptors that are widely distributed across the brain and involved in a myriad of neurophysiological functions that include sleep, arousal, feeding, reward, fear, anxiety and cognition. Hcrt cell loss in humans leads to narcolepsy with cataplexy (narcolepsy type 1), a disorder characterized by intrusions of sleep into wakefulness, demonstrating that the Hcrt system is nonredundant and essential for sleep/wake stability. The causal link between Hcrts and arousal/wakefulness stabilisation has led to the development of a new class of drugs, Hcrt receptor antagonists to treat insomnia, based on the assumption that blocking orexin-induced arousal will facilitate sleep. This has been clinically validated: currently, two Hcrt receptor antagonists are approved to treat insomnia (suvorexant and lemborexant), with a New Drug Application recently submitted to the US Food and Drug Administration for a third drug (daridorexant). Other therapeutic applications under investigation include reduction of cravings in substance-use disorders and prevention of neurodegenerative disorders such as Alzheimer's disease, given the apparent bidirectional relationship between poor sleep and worsening of the disease. Circuit neuroscience findings suggest that the Hcrt system is a hub that integrates diverse inputs modulating arousal (e.g., circadian rhythms, metabolic status, positive and negative emotions) and conveys this information to multiple output regions. This neuronal architecture explains the wealth of physiological functions associated with Hcrts and highlights the potential of the Hcrt system as a therapeutic target for a number of disorders. We discuss present and future possible applications of drugs targeting the Hcrt system for the treatment of circuit-related neuropsychiatric and neurodegenerative conditions.

Eating disorders and subsequent risk of substance use disorders involving illicit drugs: a Danish nationwide register-based cohort study

PURPOSE

No study has investigated the ongoing risk of substance use disorders involving illicit drugs (ISUD) after first eating disorder (ED) and whether the pattern of risk differs according to types of ED and ISUD. Therefore, we aimed to longitudinally assess the risk of a subsequent diagnosis of any ISUD (pooled category) and specific ISUD after a first-time diagnosis of anorexia nervosa (AN), bulimia nervosa (BN), or unspecified ED (USED).

METHODS

A retrospective cohort study using data from Danish nationwide registers identified 20,759 ED patients and 83,038 matched controls (1:4 ratio). Risk of any ISUD diagnosis after first ED diagnosis was estimated by generating hazard ratios (HR). Logistic regression was applied to assess associations between each ED and specific ISUD.

RESULTS

Patients with AN, BN, and USED (without a prior ISUD diagnosis) exhibited an increased relative risk of a subsequent diagnosis of any ISUD compared with respective controls, and the elevated risk persisted over 10 years (AN, adjusted HRs ranging from 1.60 [99% CI 1.15-2.24] to 5.16 [3.14-8.47]; BN, 2.35 [1.46-3.79] to 14.24 [6.88-29.47]; USED, 2.86 [1.35-3.79] to 8.56 [3.31-29.47]). The highest estimates were observed during the first year of follow-up. Each ED type was associated with an increased likelihood of all types of ISUD. AN and USED were most strongly associated with sedatives/hypnotics, BN with other illegal substances (e.g., ecstasy and hallucinogens).

CONCLUSIONS

ED patients have a considerable risk for subsequent ISUD. Prevention efforts and treatment targeting ISUD are likely required to improve ED treatment prognosis.

Ketamine as a Novel Psychopharmacotherapy for Eating Disorders: Evidence and Future Directions

Eating disorders (EDs) are serious, life-threatening psychiatric conditions associated with physical and psychosocial impairment, as well as high morbidity and mortality. Given the chronic refractory nature of EDs and the paucity of evidence-based treatments, there is a pressing need to identify novel approaches for this population. The noncompetitive N-methyl-D-aspartate receptor (NMDAr) antagonist, ketamine, has recently been approved for treatment-resistant depression, exerting rapid and robust antidepressant effects. It is now being investigated for several new indications, including obsessive–compulsive, post-traumatic, and substance use disorder, and shows transdiagnostic potential for EDs, particularly among clinical nonresponders. Hence, the aim of this review is to examine contemporary findings on the treatment of EDs with ketamine, whether used as a primary, adjunctive, or combination psychopharmacotherapy. Avenues for future research are also discussed. Overall, results are encouraging and point to therapeutic value; however, are limited to case series and reports on anorexia nervosa. Further empirical research is thus needed to explore ketamine efficacy across ED subgroups, establish safety profiles and optimize dosing, and develop theory-driven, targeted treatment strategies at the individual patient level.

A feasibility study evaluating lisdexamfetamine dimesylate for the treatment of adults with bulimia nervosa

OBJECTIVE

This study examined the feasibility, safety, and potential efficacy of lisdexamfetamine (LDX) as a treatment for adults with bulimia nervosa (BN).

METHOD

An open-label 8-week feasibility study was conducted in participants with BN. Enrollment rate, dropout rate, safety outcomes, and eating disorder symptom change were examined.

RESULTS

Eighteen of 23 participants completed the study per protocol. There was no participant-initiated dropout due to adverse drug reactions and no severe and unexpected adverse drug reactions. An average increase in heart rate of 12.1 beats/min was observed. There was a mean weight reduction of 2.1 kg and one participant was withdrawn for clinically significant weight loss. In the intent-to-treat sample, there were reductions in objective binge episodes and compensatory behaviors from Baseline to Post/End-of-Treatment (mean difference = -29.83, 95% confidence interval: -43.38 to -16.27; and mean difference = -33.78, 95% confidence interval: -48.74 to -18.82, respectively).

DISCUSSION

Results of this study indicate that a randomized controlled trial would be feasible with close monitoring of certain safety parameters (especially over a longer time period as long-term safety is unknown). However, the results should not be used as evidence for clinicians to prescribe LDX to individuals with BN before its efficacy and safety are properly tested.

TRIAL REGISTRATION NUMBER

NCT03397446.

Dietetic intervention for adult outpatients with an eating disorder: a systematic review and assessment of evidence quality

CONTEXT

Eating disorders (EDs) are complex mental illnesses that require medical, psychological, and dietetic intervention to assist patients achieve recovery.

OBJECTIVE

Available evidence was reviewed regarding dietetic intervention for adult outpatients with an ED and the quality of this evidence was assessed.

DATA SOURCES

Systematic literature searches were conducted using 5 databases (MEDLINE, PreMEDLINE, EMBASE, CINAHL, PsycINFO) for studies comparing adults with an ED receiving a dietetic intervention with those receiving a psychological intervention alone, those receiving a combined dietetic and psychological intervention, or a control group.

DATA EXTRACTION

Literature searches returned 3078 results, with 10 articles reporting on 9 randomized controlled trials meeting the inclusion criteria. The quality of evidence was assessed using the Cochrane Risk-of-Bias tool and Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework.

DATA ANALYSIS

GRADE assessments for studies involving individuals with anorexia nervosa indicated very low quality of evidence for outcomes including weight, ED psychopathology and ED behaviors , and no studies measured nutritional changes. For studies conducted with participants with bulimia nervosa or binge eating disorder, only 1 study included a group receiving combined evidence-based psychological and dietetic intervention. A combined intervention produced moderate-quality evidence for lower attrition, greater abstinence from ED behaviors, and more meals eaten per week in comparison with a stand-alone psychological or dietetic intervention.

CONCLUSIONS

There is currently limited evidence to sufficiently assess the impact of incorporating dietetic interventions into outpatient treatment for adults with an ED; however, available evidence supports clinical practice guidelines that dietetic intervention should not be delivered as a stand-alone treatment. Additional methodologically sound studies in larger samples are required to fully inform dietetic treatment in EDs and incorporation of such interventions as part of a multidisciplinary treatment approach.

State of the Art: The Therapeutic Approaches to Bulimia Nervosa

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 weight. BN is a serious disorder with medical sequelae and marked psychosocial impairment. To reduce and eliminate symptoms of BN, psychological and pharmacologic treatments for BN have been developed. 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

Currently, 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 are also promising. For BN in adolescents, 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/d is the medication of choice for adults with BN. Little is known with respect to pharmacologic treatment of BN in adolescents, although fluoxetine 60 mg/d holds promise.

IMPLICATIONS

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

Pharmacological treatment of eating disorders, comorbid mental health problems, malnutrition and physical health consequences

The pharmacological treatment of patients with an eating disorder (ED) often includes medications to treat their ED, comorbid mental health problems, malnutrition and the physical health problems resulting from it. The currently approved pharmacological treatment options for EDs are limited to fluoxetine for bulimia nervosa (BN) and - in some countries - lisdexamfetamine for binge eating disorder (BED). Thus, there are no approved pharmacological options for anorexia nervosa (AN), even though study results for olanzapine and dronabinol are promising. Topiramate might be an additional future option for the treatment of BN and BED. Selective serotonin reuptake inhibitors (SSRI), mirtazapine and bupropion could be considered for the treatment of comorbid unipolar depression. However, AN and BN are contraindications for bupropion. For ED patients with a manic episode, we recommend olanzapine in AN and risperidone in BN and BED; whereas for bipolar depression, olanzapine (plus fluoxetine) seems appropriate in AN and lamotrigine in BN and BED. Acute anxiety or suicidality may warrant benzodiazepine treatment with lorazepam. Proton-pump inhibitors, gastroprokinetic drugs, laxatives and hormones can alleviate certain physical health problems caused by EDs. Therapeutic drug monitoring, pharmacogenomic testing, a more restrictive use of "pro re nata" (PRN) medication, an interdisciplinary treatment approach, shared decision making (SDM) and the formulation of common treatment goals by the patients, their family or carers and clinicians could improve treatment success and safety. Novel genetic, immunological, microbiome and brain imaging research as well as new pharmacological developments like the use of psychedelics, stimulants, novel monoaminergic drugs, hormone analogues and drugs which enhance the effects of psychotherapy may extend our therapeutic options in the near future.

Fish as models for understanding the vertebrate endocrine regulation of feeding and weight

The frequencies of eating disorders and obesity have increased worldwide in recent years. Their pathophysiologies are still unclear, but recent evidence suggests that they might be related to changes in endocrine and neural factors that regulate feeding and energy homeostasis. In order to develop efficient therapeutic drugs, a more thorough knowledge of the neuronal circuits and mechanisms involved is needed. Although to date, rodents have mostly been used models in the area of neuroscience and neuroendocrinology, an increasing number of studies use non-mammalian vertebrates, in particular fish, as model systems. Fish present several advantages over mammalian models and they share genetic and physiological homology to mammals with close similarities in the mechanisms involved in the neural and endocrine regulation of appetite. This review briefly describes the regulation of feeding in two model species, goldfish and zebrafish, how this regulation compares to that in mammals, and how these fish could be used for studies on endocrine regulation of eating and weight and its dysregulations.