Emerging drugs for eating disorder treatment

Pharmacotherapy compared to placebo for people with Bulimia Nervosa: A systematic review and meta-analysis

Bulimia Nervosa is a disorder with high rates of psychiatric and medical comorbidity and substantial societal costs. Cognitive Behavioural Therapy is considered the preferred treatment, but access can be problematic. Pharmacotherapy is more accessible but remains significantly underutilised. We aimed to assess the efficacy, tolerability, and safety of all available forms of pharmacotherapy for the treatment of bulimia nervosa. We conducted a comprehensive search of PubMed, EMBASE, CENTRAL, ClinicalTrials.gov, and reference lists of relevant articles up until April 2023. The primary outcomes were remission and binge frequency. 52 randomised controlled trials (RCTs) involving 3313 participants were included in the meta-analysis. Overall, no significant difference was observed between drugs and placebo in terms of remission; however, the available data were limited. Notably, drugs, particularly antidepressants, demonstrated a significant reduction in the frequency of binge episodes compared to placebo. Antidepressants were also found to be more effective than placebo in terms of treatment response and other clinically meaningful outcomes. An important limitation is that few RCTs were available for individual drugs. Our findings provide evidence supporting the increased utilisation of pharmacotherapy in clinical practice and underscore the need for further research involving larger populations and a broader range of outcomes.

Use of experimental medicine approaches for the development of novel psychiatric treatments based on orexin receptor modulation

Despite progress in understanding the pathological mechanisms underlying psychiatric disorders, translation from animal models into clinical use remains a significant bottleneck. Preclinical studies have implicated the orexin neuropeptide system as a potential target for psychiatric disorders through its role in regulating emotional, cognitive, and behavioral processes. Clinical studies are investigating orexin modulation in addiction and mood disorders. Here we review performance-outcome measures (POMs) arising from experimental medicine research methods which may show promise as markers of efficacy of orexin receptor modulators in humans. POMs provide objective measures of brain function, complementing patient-reported or clinician-observed symptom evaluation, and aid the translation from preclinical to clinical research. Significant challenges include the development, validation, and operationalization of these measures. We suggest that collaborative networks comprising clinical practitioners, academics, individuals working in the pharmaceutical industry, drug regulators, patients, patient advocacy groups, and other relevant stakeholders may provide infrastructure to facilitate validation of experimental medicine approaches in translational research and in the implementation of these approaches in real-world clinical practice.

Comment on Keeler et al. Ketamine as a Treatment for Anorexia Nervosa: A Narrative Review. Nutrients 2021, 13, 4158

Anorexia Nervosa (AN) represents a difficult therapeutic challenge, with up to 4% prevalence among females and increasing incidence among youth [...]

Histamine H3 Heteroreceptors Suppress Glutamatergic and GABAergic Synaptic Transmission in the Rat Insular Cortex

Histamine H₃ receptors are autoreceptors that regulate histamine release from histaminergic neuronal terminals. The cerebral cortex, including the insular cortex (IC), expresses abundant H₃ receptors; however, the functions and mechanisms of H₃ receptors remain unknown. The aim of this study was to elucidate the functional roles of H₃ in synaptic transmission in layer V of the rat IC. Unitary excitatory and inhibitory postsynaptic currents (uEPSCs and uIPSCs) were obtained through paired whole-cell patch-clamp recording in cerebrocortical slice preparations. The H₃ receptor agonist, R-α-methylhistamine (RAMH), reduced the uEPSC amplitude obtained from pyramidal cell to pyramidal cell or GABAergic interneuron connections. Similarly, RAMH reduced the uIPSC amplitude in GABAergic interneuron to pyramidal cell connections. RAMH-induced decreases in both the uEPSC and uIPSC amplitudes were accompanied by increases in the failure rate and paired-pulse ratio. JNJ 5207852 dihydrochloride or thioperamide, H₃ receptor antagonists, inhibited RAMH-induced suppression of uEPSCs and uIPSCs. Unexpectedly, thioperamide alone increased the uIPSC amplitude, suggesting that thioperamide was likely to act as an inverse agonist. Miniature EPSC or IPSC recordings support the hypothesis that the activation of H₃ receptors suppresses the release of glutamate and GABA from presynaptic terminals. The colocalization of H₃ receptors and glutamate decarboxylase or vesicular glutamate transport protein 1 in presynaptic axon terminals was confirmed through double pre-embedding microscopy, using a combination of pre-embedding immunogold and immunoperoxidase techniques. The suppressive regulation of H₃ heteroreceptors on synaptic transmission might mediate the regulation of sensory information processes, such as gustation and visceral sensation, in the IC.

Use of Psychopharmacologic Medications in Adolescents With Restrictive Eating Disorders: Analysis of Data From the National Eating Disorder Quality Improvement Collaborative

PURPOSE

Psychopharmacologic medications are often prescribed to patients with restrictive eating disorders (EDs), and little is known about the frequency of use in adolescents. We examined the use of psychopharmacologic medications in adolescents referred for treatment of restrictive ED, potential factors associated with their use, and reported psychiatric comorbidities.

METHODS

Retrospective data from the initial and 1-year visits were collected for patients referred for evaluation of restrictive ED at 12 adolescent-based ED programs during 2010 (Group 1), including diagnosis, demographic information, body mass index, prior treatment modalities, and psychopharmacologic medications. Additional data regarding patients' comorbid psychiatric conditions and classes of psychopharmacologic medications were obtained from six sites (Group 2).

RESULTS

Overall, 635 patients met inclusion criteria and 359 had 1-year follow-up (Group 1). At intake, 20.4% of Group 1 was taking psychopharmacologic medication and 58.7% at 1 year (p ≤ .0001). White, non-Hispanic race (p = .020), and prior higher level of care (p < .0001) were positively associated with medication use at 1 year. Among Group 2 (n = 256), serotonin reuptake inhibitors/serotonin-norepinephrine reuptake inhibitors use was most common, and 62.6% had a reported psychiatric comorbidity. Presence of any psychiatric comorbidity was highly associated with medication use; odds ratio, 10.0 (5.6, 18.0).

CONCLUSIONS

Adolescents with restrictive ED treated at referral centers have high rates of reported psychopharmacologic medication use and psychiatric comorbidity. As more than half of this referral population were reported to be taking medication, continued investigation is warranted to ensure the desired outcomes of the medications are being met.

Pharmacological management of binge eating disorder: current and emerging treatment options

Growing evidence suggests that pharmacotherapy may be beneficial for some patients with binge eating disorder (BED), an eating disorder characterized by repetitive episodes of uncontrollable consumption of abnormally large amounts of food without inappropriate weight loss behaviors. In this paper, we provide a brief overview of BED and review the rationales and data supporting the effectiveness of specific medications or medication classes in treating patients with BED. We conclude by summarizing these data, discussing the role of pharmacotherapy in the BED treatment armamentarium, and suggesting future areas for research.

SEP-225289 serotonin and dopamine transporter occupancy: a PET study

SEP-225289 is a novel compound that, based on in vitro potencies for transporter function, potentially inhibits reuptake at dopamine, norepinephrine, and serotonin transporters. An open-label PET study was conducted during the development of SEP-225289 to investigate its dopamine and serotonin transporter occupancy.

METHODS

Different single doses of SEP-225289 were administered to healthy volunteers in 3 cohorts: 8 mg (n = 7), 12 mg (n = 5), and 16 mg (n = 7). PET was performed before and approximately 24 h after oral administration of SEP-225289, to assess occupancy at trough levels. Dopamine and serotonin transporter occupancies were estimated from PET using (11)C-N-(3-iodoprop-2E-enyl)-2β-carbomethoxy-3β-(4-methylphenyl)nortropane ((11)C-PE2I) and (11)C-N,N-dimethyl-2-(2-amino-4-cyanophenylthio)benzylamine ((11)C-DASB), respectively. Plasma concentration of SEP-225289 was assessed before ligand injection, and subjects were monitored for adverse events.

RESULTS

Average dopamine and serotonin transporter occupancies increased with increasing doses of SEP-225289. Mean dopamine and serotonin transporter occupancies were 33% ± 11% and 2% ± 13%, respectively, for 8 mg; 44% ± 4% and 9% ± 10%, respectively, for 12 mg; and 49% ± 7% and 14% ± 15%, respectively, for 16 mg. On the basis of the relationship between occupancy and plasma concentration, dopamine transporter IC(50) (the plasma concentration of drug at 50% occupancy) was determined (4.5 ng/mL) and maximum dopamine transporter occupancy was extrapolated (85%); however, low serotonin transporter occupancy prevented similar serotonin transporter calculations. No serious adverse events were reported.

CONCLUSION

At the doses evaluated, occupancy of the dopamine transporter was significantly higher than that of the serotonin transporter, despite similar in vitro potencies, confirming that, in addition to in vitro assays, PET occupancy studies can be instrumental to the drug development process by informing early decisions about indication, dose, and therapeutic potential.

Depression and eating disorders: treatment and course

BACKGROUND

We examined the course of major depressive disorder (MDD) and predictors of MDD recovery and relapse in a longitudinal sample of women with eating disorders (ED).

METHODS

246 Boston-area women with DSM-IV anorexia nervosa-restricting (ANR; n=51), AN-binge/purge (ANBP; n=85), and bulimia nervosa (BN; n=110) were recruited between 1987 and 1991 and interviewed using the Eating Disorders Longitudinal Interval Follow-up Evaluation (LIFE-EAT-II) every 6-12 months for up to 12 years. 100 participants had MDD at study intake and 45 developed MDD during the study. Psychological functioning and treatment were assessed.

RESULTS

Times to MDD onset (1 week-4.3 years), recovery (8 weeks-8.7 years), and relapse (1 week-5.2 years) varied. 70% recovered from MDD, but 65% subsequently relapsed. ANR patients were significantly less likely to recover from MDD than ANBP patients (p=0.029). Better psychological functioning and history of MDD were associated with higher chance of MDD recovery. Higher baseline depressive severity and full recovery from ED were associated with greater likelihood of MDD relapse; increased weight loss was somewhat protective. Adequate antidepressant treatment was given to 72% of patients with MDD and generally continued after MDD recovery. Time on antidepressants did not predict MDD recovery (p=0.27) or relapse (p=0.26).

LIMITATIONS

Small ED diagnostic subgroups; lack of non-ED control group.

CONCLUSIONS

The course of MDD in EDs is protracted; MDD recovery may depend on ED type. Antidepressants did not impact likelihood of MDD recovery, nor protect against relapse, which may impact on treatment strategies for comorbid MDD and EDs.

Identification and management of eating disorders in children and adolescents

The incidence and prevalence of eating disorders in children and adolescents has increased significantly in recent decades, making it essential for pediatricians to consider these disorders in appropriate clinical settings, to evaluate patients suspected of having these disorders, and to manage (or refer) patients in whom eating disorders are diagnosed. This clinical report includes a discussion of diagnostic criteria and outlines the initial evaluation of the patient with disordered eating. Medical complications of eating disorders may affect any organ system, and careful monitoring for these complications is required. The range of treatment options, including pharmacotherapy, is described in this report. Pediatricians are encouraged to advocate for legislation and policies that ensure appropriate services for patients with eating disorders, including medical care, nutritional intervention, mental health treatment, and care coordination.

Functional variants of the serotonin receptor type 3A and B gene are associated with eating disorders

OBJECTIVE

As a key player in modulating both human physiological and behavioural functions including anxiety, perception and in particular appetite, serotonin (5-hydroxytryptamine, 5-HT) is likely to be involved in the aetiology of eating disorders. Studies showing serotonin receptor type 3 (5-HT3) receptors to mediate food intake depression (anorexic response) have triggered our interest in investigating the putative role of variants in the 5-HT3 receptor genes, HTR3A and HTR3B, in the susceptibility to anorexia nervosa (AN) and bulimia nervosa (BN).

METHODS

Two hundred and sixty-five patients with AN and 91 patients with BN as well as 191 healthy controls served as a pilot study group for mutational analysis by direct sequencing. Variants showing a significant association were subsequently genotyped in an independent Spanish cohort of 78 patients with AN and 119 patients with BN as well as 331 healthy controls for replication purposes.

RESULTS

In the pilot study, we found the coding HTR3B variant, p.Y129S, (rs1176744, P = 0.004, odds ratio = 2.06) to be associated with the restrictive subtype of AN. The association was confirmed in the Spanish study group (P = 0.034, odds ratio = 2.26).

CONCLUSION

Our study provides first evidence for an involvement of 5-HT3 variants in the aetiopathology of eating disorders in humans.

Abnormal eating attitudes in Mexican female students: a study of prevalence and sociodemographic-clinical associated factors

The objective of the study was to determine the prevalence of abnormal eating attitudes (AEA) in Mexican high school and university students in the city of San Luis Potosí, Mexico. By means of a transversal study with a weighted, random and multistage sampling process, we analyzed a representative sample of female students (N= 2006). The instrument was the Eating Disorder Inventory-2 (EDI-2), validated in Mexican population and a questionnaire of sociodemographic data. The prevalence of AEA was 12.6% and its frequency was significantly higher in high school than in university students. AEA cases were uniformly distributed among public and private institutions and a highly significant relationship between substances consumption and AEA was observed. A logistic regression model for AEA was obtained. Therefore, a profile of highly AEA was built based on sociodemographic data and a solid instrument validated in Mexican population, which can be employed as a screening and secondary prevention tool to design public health programs.

Role of antiepileptic drugs in the management of eating disorders

Growing evidence suggests that antiepileptic drugs (AEDs) may be useful in managing some eating disorders. In the present paper, we provide a brief overview of eating disorders, the rationale for using AEDs in the treatment of these disorders and review the data supporting the effectiveness of specific AEDs in the treatment of patients with eating disorders. In addition, the potential mechanisms of action of AEDs in these conditions are discussed. Of the available AEDs, topiramate appears to have the broadest spectrum of action as an anti-binge eating, anti-purging and weight loss agent, as demonstrated in two placebo-controlled studies in bulimia nervosa and three placebo-controlled studies in binge-eating disorder (BED) with obesity. Topiramate may also have beneficial effects in night-eating syndrome and sleep-related eating disorder, but controlled trials in these conditions are needed. The results of one small controlled study suggest that zonisamide may have efficacy in BED with obesity. However, both topiramate and zonisamide are associated with adverse effect profiles that may limit their use in patients with eating disorders. Phenytoin may be effective in some patients with compulsive binge eating, particularly if co-morbid EEG abnormalities are present, but available data are too varied to allow definitive conclusions to be made. Carbamazepine and valproate may be effective in treating patients with bulimia nervosa or anorexia nervosa when they are used to treat an associated psychiatric (e.g. mood) or neurological (e.g. seizure) disorder; otherwise, both agents, particularly valproate, are associated with weight gain. In conclusion, AEDs have an emerging role in the management of some eating disorders.

Examination of association of genes in the serotonin system to autism

Autism is characterized as one of the pervasive developmental disorders, a spectrum of often severe behavioral and cognitive disturbances of early development. The high heritability of autism has driven multiple efforts to identify genetic variation that increases autism susceptibility. Numerous studies have suggested that variation in peripheral and central metabolism of serotonin (5-hydroxytryptamine) may play a role in the pathophysiology of autism. We screened 403 autism families for 45 single nucleotide polymorphisms in ten serotonin pathway candidate genes. Although genome-wide linkage scans in autism have provided support for linkage to various loci located within the serotonin pathway, our study does not provide strong evidence for linkage to any specific gene within the pathway. The most significant association (p = 0.0002; p = 0.02 after correcting for multiple comparisons) was found at rs1150220 (HTR3A) located on chromosome 11 ( approximately 113 Mb). To test specifically for multilocus effects, multifactor dimensionality reduction was employed, and a significant two-way interaction (p value = 0.01) was found between rs10830962, near MTNR1B (chromosome11; 92,338,075 bp), and rs1007631, near SLC7A5 (chromosome16; 86,413,596 bp). These data suggest that variation within genes on the serotonin pathway, particularly HTR3A, may have modest effects on autism risk.

Histamine in the nervous system

Histamine is a transmitter in the nervous system and a signaling molecule in the gut, the skin, and the immune system. Histaminergic neurons in mammalian brain are located exclusively in the tuberomamillary nucleus of the posterior hypothalamus and send their axons all over the central nervous system. Active solely during waking, they maintain wakefulness and attention. Three of the four known histamine receptors and binding to glutamate NMDA receptors serve multiple functions in the brain, particularly control of excitability and plasticity. H1 and H2 receptor-mediated actions are mostly excitatory; H3 receptors act as inhibitory auto- and heteroreceptors. Mutual interactions with other transmitter systems form a network that links basic homeostatic and higher brain functions, including sleep-wake regulation, circadian and feeding rhythms, immunity, learning, and memory in health and disease.

A randomized, double-blind trial comparing sertraline and fluoxetine 6-month treatment in obese patients with Binge Eating Disorder

Previous studies support the use of selective serotonin reuptake inhibitors (SSRIs), in overweight patients with Binge Eating Disorder (BED), but results are far from conclusive. Sertraline has been studied less extensively, and there have been a few studies concerning SSRIs that report follow-up data at more than 12 weeks of follow-up. The present study assesses the effectiveness of sertraline and fluoxetine over a period of 24 weeks in obese patients with BED (DSM-IV-TR). Forty-two obese outpatients were randomized and assigned to one of two different drug treatments: 22 were treated with sertraline (dose range: 100-200 mg/day) and 20 with fluoxetine (dose range: 40-80 mg/day). Subjects were assessed at baseline and at 8, 12, and 24 weeks of treatment for binge frequency, weight loss, and severity of psychopathology. No significant differences were found between the two treatments. After 8 weeks of treatment a significant improvement in the Binge Eating Scale score and a significant weight loss emerged. These results were maintained by responders (weigh loss of at least 5% of baseline weight) over 24 weeks. The results suggest that a 6-month treatment with SSRI may be an effective option to treat patients with BED.

Eating disorders: an overview of treatment responses and the potential impact of vulnerability genes and endophenotypes

Anorexia nervosa (AN), bulimia nervosa (BN) and binge-eating disorder (BED) are the three main eating disorders. Antidepressants, antipsychotics, anticonvulsants, prokinetic agents, opiate antagonists, appetite suppressants, tetrahydrocannabinol, cyproheptadine, zinc and ondansetron have been tested, and are frequently associated with psychological treatment. Selective serotonin reuptake inhibitors have a proven efficacy in BN and binge eating disorder. Other treatments, such as atypical antipsychotics in AN, anticonvulsants in BN and BED, and naltrexone and ondansetron in BN, may be promising, but lack the appropriate trials. The development of genetic researches in eating disorders may help the clinician to choose the most appropriate treatment in forthcoming years, using genetic polymorphisms of vulnerability genes, those linked to endophenotypes, or genes implicated in the metabolism of the drug treatment.