Neuroimaging Findings in Adolescents and Young Adults with Anorexia Nervosa: A Systematic Review

Anorexia nervosa in children and adolescents: an early detection of risk factors

The incidence of eating disorders in children, mainly of anorexia nervosa, is dramatically increased in the last years. A timely identification of the disease is associated with higher rates of recovery. Aim of the work is to underline signs and symptoms that can be used to an early detection of anorexia nervosa in the pediatric age. A scoping review has been conducted by The Italian Pediatric Society Adolescent Study Group according to the PRISMA Extension guidelines for Scoping Reviews, using the search term "anorexia nervosa" and the following filters "review", "systematic review", "age 0-18", "last 4 years". The strategy search produced 657 studies, of which 52 were included in this revision. Screening and red flags were discussed in 23 reports, genetics in 12, neurological pathways in 11, environmental factors in 10, and gut microbiota in 7. An accurate physiological and pathological anamnesis, physical and psychological examination, including the body perception, should be taken in account as well as the presence of co-morbidities, including chronic functional abdominal pain and autoimmune/autoinflammatory diseases. Evidence suggests the role of familiar predisposition as well as of neurological morphology and pathway in anorexia nervosa development. Gut microbiota has also been included among possible risk factor for developing anorexia nervosa due to a complex direct and indirect interactions between gut and brain. The Italian Pediatric Society Adolescent Study Group suggests performing an accurate familial and personal anamnesis, including psychological evaluation as well as a physical exam including auxological parameters as a screening tool during pediatric checks to better explore the risk of developing anorexia nervosa.

Neuroimaging studies of resting-state functional magnetic resonance imaging in eating disorders

Eating disorders (EDs), including anorexia nervosa (AN), bulimia nervosa (BN), binge-eating disorder (BED), and pica, are psychobehavioral conditions characterized by abnormal eating behaviors and an excessive preoccupation with weight and body shape. This review examines changes in brain regions and functional connectivity in ED patients over the past decade (2013-2023) using resting-state functional magnetic resonance imaging (rs-fMRI). Key findings highlight alterations in brain networks such as the default mode network (DMN), central executive network (CEN), and emotion regulation network (ERN). In individuals with AN, there is reduced functional connectivity in areas associated with facial information processing and social cognition, alongside increased connectivity in regions linked to sensory stimulation, aesthetic judgment, and social anxiety. Conversely, BED patients show diminished connectivity in the dorsal anterior cingulate cortex within the salience network and increased connectivity in the posterior cingulate cortex and medial prefrontal cortex within the DMN. These findings suggest that rs-fMRI could serve as a valuable biomarker for assessing brain function and predicting treatment outcomes in EDs, paving the way for personalized therapeutic strategies.

Associations between parental rearing style and amygdala and hippocampal subfield abnormalities in drug-naive females with anorexia nervosa

BACKGROUND

Altered volumes in the hippocampus and amygdala have been linked to anorexia nervosa (AN). This study aimed to investigate amygdala and hippocampal subfields volume abnormalities in AN patients, and their associations with parental rearing practices and clinical psychological characteristics.

METHODS

This study included twenty-nine drug-naive females with AN from West China Hospital of Sichuan University, China, and fifty-nine age- and gender-matched healthy controls (HCs) recruited through advertisement. All participants underwent T1-weighted imaging. Amygdala and hippocampal subfields volume was calculated using FreeSurfer 7.0. The Core Self-Evaluation Scale (CSES) and Rosenberg Self-Esteem Scale (RSES) were used to assess the psychological characteristics of AN patients. The Egna Minnen av Barndoms Uppfostran (EMBU) was employed to evaluate parental rearing practices. Group differences in brain volumes were analyzed with covariates like age and total intracranial volume (TIV). Partial correlation analysis explored the correlations between brain region volumes and clinical psychological characteristics.

RESULTS

AN patients exhibited lower RSES and CSES scores, and more adverse parental rearing style than healthy norms. After adjusting for covariates, AN patients showed decreased gray matter volume (GMV) in the left medial (Me) and cortical (Co) nucleus, as well as in the right hippocampal-amygdala transition area (HATA). GMV in the left Me was correlated with years of education among HCs but not among AN patients. GMV in the right HATA was positively correlated with paternal penalty and severity, as well as maternal overinterference.

CONCLUSION

This study supports structure abnormalities in amygdala and hippocampus in AN patients and suggests that parental rearing practices may be associated with hippocampal abnormalities, potentially contributing to the pathophysiology of AN. Addressing appropriate parental rearing styles may offer a positive impact on AN.

Anorexia Nervosa Across the Lifespan: A Review of Recent Literature

In this review, the authors provide an update on the understanding of anorexia nervosa (AN) across the lifespan. Focusing on key pieces of literature from the past 5 years, this review summarizes recent updates to DSM-5 within the domain of AN, including the addition of a new AN diagnosis: atypical anorexia. Additional sections covered in this review include improvements in the epidemiological understanding of AN across the developmental spectrum, treatment approaches that have been established as gold standard as well as new directions recently explored in treatment, and recent advancements in the biopsychosocial underpinnings of AN. Altogether, although this review captures several advancements in the field's overall conceptualization of AN, several key areas of treatment and diagnostic capacity continue to require additional focus and research.

Processing of food stimuli in anorexia nervosa: An ERP-study comparing adolescents and adults

BACKGROUND

Anorexia nervosa (AN) is associated with altered processing of disorder-relevant stimuli. Event-related potentials (ERP) - such as the Late Positive Potential (LPP) - give information about the underlying mechanisms of central nervous stimulus processing.

METHODS

Patients with AN (22 adolescents, 23 adults) and healthy controls (HCs; 17 adolescents, 24 adults) were included. Neutral, low, and high calorie food-images were rated for valence and arousal; EEG activity was recorded and LPPs (early: 350-700 ms; late: 800-1200 ms) were extracted. Effects of patient status, age group, and stimulus category were analyzed via mixed 2 × 2 × 3-AN(C)OVAs.

RESULTS

Patients with AN rated high calorie stimuli lower in valence and higher in arousal than HCs. Controlling for hunger, food stimuli elicited higher early LPPs than neutral ones in patients and HCs. For the late LPP, patients with AN showed larger amplitudes.

CONCLUSION

Results suggest a highly automatic attentional bias towards low-calorie foods. Patients with AN seem to have more intense cognitive processing independent of stimulus material. More research is needed to validate and clarify differences between early and late LPP measures as well as the operationalization and relevance of hunger status.

Mapping length of inpatient treatment duration and year-wise relapse rates in eating disordered populations in a well-defined Western-European healthcare region across 1998-2020

OBJECTIVES

Updated international guideline recommendations for AN inpatient care rely on expert opinions/observational evidence and promote extended inpatient stays, warranting investigation using higher-level ecological evidence.

METHODS

The study was conducted according to Guidelines for Accurate and Transparent Health Estimates Reporting (GATHER). Data encompassing 13,885 ED inpatients (5336 adolescents and 8549 adults) was retrieved from Swedish public health registries. Variables analyzed included (1) ED inpatient care opportunities, (2) unique number of ED inpatients and (3) mean length of ED-related inpatient stays in age groups 15-19 and 20-88+, across 1998-2020.

RESULTS

Mean length of inpatient stays was inversely correlated to relapse to ED-related inpatient care within the same year (p < 0.001, R-squaredadj  = 0.5216 and p < 0.00001, R-squaredadj  = 0.5090, in the 15-19 and 20-88+ age groups, respectively), independent of number of ED inpatients treated within a year in both age groups. Extending mean adolescent inpatient duration from 35 to 45 days was associated with a ∼30% reduction in the year-wise relapse rate.

CONCLUSIONS

Mean length of ED-related inpatient treatment stays was associated with reduced relapses to inpatient care within the same year, which could be interpreted as support for recommendations to include a stabilization phase in inpatient ED treatment.

Anorexia Nervosa With Comorbid Severe Depression: A Systematic Scoping Review of Brain Stimulation Treatments

ABSTRACT

Major depressive disorder (MDD) is highly prevalent in individuals with anorexia nervosa (AN) and is a predictor of greater clinical severity. However, there is a limited amount of evidence supporting the use of psychotropic medications for its management. A systematic scoping review was conducted to assess the current literature on brain stimulation treatments for AN with comorbid MDD, with a specific focus on MDD treatment response and weight restoration. This review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, and the PubMed, PsycInfo, and MEDLINE databases were searched until July 2022 using specific key words related to AN and brain stimulation treatments. A total of 373 citations were identified, and 49 treatment studies that met the inclusion criteria were included in the review. The initial evidence suggests that electroconvulsive therapy, repetitive transcranial magnetic stimulation, and deep-brain stimulation may be effective in managing comorbid MDD in AN. Emerging evidence suggests that transcranial direct current stimulation may have a positive effect on body mass index in individuals with severe to extreme AN. However, there is a need for the development of better measurement techniques for assessing the severity of depression in the context of AN. Controlled trials that are adequately designed to account for these limitations are highly warranted for deep-brain stimulation, electroconvulsive therapy, and repetitive transcranial magnetic stimulation and hold promise for providing clinically meaningful results.

Differential alterations of amygdala nuclei volumes in acutely ill patients with anorexia nervosa and their associations with leptin levels

BACKGROUND

The amygdala is a subcortical limbic structure consisting of histologically and functionally distinct subregions. New automated structural magnetic resonance imaging (MRI) segmentation tools facilitate the in vivo study of individual amygdala nuclei in clinical populations such as patients with anorexia nervosa (AN) who show symptoms indicative of limbic dysregulation. This study is the first to investigate amygdala nuclei volumes in AN, their relationships with leptin, a key indicator of AN-related neuroendocrine alterations, and further clinical measures.

METHODS

T1-weighted MRI scans were subsegmented and multi-stage quality controlled using FreeSurfer. Left/right hemispheric amygdala nuclei volumes were cross-sectionally compared between females with AN (n = 168, 12-29 years) and age-matched healthy females (n = 168) applying general linear models. Associations with plasma leptin, body mass index (BMI), illness duration, and psychiatric symptoms were analyzed via robust linear regression.

RESULTS

Globally, most amygdala nuclei volumes in both hemispheres were reduced in AN v. healthy control participants. Importantly, four specific nuclei (accessory basal, cortical, medial nuclei, corticoamygdaloid transition in the rostral-medial amygdala) showed greater volumetric reduction even relative to reductions of whole amygdala and total subcortical gray matter volumes, whereas basal, lateral, and paralaminar nuclei were less reduced. All rostral-medially clustered nuclei were positively associated with leptin in AN independent of BMI. Amygdala nuclei volumes were not associated with illness duration or psychiatric symptom severity in AN.

CONCLUSIONS

In AN, amygdala nuclei are altered to different degrees. Severe volume loss in rostral-medially clustered nuclei, collectively involved in olfactory/food-related reward processing, may represent a structural correlate of AN-related symptoms. Hypoleptinemia might be linked to rostral-medial amygdala alterations.

Investigation of brain iron in anorexia nervosa, a quantitative susceptibility mapping study

BACKGROUND

Anorexia nervosa (AN) is a potentially fatal psychiatric condition, associated with structural brain changes such as gray matter volume loss. The pathophysiological mechanisms for these changes are not yet fully understood. Iron is a crucial element in the development and function of the brain. Considering the systemic alterations in iron homeostasis in AN, we hypothesized that brain iron would be altered as a possible factor associated with structural brain changes in AN.

METHODS

In this study, we used quantitative susceptibility mapping (QSM) magnetic resonance imaging to investigate brain iron in current AN (c-AN) and weight-restored AN compared with healthy individuals. Whole-brain voxel wise comparison was used to probe areas with possible group differences. Further, the thalamus, caudate nucleus, putamen, nucleus accumbens, hippocampus, and amygdala were selected as the regions of interest (ROIs) for ROI-based comparison of mean QSM values.

RESULTS

Whole-brain voxel-wise and ROI-based comparison of QSM did not reveal any differences between groups. Exploratory analyses revealed a correlation between higher regional QSM (higher iron) and lower body mass index, higher illness severity, longer illness duration, and younger age at onset in the c-AN group.

CONCLUSIONS

This study did not find evidence of altered brain iron in AN compared to healthy individuals. However, the correlations between clinical variables and QSM suggest a link between brain iron and weight status or biological processes in AN, which warrants further investigation.

Can neuroimaging measures differentiate the disease course of anorexia nervosa? A systematic review

Anorexia nervosa (AN) entails many uncertainties regarding the clinical outcome, due to large heterogeneity in the disease course. AN is associated with global decrease in brain volumes and altered brain functioning during acute illness. However, it is unclear whether structural and functional brain alterations can predict clinical outcome. We aimed to systematically review the predictive value of volumetric and functional brain outcome measures of structural and functional brain magnetic resonance imaging (MRI) on the disease course of AN. Four databases (Embase, Medline, Psycinfo, and Cochrane Central Register) were systematically searched. A total of 15 studies (structural MRI: n = 6, functional MRI: n = 9) were reviewed. In total 464 unique AN patients, and 328 controls were included. Follow-up time ranged between 1 and 43 months. Structural neuroimaging studies showed that lower brain volumes of the cerebellum, subcortical grey matter, and cortical white matter at admission predicted a worse clinical outcome. A smaller increase of the anterior cingulate cortex volume in the early phase of the disease predicted a worse clinical outcome. Lower overall gyrification, and a higher clustering coefficient predicted a worse clinical outcome. Functional MRI studies showed that frontal, parietal and temporal activity during task-based algorithms predicted follow-up body mass index, although results were bidirectional possibly due to the large heterogeneity in methodological approaches. Neuroimaging measures may predict the clinical outcome of AN. However, there is a lack of replication studies. Future studies are needed to validate the prognostic utility of neuroimaging measures in AN patients, and should harmonize demographic, clinical and neuroimaging features in order to enhance comparability.

Unique considerations for the medical care of restrictive eating disorders in children and young adolescents

BACKGROUND

The medical complications of eating disorders are often approached through an age-neutral lens. However, children and young adolescents may have unique medical complications related to the energy needs and timing of growth and development. Providers caring for patients in this vulnerable age range should understand how to identify, approach, and manage these potential age-related complications.

REVIEW

Evidence continues to accumulate that increasingly younger patients are being diagnosed with eating disorders. These children and young adolescents have significant risk for unique and potentially irreversible medical complications. Without early identification and treatment, restrictive eating disorders may negatively impact linear growth, bone development and brain maturation in children and young adolescents. Additionally, due to the energy needs of growth and development, unique considerations exist for the use of acute medical stabilization and the identification of patients at risk for refeeding syndrome with initial nutritional rehabilitation. This review presents an approach to the evaluation and management of children and young adolescents with eating disorders.

CONCLUSION

Children and young adolescents with restrictive eating disorders may have unique medical complications related to the energy needs and timing of linear growth and pubertal development. Significant risk exists for irreversible medical complications of impaired growth, bone, and brain health. Increased awareness of the energy needs for growth and development may improve early recognition, appropriate intervention, and future outcomes for children and young adolescents with restrictive eating disorders.

A meta-analytic investigation of grey matter differences in anorexia nervosa and autism spectrum disorder

Recent research reports Anorexia Nervosa (AN) to be highly dependent upon neurobiological function. Some behaviours, particularly concerning food selectivity are found in populations with both Autism Spectrum Disorder (ASD) and AN, and there is a proportionally elevated number of anorexic patients exhibiting symptoms of ASD. We performed a systematic review of structural MRI literature with the aim of identifying common structural neural correlates common to both AN and ASD. Across 46 ASD publications, a meta‐analysis of volumetric differences between ASD and healthy controls revealed no consistently affected brain regions. Meta‐analysis of 23 AN publications revealed increased volume within the orbitofrontal cortex and medial temporal lobe, and adult‐only AN literature revealed differences within the genu of the anterior cingulate cortex. The changes are consistent with alterations in flexible reward‐related learning and episodic memory reported in neuropsychological studies. There was no structural overlap between ASD and AN. Findings suggest no consistent neuroanatomical abnormality associated with ASD, and evidence is lacking to suggest that reported behavioural similarities between those with AN and ASD are due to neuroanatomical structural similarities.

Findings related to neuroanatomical structure in AN/ASD demonstrate overlap and require revisiting.

Meta‐analytic findings show structural increase/decrease versus healthy controls (LPFC/MTL/OFC) in AN, but no clusters found in ASD.

The neuroanatomy associated with ASD is inconsistent, but findings in AN reflect condition‐related impairment in executive function and sociocognitive behaviours.

Initial evidence of abnormal brain plasticity in anorexia nervosa: an ultra-high field study

Anorexia Nervosa has been associated with white matter abnormalities implicating subcortical abnormal myelination. Extending these findings to intracortical myelin has been challenging but ultra-high field neuroimaging offers new methodological opportunities. To test the integrity of intracortical myelin in AN we used 7 T neuroimaging to acquire T1-weighted images optimized for intracortical myelin from seven females with AN (age range: 18-33) and 11 healthy females (age range: 23-32). Intracortical T₁ values (inverse index of myelin concentration) were extracted from 148 cortical regions at ten depth-levels across the cortical ribbon. Across all cortical regions, these levels were averaged to generate estimates of total intracortical myelin concentration and were clustered using principal component analyses into two clusters; the outer cluster comprised T₁ values across depth-levels ranging from the CSF boundary to the middle of the cortical regions and the inner cluster comprised T₁ values across depth-levels ranging from the middle of the cortical regions to the gray/white matter boundary. Individuals with AN exhibited higher T₁ values (i.e., decreased intracortical myelin concentration) in all three metrics. It remains to be established if these abnormalities result from undernutrition or specific lipid nutritional imbalances, or are trait markers; and whether they may contribute to neurobiological deficits seen in AN.

The Synergistic Effects of a Complementary Physiotherapeutic Scheme in the Psychological and Nutritional Treatment in a Teenage Girl with Type 1 Diabetes Mellitus, Anxiety Disorder and Anorexia Nervosa

Type 1 diabetes mellitus (T1DM) is a chronic disease that can affect the physical and mental health of children and adolescents, often leading to anxiety disorders with chronic activation of the hypothalamic axis (HPA). Moreover, a great proportion of adolescents with T1DM also demonstrate anorexia nervosa (AN), due to the increased preoccupation with food and the need to have an acceptable body image. Herein is described the first case study of an adolescent patient diagnosed with T1DM, anxiety disorder (AD), and AN. A 14-year-old girl with T1DM since the age of 12 years presented weight loss at age 13 years and 3 months and low body mass index (BMI), which did not improve despite dietary recommendations and adequate disease control. Additionally, she presented menstrual disorders at the age of 12 years and 11 months (menstrual age 12 years and 1 month). A psychological evaluation of the teenager was conducted using a semi-structured interview that assessed perceived stress, health status, quality of life, and depression. AD and AN were diagnosed and the patient initiated an intervention focusing on psychological health and nutrition and which incorporated physiotherapeutic relaxation sessions and breathing exercises. After 3 months of treatment, the patient’s BMI was increased, and a normal menstrual cycle was apparent. These results have since remained consistent. Stress leads to the appearance of AN and menstrual disorders. Therefore, physiotherapeutic programs could reduce stress and effectively ameliorate AN and AD.