Is anorexia nervosa a neuropsychiatric developmental disorder? An illustrative case report

Autistic traits distribution in different psychiatric conditions: A cluster analysis on the basis of the Adult Autism Subthreshold Spectrum (AdAS Spectrum) questionnaire

Increasing interest is being paid on full-threshold and sub-threshold autism spectrum conditions among adults. Sub-threshold autistic traits (AT) seem to be distributed in a continuum from the clinical to the general population, being particularly higher among subjects with other psychiatric disorders. The aim of the present study was to evaluate the distribution of AT in a sample of subjects with different psychiatric conditions by means of a cluster analysis on the basis of the score reported to the AdAS Spectrum instrument. A total of 738 subjects recruited by seven Italian Universities were divided in 5 groups depending on the clinical diagnosis: Autism spectrum disorder (ASD), subthreshold ASD symptoms (partial ASD), Bipolar disorder (BD), Feeding and eating disorders (FED), and controls (CTLs). All subjects were assessed with the AdAS Spectrum. The cluster analysis identified 3 clusters: the high, medium and low autism clusters. The Restricted interests and rumination domain reported the highest influence in forming the clusters. The high, medium and low autism clusters were respectively more represented in the ASD, partial ASD and CTL groups. The clusters were represented intermediately in the FED and BD groups, confirming the presence of intermediate levels of AT in these clinical populations.

Modelling the neurodevelopmental pathogenesis in neuropsychiatric disorders. Bioactive kynurenines and their analogues as neuroprotective agents-in celebration of 80th birthday of Professor Peter Riederer

Following introduction of the monoamine oxidase type B inhibitor selegiline for the treatment of Parkinson's disease (PD), discovery of the action mechanism of Alzheimer's disease-modifying agent memantine, the role of iron in PD, and the loss of electron transport chain complex I in PD, and development of the concept of clinical neuroprotection, Peter Riederer launched one of the most challenging research project neurodevelopmental aspects of neuropsychiatric disorders. The neurodevelopmental theory holds that a disruption of normal brain development in utero or during early life underlies the subsequent emergence of neuropsychiatric symptoms during later life. Indeed, the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition and the International Classification of Diseases, 11th Revision categorize autism spectrum disorder and attention deficit hyperactivity disorder in neurodevelopmental disorders (NDDs). More and more evidence, especially from preclinical studies, is revealing that neurodevelopmental pathology is not limited to the diagnostic class above, but also contributes to the development of other psychiatric disorders such as schizophrenia, bipolar disorder, and obsessive-compulsive disorder as well as neurodegenerative diseases such as PD and Huntington's disease. Preclinical animal research is taking a lead in understanding the pathomechanisms of NDDs, searching for novel targets, and developing new neuroprotective agents against NDDs. This narrative review discusses emerging evidence of the neurodevelopmental etiology of neuropsychiatric disorders, recent advances in modelling neurodevelopmental pathogenesis, potential strategies of clinical neuroprotection using novel kynurenine metabolites and analogues, and future research direction for NDDs.

Caregiver Report of Executive Functioning in Adolescent Females With Anorexia Nervosa or Autism Spectrum Disorder

Current literature suggesting a shared endophenotype between individuals with anorexia nervosa (AN) and autism spectrum disorder (ASD) related to executive functioning (EF) has several limitations: performance-based instead of ecologically valid measures of set-shifting are used, lack of comparisons between same-sex groups, and reliance on adult samples only. This was the first study directly comparing female youth with ASD to female youth with AN using an ecologically valid measure of EF. A secondary data analysis combined caregiver-reported EF on the Behavior Rating Inventory of Executive Functioning (BRIEF) for 22 female adolescent youth with AN and 29 female adolescent youth with ASD. EF in each group was compared to population norms, and EF was compared between groups. Compared to population norms, adolescents with AN had elevated scores on shift, initiate, and emotional control scales, and adolescents with ASD had elevated scores on all scales of the BRIEF and were more likely to have scores in the clinical range. There were significant differences between groups on all but three scales. The cognitive profiles and clinical scores of AN females were not comparable to those of ASD females. The findings reveal a clear clinical impairment in females with ASD but not in females with AN. The results do not support the hypothesis of similar real-world EF profiles between these groups. The results encourage further exploration into the similarities and distinctions between these two disorders.

Endophenotypes: A conceptual link between anorexia nervosa and autism spectrum disorder

The paper, by translating the concept and the two models of endophenotype (EP), strengthens the hypothesis that there exists a linkage between anorexia nervosa (AN) and autism spectrum disorder (ASD). Specifically, the paper synthesizes empirical research that supported the idea that individuals with AN and individuals with ASD share similarities with respect to their neurocognitive EPs and temperament EPs. The paper then introduces an innovative structure to emphasize the subtle difference between neurocognitive EPs and temperament EPs in relation to AN and ASD. This structure constitutes the categorization of the shared neurocognitive EPs to the liability-index model of EP and the shared temperament EPs to the mediational model of EP. The paper argues that the shared neurocognitive EPs under the liability index model of EP are trait markers signaling the effects of genes on the phenotypes of AN and ASD; whereas, the shared temperament EPs under the mediational model of EP are state markers describing the symptomatic status of AN and ASD. The proposition of the paper suggests clinicians and researchers should target the atypical state markers (i.e., temperament EPs) shared between AN and ASD when tailoring environment-based treatments for individuals with AN who exhibit autistic behaviors and individuals with ASD who display disordered eating behaviors or anorexic symptoms.

Subthreshold autism spectrum disorder in patients with eating disorders

AIM

Increasingly data suggest a possible overlap between psychopathological manifestations of eating disorders (EDs) and autism spectrum disorders (ASD). The aim of the present study was to assess the presence of subthreshold autism spectrum symptoms, by means of a recently validated instrument, in a sample of participants with EDs, particularly comparing participants with or without binge eating behaviours.

METHODS

138 participants meeting DSM-5 criteria for EDs and 160 healthy control participants (HCs), were recruited at 3 Italian University Departments of Psychiatry and assessed by the SCID-5, the Adult Autism Subthreshold Spectrum (AdAS Spectrum) and the Eating Disorders Inventory, version 2 (EDI-2). ED participants included: 46 with restrictive anorexia (AN-R); 24 with binge-purging type of Anorexia Nervosa (AN-BP); 34 with Bulimia Nervosa (BN) and 34 with Binge Eating Disorder (BED). The sample was split in two groups: participants with binge eating behaviours (BEB), in which were included participants with AN-BP, BN and BED, and participants with restrictive behaviours (AN-R).

RESULTS

participants with EDs showed significantly higher AdAS Spectrum total scores than HCs. Moreover, EDs participants showed significantly higher scores on all AdAS Spectrum domains with the exception of Non verbal communication and Hyper-Hypo reactivity to sensory input for AN-BP participants, and Childhood/Adolescence domain for AN-BP and BED participants. Participants with AN-R scored significantly higher than participants with BEB on the AdAS Spectrum total score, and on the Inflexibility and adherence to routine and Restricted interest/rumination AdAS Spectrum domain scores. Significant correlations emerged between the Interpersonal distrust EDI-2 sub-scale and the Non verbal communication and the Restricted interest and rumination AdAS Spectrum domains; as well as between the Social insecurity EDI-2 sub-scale and the Inflexibility and adherence to routine and Restricted interest and rumination domains in participants with EDs.

CONCLUSIONS

Our data corroborate the presence of higher subthreshold autism spectrum symptoms among ED participants with respect to HCs, with particularly higher levels among restrictive participants. Relevant correlations between subthreshold autism spectrum symptoms and EDI-2 Subscale also emerged.

Enteric short-chain fatty acids: microbial messengers of metabolism, mitochondria, and mind: implications in autism spectrum disorders

Clinical observations suggest that gut and dietary factors transiently worsen and, in some cases, appear to improve behavioral symptoms in a subset of persons with autism spectrum disorders (ASDs), but the reason for this is unclear. Emerging evidence suggests ASDs are a family of systemic disorders of altered immunity, metabolism, and gene expression. Pre- or perinatal infection, hospitalization, or early antibiotic exposure, which may alter gut microbiota, have been suggested as potential risk factors for ASD. Can a common environmental agent link these disparate findings? This review outlines basic science and clinical evidence that enteric short-chain fatty acids (SCFAs), present in diet and also produced by opportunistic gut bacteria following fermentation of dietary carbohydrates, may be environmental triggers in ASD. Of note, propionic acid, a major SCFA produced by ASD-associated gastrointestinal bacteria (clostridia, bacteroides, desulfovibrio) and also a common food preservative, can produce reversible behavioral, electrographic, neuroinflammatory, metabolic, and epigenetic changes closely resembling those found in ASD when administered to rodents. Major effects of these SCFAs may be through the alteration of mitochondrial function via the citric acid cycle and carnitine metabolism, or the epigenetic modulation of ASD-associated genes, which may be useful clinical biomarkers. It discusses the hypothesis that ASDs are produced by pre- or post-natal alterations in intestinal microbiota in sensitive sub-populations, which may have major implications in ASD cause, diagnosis, prevention, and treatment.

Early-onset anorexia nervosa in girls with Asperger syndrome

Eating disorders frequently occur in conjunction with autism spectrum disorders, posing diagnostic and therapeutic difficulties. The comorbidity of anorexia nervosa and Asperger syndrome is a significant clinical complication and has been associated with a poorer prognosis. The authors are presenting the cases of an eleven-year-old girl and a five-and-a-half-year-old girl with comorbid eating disorders and Asperger syndrome.

Autism: metabolism, mitochondria, and the microbiome

New approaches are needed to examine the diverse symptoms and comorbidities of the growing family of neurodevelopmental disorders known as autism spectrum disorder (ASD). ASD originally was thought to be a static, inheritable neurodevelopmental disorder, and our understanding of it is undergoing a major shift. It is emerging as a dynamic system of metabolic and immune anomalies involving many organ systems, including the brain, and environmental exposure. The initial detailed observation and inquiry of patients with ASD and related conditions and the histories of their caregivers and families have been invaluable. How gastrointestinal (GI) factors are related to ASD is not yet clear. Nevertheless, many patients with ASD have a history of previous antibiotic exposure or hospitalization, GI symptoms, abnormal food cravings, and unique intestinal bacterial populations, which have been proposed to relate to variable symptom severity. In addition to traditional scientific inquiry, detailed clinical observation and recording of exacerbations, remissions, and comorbidities are needed. This article reviews the role that enteric short-chain fatty acids, particularly propionic (also called propanoic) acid, produced from ASD-associated GI bacteria, may play in the etiology of some forms of ASD. Human populations that are partial metabolizers of propionic acid are more common than previously thought. The results from pre-clinical laboratory studies show that propionic acid-treated rats display ASD-like repetitive, perseverative, and antisocial behaviors and seizure. Neurochemical changes, consistent and predictive with findings in ASD patients, including neuroinflammation, increased oxidative stress, mitochondrial dysfunction, glutathione depletion, and altered phospholipid/acylcarnitine profiles, have been observed. Propionic acid has bioactive effects on (1) neurotransmitter systems, (2) intracellular acidification and calcium release, (3) fatty acid metabolism, (4) gap junction gating, (5) immune function, and (6) alteration of gene expression that warrant further exploration. Traditional scientific experimentation is needed to verify the hypothesis that enteric short-chain fatty acids may be a potential environmental trigger in some forms of ASD. Novel collaborative developments in systems biology, particularly examining the role of the microbiome and its effects on host metabolism, immune and mitochondrial function, and gene expression, hold great promise in ASD.

Short-chain fatty acid fermentation products of the gut microbiome: implications in autism spectrum disorders

Recent evidence suggests potential, but unproven, links between dietary, metabolic, infective, and gastrointestinal factors and the behavioral exacerbations and remissions of autism spectrum disorders (ASDs). Propionic acid (PPA) and its related short-chain fatty acids (SCFAs) are fermentation products of ASD-associated bacteria (Clostridia, Bacteriodetes, Desulfovibrio). SCFAs represent a group of compounds derived from the host microbiome that are plausibly linked to ASDs and can induce widespread effects on gut, brain, and behavior. Intraventricular administration of PPA and SCFAs in rats induces abnormal motor movements, repetitive interests, electrographic changes, cognitive deficits, perseveration, and impaired social interactions. The brain tissue of PPA-treated rats shows a number of ASD-linked neurochemical changes, including innate neuroinflammation, increased oxidative stress, glutathione depletion, and altered phospholipid/acylcarnitine profiles. These directly or indirectly contribute to acquired mitochondrial dysfunction via impairment in carnitine-dependent pathways, consistent with findings in patients with ASDs. Of note, common antibiotics may impair carnitine-dependent processes by altering gut flora favoring PPA-producing bacteria and by directly inhibiting carnitine transport across the gut. Human populations that are partial metabolizers of PPA are more common than previously thought. PPA has further bioactive effects on neurotransmitter systems, intracellular acidification/calcium release, fatty acid metabolism, gap junction gating, immune function, and alteration of gene expression that warrant further exploration. These findings are consistent with the symptoms and proposed underlying mechanisms of ASDs and support the use of PPA infusions in rats as a valid animal model of the condition. Collectively, this offers further support that gut-derived factors, such as dietary or enteric bacterially produced SCFAs, may be plausible environmental agents that can trigger ASDs or ASD-related behaviors and deserve further exploration in basic science, agriculture, and clinical medicine.

Transient psychosis in anorexia nervosa: review and case report

Psychotic symptoms are a key feature in eating disorders. Restrictive-type anorectics are more prone to suffer them, coherent with recent neurocognitive findings reporting attentional and processing deficits in restrictive anorexia partially common to schizophrenia. Psychotic crises urge psychiatrists to make an accurate differential diagnosis with endogenous psychoses and carefully judge treatment options. If attentively attended, such crises can give us clues to understand the patient s functioning and consider new strategies. We report two transient psychotic episodes in restrictive-type anorectic female patients, one with a previous experience. Onset of psychotic symptoms was related to severe malnutrition only in one of them (body mass index <15). We discuss risk factors, clinical presentation and treatment, focusing on the emotional disturbances maintained after recovery. Causes for psychotic features in these patients are reviewed and treatment individually tailored. An integrative understanding of eating disorders as a unique meeting point between psychosis and neurosis is encouraged.