Microbiota, Immune System and Autism Spectrum Disorders: An Integrative Model towards Novel Treatment Options

IUPHAR review: Targeted therapies of signaling pathways based on the gut microbiome in autism spectrum disorders: Mechanistic and therapeutic applications

Autism spectrum disorders (ASD) are complex neurodevelopmental disorders characterized by impairments in social interaction, communication and repetitive activities. Gut microbiota significantly influences behavior and neurodevelopment by regulating the gut-brain axis. This review explores gut microbiota-influenced treatments for ASD, focusing on their therapeutic applications and mechanistic insights. In addition, this review discusses the interactions between gut microbiota and the immune, metabolic and neuroendocrine systems, focusing on crucial microbial metabolites including short-chain fatty acids (SCFAs) and several neurotransmitters. Furthermore, the review explores various therapy methods including fecal microbiota transplantation, dietary modifications, probiotics and prebiotics and evaluates their safety and efficacy in reducing ASD symptoms. The discussion shows the potential of customized microbiome-based therapeutics and the integration of multi-omics methods to understand the underlying mechanisms. Moreover, the review explores the intricate relationship between gut microbiota and ASD, aiming to develop innovative therapies that utilize the gut microbiome to improve the clinical outcomes of ASD patients. Microbial metabolites such as neurotransmitter precursors, tryptophan metabolites and SCFAs affect brain development and behavior. Symptoms of ASD are linked to changes in these metabolites. Dysbiosis in the gut microbiome may impact neuroinflammatory processes linked to autism, negatively affecting immune signaling pathways. Research indicates that probiotics and prebiotics can improve gut microbiota and alleviate symptoms in ASD patients. Fecal microbiota transplantation may also improve behavioral symptoms and restore gut microbiota balance. The review emphasizes the need for further research on gut microbiota modification as a potential therapeutic approach for ASD, highlighting its potential in clinical settings.

Exploring the relationship among hikikomori tendencies, autistic traits, computer game use and eating disorder symptoms

OBJECTIVE

The hikikomori phenomenon has recently gained growing global interest, and evidences of its association with other psychopathological dimensions are slowly but steadily emerging. We aimed to evaluate the presence and correlates of hikikomori tendencies in an Italian University population, focusing on its relationships with autism spectrum, pathological computer gaming, and eating disorders. In particular, to our knowledge, no study has yet systematically evaluated the latter association, using psychometric instruments tailored to assess eating disorder symptoms.

METHODS

2574 students were recruited via an online survey. All participants were assessed with the Hikikomori Questionnaire-25 (HQ-25), the Adult Autism Subthreshold Spectrum Questionnaire (AdAS Spectrum), the Eating Attitude test-26 (EAT-26), and the Assessment of Internet and Computer Game Addiction (AICA-S).

RESULTS

The results outlined how hikikomori risk was significantly correlated to autistic dimensions, altered eating behaviors, and videogame addiction. The closest relationship was detected with the autism spectrum. Interestingly, pathological computer gaming, most autistic dimensions, and EAT-26 oral control emerged as significant predictors of a greater risk for hikikomori, while the proneness to inflexibility and adherence to routine emerged as negative predictors.

CONCLUSIONS

Our findings support the association among hikikomori, autism spectrum, pathological computer game use, and eating disorder symptoms.

Autistic traits are associated with the presence of post-traumatic stress symptoms and suicidality among subjects with autism spectrum conditions and Anorexia nervosa

INTRODUCTION

Recently, growing attention has been paid to the presence of undetected Autism Spectrum Disorder (ASD) and subthreshold autistic traits (ATs) among females, and on their gender specific manifestation. In particular, the recent literature focused on the overlap between autism spectrum and eating disorders, which share with ASD not only features such as of cognitive inflexibility but also a link with trauma- and stress-related disorders. In this framework, we aimed to assess the interaction between ATs, stress- or trauma-related symptoms, and the risk of suicidality in subjects with different mental conditions.

METHODS

184 subjects were divided in three diagnostic groups: Broad autism phenotype (BAP), Anorexia Nervosa (AN) and Healthy Controls (HCs) and assessed with the Adult Autism Subthreshold Spectrum (AdAS Spectrum) questionnaire, the Trauma and Loss Spectrum - Self Report (TALS - SR) questionnaire and the Mood Spectrum - Self Report (MOODS - SR) questionnaire.

RESULTS

AN subjects reported notable ATs reinforcing the hypothesis that AN might represent an atypical ASD manifestation more common in women. Furthermore, both AN and BAP subjects showed a considerable presence of trauma/stress associated symptoms. The dimension of trauma/stress related symptoms also appeared to be associated with ATs, and to significantly mediate the relationship between ATs and suicidality risk. Lastly, AN were found to have a stronger correlation with the presence of post-traumatic stress symptoms.

CONCLUSIONS

the results support the presence of a link between ATs and AN. Moreover, AN seems to be more strongly associated with post-traumatic stress symptoms than BAP. ATs and trauma/stress related symptoms may interact in shaping suicidality risk in these patients.

Autistic traits as predictors of post-traumatic stress symptoms among patients with borderline personality disorder

Background

Autistic traits (AT) seem to be particularly frequent among patients with borderline personality disorder (BPD). Moreover, the autism spectrum is considered a vulnerability factor for the development of post-traumatic stress disorder (PTSD) symptoms, increasing the vulnerability of BPD subjects toward the development of a stress-related disorder.

Aim

The study aimed to investigate the association between AT and trauma-related symptoms in a clinical sample of patients with BPD.

Methods

A total of 48 patients with a clinical diagnosis of BPD and 52 healthy control (HC) subjects were recruited and assessed with the Adult Autism Subthreshold Spectrum Self-Report (AdAS Spectrum) questionnaire and the Trauma and Loss Spectrum-Self-Report questionnaire (TALS-SR). The BPD group was divided into two subgroups: BPD with a symptomatological diagnosis of PTSD (pBPD = 25) and BPD not diagnosed with PTSD (No-pBPD = 23).

Results

The clinical sample scored significantly higher in almost all AdAS domains. Moreover, pBPD groups reported higher AdAS and TALS-SR scores in the total and in various domains than the No-pBPD group, which scored higher in several domains than HC. AdAS Restricted interests and rumination domain scores were positive predictors of BPD presence independently from PTSD, while Inflexibility and adherence to routine domain was a negative predictor. Finally, AdAS Hyper/hyporeactivity to sensory stimuli domain was a positive predictor only for inclusion in the pBPD group.

Conclusion

Our study confirmed the existence of a statistically significant relationship between the autism spectrum and BPD, while BPD subjects diagnosed with PTSD seem to show a higher autism spectrum burden.

Assessing Autistic Traits, Hikikomori Tendencies, Pathological Videogaming, and Eating Disorders in University Students: Are Pathological Videogaming and Eating Disorders Gender-Specific Manifestations of the Autism Spectrum?

In the previous literature, specific attention has been paid to investigate autism spectrum symptoms and traits in university students. In this framework, we aimed to evaluate the presence and correlates of autistic traits, hikikomori tendencies, altered eating behaviors, and pathological videogaming in a sample of Italian university students enrolled in bachelor's degree courses. A total of 1192 students were recruited via an online survey and assessed with the Hikikomori Questionnaire-25, the Adult Autism Subthreshold Spectrum Questionnaire, the Eating Attitude test-26, and the Assessment of Internet and Computer Game Addiction. Our results highlighted significant differences in the prevalence of autistic traits, social withdrawal tendencies, altered eating habits, and pathological videogame use in university students based on gender, age, parents' level of instruction, and field of study. A significant effect of the presence of autistic traits and gender on the scores obtained with the other questionnaires was reported. Our results not only support the role of autistic traits as a vulnerability factor for the development of a set of psychopathological conditions but also suggest that gender could modulate this vulnerability, supporting the hypothesis of gender-specific phenotypes in the autism spectrum.

Platelet Levels of Brain-Derived Neurotrophic Factor in Adults with Autism Spectrum Disorder: Is There a Specific Association with Autism Spectrum Psychopathology?

To date, although several studies have investigated the circulating levels of brain-derived neurotrophic factor (BDNF) in children with autism spectrum disorder (ASD), only a few authors have addressed their evaluation in adults. Furthermore, an important limitation of these studies lies in the fact that circulating BDNF is stored in platelets and released into the circulation when needed. To the best of our knowledge, a very limited number of studies have related peripheral BDNF values to platelet counts, and yet no study has evaluated intra-platelet BDNF levels in adults with ASD. In this framework, the aim of the present work is to pave the way in this field and evaluate platelet BNDF levels in adult ASD patients, as well as their correlation with autistic symptoms and related psychopathological dimensions. We recruited 22 ASD and 22 healthy controls, evaluated with the Adult autism subthreshold spectrum (AdAS Spectrum), the Social Anxiety Spectrum-self report (SHY-SR), the Trauma and loss spectrum-self report (TALS-SR), the Work and Social Adjustment Scale (WSAS), and the Mood Spectrum-self report for suicidality. Intra-platelet BDNF levels were also assessed. The results highlighted lower BDNF levels in the ASD group; moreover, AdAS Spectrum and WSAS total score as well as AdAS Spectrum Restricted interest and rumination, WSAS Private leisure activities, TALS-SR Arousal, and SHY-SR Childhood domains were significant negative predictors of platelet BDNF levels.

Case report: hikikomori syndrome in Italy and its link with autistic traits and internet gaming disorder

During the last few decades, a growing field of literature is focusing on hikikomori, a phenomenon described as a form of pathological social withdrawal or social isolation that lasts for more than 6 months leading to significant functional impairment and/or distress. Despite initially considered a culture-bound syndrome, hikikomori syndrome later gained a wider recognition in different countries, ranging from an attempt to take refuge in an idealistic world, when society success' standards are not reached, to a maladaptive coping strategy complicating several psychiatric illnesses such as anxiety disorders, major depression, internet addiction, internet gaming disorder (IGD) and autism spectrum disorder (ASD). In this framework, difficulties in social interaction, in problem solving strategies and socio-emotional reciprocity, may lead to social withdrawal and hikikomori-like behaviors. In this work, we described two cases of patients where the presence of underlying autism spectrum may have represented a sign of vulnerability towards the development of a possible full-blown case of hikikomori with IGD.

Rumination and altered reactivity to sensory input as vulnerability factors for developing post-traumatic stress symptoms among adults with autistic traits

OBJECTIVE

Recent literature has suggested that individuals with autism spectrum disorder (ASD) or autistic traits (ATs) would be more likely to encounter traumatic events in their lifetime and to develop post-traumatic stress disorder (PTSD). However, the nature of this relationship has not yet been fully elucidated. The aims of this study were to evaluate the relationship between AT and PTSD and to investigate which specific autistic dimension was more associated with trauma and stress-related symptoms.

METHODS

A total of 68 subjects with ASD and 64 healthy controls (HCs) were assessed with the Adult Autism Subthreshold Spectrum (AdAS Spectrum) and the Trauma and Loss Spectrum (TALS) questionnaires. Statistical analyses included Mann-Whitney U test, chi-square test, calculation of Spearman's coefficients, and logistic regression analysis.

RESULTS

Patients with significant AT reported a 30% rate of PTSD and higher TALS total and domain scores than HCs, among whom no PTSD was found instead. Significant positive correlations were reported between AdAS Spectrum and TALS-SR scores in the whole sample. AdAS Spectrum total scores were statistically predictive of the presence of PTSD. High scores at AdAS Spectrum Inflexibility and adherence to routine and Restrictive interest and rumination domains were identified as positive predictors of a probable PTSD.

CONCLUSION

Compared to HCs, subjects with significant AT are more likely to present symptoms of PTSD. In particular, AT related to ruminative thinking, narrow interests, and sensorial reactivity would seem to predict the presence of post-traumatic stress symptomatology.

Presence and correlates of autistic traits among patients with social anxiety disorder

Introduction

Due to their similar behavioral presentation, it can sometimes be challenging to distinguish between a social anxiety disorder (SAD) and the social avoidance that is frequently described in autism spectrum disorder (ASD). Moreover, a growing body of evidences is reporting that a significant proportion of subjects with ASD also meet the requirements for SAD and, vice versa, subjects with SAD tend to exhibit a higher prevalence of autistic traits.

Aim

In this framework, the current study aims to evaluate prevalence and correlates of autistic traits in a sample of adult subjects diagnosed with SAD and healthy controls (HC), also evaluating which autism spectrum dimensions may statistically predict higher SAD symptoms.

Methods

56 subjects with a clinical diagnosis of SAD and 56 gender and age matched HC were recruited from the Psychiatric Clinic of the University of Pisa. Subjects were assessed with the SCID-5, the Social Anxiety Spectrum - Short Version (SHY- SV) and the Adult Autism Subthreshold Spectrum (AdAS Spectrum).

Results

SAD group scored significantly higher in all AdAS Spectrum and SHY-SV domains and total score compared to the HC group with no significant gender difference. SHY-SV total and domain scores, were strongly and positively and strongly correlated with all AdAS Spectrum domains and total score. AdAS Spectrum total score and Childhood/Adolescence, Non-Verbal Communication, Empathy and Restricted interests and Rumination domain scores score were significant predictors of higher SHY-SV score.

Conclusion

Our results confirm the link between SAD and autistic traits also in adult population, describing not only high levels of autistic traits in SAD adults, but also significant correlations between many core features of the two disorders and a predictive role of autistic traits on higher SAD symptoms.

Cadmium exposure exacerbates immunological abnormalities in a BTBR T+ Itpr3tf/J autistic mouse model by upregulating inflammatory mediators in CD45R-expressing cells

Autism spectrum disorder (ASD) is a neurodevelopmental illness characterized by behavior, learning, communication, and social interaction abnormalities in various situations. Individuals with impairments usually exhibit restricted and repetitive actions. The actual cause of ASD is yet unknown. It is believed, however, that a mix of genetic and environmental factors may play a role in its development. Certain metals have been linked to the development of neurological diseases, and the prevalence of ASD has shown a positive association with industrialization. Cadmium chloride (Cd) is a neurotoxic chemical linked to cognitive impairment, tremors, and neurodegenerative diseases. The BTBR T+ Itpr3tf/J (BTBR) inbred mice are generally used as a model for ASD and display a range of autistic phenotypes. We looked at how Cd exposure affected the signaling of inflammatory mediators in CD45R-expressing cells in the BTBR mouse model of ASD. In this study, we looked at how Cd affected the expression of numerous markers in the spleen, including IFN-γ, IL-6, NF-κB p65, GM-CSF, iNOS, MCP-1, and Notch1. Furthermore, we investigated the effect of Cd exposure on the expression levels of numerous mRNA molecules in brain tissue, including IFN-γ, IL-6, NF-κB p65, GM-CSF, iNOS, MCP-1, and Notch1. The RT-PCR technique was used for this analysis. Cd exposure increased the number of CD45R+IFN-γ+, CD45R+IL-6+, CD45R+NF-κB p65+, CD45R+GM-CSF+, CD45R+GM-CSF+, CD45R+iNOS+, and CD45R+Notch1+ cells in the spleen of BTBR mice. Cd treatment also enhanced mRNA expression in brain tissue for IFN-γ, IL-6, NF-κB, GM-CSF, iNOS, MCP-1, and Notch1. In general, Cd increases the signaling of inflammatory mediators in BTBR mice. This study is the first to show that Cd exposure causes immune function dysregulation in the BTBR ASD mouse model. As a result, our study supports the role of Cd exposure in the development of ASD.

Autistic Traits as Predictors of Increased Obsessive-Compulsive Disorder Severity: The Role of Inflexibility and Communication Impairment

Due to similar manifestations, some authors have proposed a potential correlation between autism spectrum disorder (ASD) and obsessive-compulsive disorder (OCD). This link has long been recognized and debated, with some authors arguing that these disorders frequently occur comorbid but distinct while others believe they are part of the same spectrum. The aim of our study was to explore the prevalence and correlates of autistic traits in 55 OCD patients and 55 matched controls and to assess possible autistic dimensions predictive of higher OCD symptoms. All participants were assessed with the Obsessive-Compulsive Spectrum-Short Version (OBS-SV) and the Adult Autism Subthreshold Spectrum (AdAS Spectrum). The OCD group scored significantly higher in both questionnaires. Total OBS-SV scores and domains were significantly correlated with all AdAS Spectrum domains and total score. The AdAS Spectrum total, Verbal Communication and Inflexibility and adherence to routine domain scores were significant positive predictors of higher OBS-SV scores. Lastly, when two clusters of subjects (high and low autism) were determined, Inflexibility and adherence to routine domain presented the greatest influence in forming the clusters. Our findings support the association between OCD and autistic traits in the adult population, supporting the hypothesis of a neurodevelopmental basis for these psychiatric conditions.

May Female Autism Spectrum Be Masked by Eating Disorders, Borderline Personality Disorder, or Complex PTSD Symptoms? A Case Series

Introduction: The prevalence of Autism Spectrum Disorder (ASD) is four times higher in males than females; however, females are significantly more likely to go undiagnosed due to the existence of a "female autistic phenotype", a manifestation unique to females that conflicts with conventional, masculine conceptualizations of ASD. Furthermore, subthreshold autistic traits, which exert a significantly negative impact on quality of life and represent a vulnerability factor for the development of other psychopathological conditions, may remain even more under-recognized. Subsequently, many women with ASD may never receive a diagnosis or any resulting care, with serious consequences for their health. Aims: We aimed to describe two brief cases in order to confirm the diagnostic difficulties that ASD female undergo during their clinical evaluation and the possible alternative phenotype that they can manifest. Methods: We reported the cases of two young women on the autism spectrum that came to clinical attention only after the development of severe symptomatology attributed to other mental disorders, overlooking the presence of underlying autism spectrum features and a brief résumé of the literature on this topic. Results: These cases confirm the need for a timely and proper identification of females on the autism spectrum in order to prevent complications and improve the outcome. Conclusions: Research on gender differences could lead to a reexamination of the sex ratio in the prevalence of ASD and provide a better understanding of several psychiatric conditions that are frequently diagnosed in women, supporting the neurodevelopmental approach to psychopathology.

Implications of Social Anxiety Symptoms in Adults with Autism Spectrum Disorder: Is There a Predictive Role of Interpersonal Sensitivity and Substance Abuse?

Social anxiety disorder (SAD) has been frequently reported by subjects with Autism Spectrum Disorder (ASD). However, interestingly, the overlap between social anxiety and autistic traits may sometimes impede ASD diagnosis in subjects without intellectual or language impairment. The aim of the present work was to evaluate the presence and correlates of social phobic features among subjects with ASD, with a specific focus on evaluating which social anxiety symptoms may be statistically predictive of an ASD diagnosis. With this purpose, 48 subjects with ASD and 48 gender- and age- matched healthy controls (HCs) were recruited and assessed with the SHY-SV and the AdAS Spectrum questionnaires. Results highlighted higher scores in all SHY-SV Spectrum domains and total scores for the ASD group. Moreover, AdAS Spectrum scores were significantly correlated with all SHY-SV domain and total scores. A logistic regression analysis highlighted the SHY-SV Interpersonal sensitivity and Substance Abuse domains scores as significant positive predictors of an ASD diagnosis. These results confirm the link between ASD and SAD. Because of this association, particular attention should be paid to subjects with high interpersonal sensitivity traits and substance abuse problems.

IL-6, homocysteine, and autism spectrum phenotypes: an investigation among adults with autism spectrum disorder and their first-degree relatives

BACKGROUND

The importance of recognizing different kinds of autism spectrum presentations among adults, including subthreshold forms and the broad autism phenotype (BAP), has been increasingly highlighted in recent studies. Meanwhile, the possible involvement of immune system deregulation and altered methylation/trans-sulfuration processes in autism spectrum disorder (ASD) is gaining growing attention, but studies in this field are mainly focused on children. In this framework, the aim of this study was to compare plasmatic concentrations of IL-6 and homocysteine (HCY) among adults with ASD, their first-degree relatives, and healthy controls (CTLs), investigating also possible correlations with specific autism symptoms.

METHODS

Plasma concentrations of IL-6 and HCY were measured in a group of adult subjects with ASD, their first-degree relatives (BAP group), and healthy controls (CTL). All participants were also evaluated with psychometric instruments.

RESULTS

IL-6 and HCY concentrations were significantly higher in the ASD group than in CTLs, while BAP subjects reported intermediate results. Significant correlations were reported between biochemical parameters and psychometric scales, particularly for the dimension of ruminative thinking.

CONCLUSIONS

These findings support the hypothesis of a key involvement of HCY-related metabolism and immune system alteration in autism spectrum pathophysiology. HCY and IL-6 seem to show different associations with specific autism dimensions.

Unlocking the Secrets: Exploring the Biochemical Correlates of Suicidal Thoughts and Behaviors in Adults with Autism Spectrum Conditions

Involving 1 million people a year, suicide represents one of the major topics of psychiatric research. Despite the focus in recent years on neurobiological underpinnings, understanding and predicting suicide remains a challenge. Many sociodemographical risk factors and prognostic markers have been proposed but they have poor predictive accuracy. Biomarkers can provide essential information acting as predictive indicators, providing proof of treatment response and proposing potential targets while offering more assurance than psychological measures. In this framework, the aim of this study is to open the way in this field and evaluate the correlation between blood levels of serotonin, brain derived neurotrophic factor, tryptophan and its metabolites, IL-6 and homocysteine levels and suicidality. Blood samples were taken from 24 adults with autism, their first-degree relatives, and 24 controls. Biochemical parameters were measured with enzyme-linked immunosorbent assays. Suicidality was measured through selected items of the MOODS-SR. Here we confirm the link between suicidality and autism and provide more evidence regarding the association of suicidality with increased homocysteine (0.278) and IL-6 (0.487) levels and decreased tryptophan (-0.132) and kynurenic acid (-0.253) ones. Our results suggest a possible transnosographic association between these biochemical parameters and increased suicide risk.

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.

Measuring Social Camouflaging in Individuals with High Functioning Autism: A Literature Review

In the recent years, growing attention has been paid to the use of camouflaging strategies by adult populations suffering from autism spectrum disorder (ASD) with milder manifestations and without intellectual impairment, which may lead to a delay in diagnosis or even a misdiagnosis. In fact, high-functioning ASD individuals were reported to be more aware of their communication difficulties and were more likely make considerable efforts to adjust their behavior to conventional rules of non-autistic individuals, learning to imitate other non-ASD individuals. Moreover, females reported a higher frequency of camouflaging strategies, suggesting a role of camouflaging in the gender gap of the ASD diagnosis. Although camouflaging strategies can sometimes grant a better level of adjustment, even resulting in a hyper-adaptive behavior, they are also often correlated with negative mental health consequences due to the long-term stress associated with continuous attempts to adapt in day-to-day life. In this framework, the aim of the present work was to review the available studies that assessed the presence and correlates of camouflaging strategies in individuals with ASD. Although the literature available on the topic is still scarce, some interesting correlations between camouflaging and anxious and depressive symptoms, as well as suicidality, were highlighted. In particular, the controversial and sometime opposite thoughts and results about camouflaging may be clarified and integrated in light of a dimensional approach to psychopathology.

Biological Correlates of Post-Traumatic Growth (PTG): A Literature Review

Since the beginning of medical science, much research have focused on the psychopathological effects of traumatic experiences. Despite in past centuries the scientific literature on mental health has been mainly focused on the harmful effects of traumatic occurrences, more recently the idea of "post-traumatic growth" emerged, on the basis of a growing interest in the characteristics of resilience and possible positive consequences of trauma. In this framework, increasing attention is now being paid to the psychological meaning of PTG, with a consistent number of psychopathological and epidemiological studies on this subject, but limited literature focused on neurobiological correlates or eventual biomarkers of this condition. The present work aimed to summarize and review the available evidence on neurobiological correlates of PTG and their psychological and clinical meaning. Results highlighted a variety of biochemical and neurobiological differences between PTG and non-PTG individuals, partially corroborating findings from earlier research on post-traumatic stress disorder (PTSD). However, although promising, findings in this field are still too limited and additional studies on the neurobiological correlates of traumatic experiences are needed in order to gain a better understanding of the subject.

Altered gut microbiota correlates with behavioral problems but not gastrointestinal symptoms in individuals with autism

BACKGROUND

Despite inconsistent results across studies, emerging evidence suggests that the microbial micro-environment may be associated with autism spectrum disorder (ASD). Geographical and cultural factors highly impact microbial profiles, and there is a shortage of data from East Asian populations. This study aimed to comprehensively characterize microbial profiles in an East Asian sample and explore whether gut microbiota contributes to clinical symptoms, emotional/behavioral problems, and GI symptoms in ASD.

METHODS

We assessed 82 boys and young men with ASD and 31 typically developing controls (TDC), aged 6-25 years. We analyzed the stool sample of all participants with 16S V3-V4 rRNA sequencing and correlated its profile with GI symptoms, autistic symptoms, and emotional/behavioral problems.

RESULTS

Autistic individuals, compared to TDC, had worse GI symptoms. There were no group differences in alpha diversity of species richness estimates (Shannon-wiener and Simpson diversity indices). Participants with ASD had an increased relative abundance of Fusobacterium, Ruminococcus torques group (at the genus level), and Bacteroides plebeius DSM 17135 (at the species level), while a decreased relative abundance of Ruminococcaceae UCG 013, Ervsipelotrichaceae UCG 003, Parasutterella, Clostridium sensu stricto 1, Turicibacter (at the genus level), and Clostridium spiroforme DSM 1552 and Intestinimonas butyriciproducens (at the species level). Altered taxonomic diversity in ASD significantly correlated with autistic symptoms, thought problems, delinquent behaviors, self dysregulation, and somatic complaints. We did not find an association between gut symptoms and gut microbial dysbiosis.

CONCLUSIONS

Our findings suggest that altered microbiota are associated with behavioral phenotypes but not GI symptoms in ASD. The function of the identified microbial profiles mainly involves the immune pathway, supporting the hypothesis of a complex relationship between altered microbiome, immune dysregulation, and ASD that may advance the discovery of molecular biomarkers for ASD.

Autism Spectrum Disorder and Fetal Alcohol Spectrum Disorder: A Literature Review

Fetal alcohol spectrum disorders (FASD) are a group of conditions associated with the effects of prenatal alcohol exposure and characterized by somatic and neuropsychological alterations. On the other hand, autism spectrum disorder (ASD) is characterized by a multifaceted neurobehavioral syndrome. Since alcohol can affect every stage of brain development, some authors hypothesized that in utero alcohol exposure might be linked to an increased risk of ASD in subjects with genetic vulnerability. The present review aimed to summarize the available literature on the possible association between FASD and ASD, also focusing on the reported clinical overlaps and on the possible shared pathogenic mechanisms. Studies in this field have stressed similarities and differences between the two conditions, leading to controversial results. The available literature also highlighted that both the disorders are often misdiagnosed or underdiagnosed, stressing the need to broaden the perspective, paying specific attention to milder presentations and sub-syndromic traits.

Kynurenine pathway and autism spectrum phenotypes: an investigation among adults with autism spectrum disorder and their first-degree relatives

BACKGROUND

Increasing literature highlighted alterations of tryptophan (TRP) metabolism and kynurenine (KYN) pathway in children with autism spectrum disorder (ASD). However, no study specifically focused on adult samples. Meanwhile, several authors stressed the relevance of investigating neurobiological correlates of adult forms of ASD and of those subthreshold ASD manifestations frequently found in relatives of ASD probands, known as broad autism phenotype (BAP). This work aimed to evaluate circulating levels of TRP and metabolites of KYN pathway in a sample of ASD adults, their first-degree relatives and controls (CTLs), investigating also the correlations between biochemical variables' levels and ASD symptoms.

METHODS

A sample of ASD adults, together with a group of first-degree relatives (BAP group) and unrelated CTLs were assessed by means of psychometric scales. Circulating levels of TRP, KYN, quinolinic acid (QA), and kynurenic acid (KYNA) were assessed in all subjects.

RESULTS

ASD patients reported significantly higher total scores than the other groups on all psychometric scales. BAP subjects scored significantly higher than CTLs. ASD patients reported significantly lower TRP levels than BAP and CTL groups. Moreover, significantly lower levels of KYNA were reported in both ASD and BAP groups than in CTLs. Specific patterns of associations were found between autism symptoms and biochemical variables.

CONCLUSIONS

Our findings confirm in adult samples the presence of altered TRP metabolism through KYN pathway. The intermediate alterations reported among relatives of ASD patients further stress the presence of a continuum between subthreshold and full-threshold ASD phenotypes also from a biochemical perspective.

Anti-ganglioside M1 autoantibodies in Egyptian children with autism: a cross-sectional comparative study

Background

Autism may be one of the pediatric autoimmune neuropsychiatric disorders, and several studies investigated the frequency of serum anti-ganglioside M1 autoantibodies in children with autism, as possible indicators of autoimmunity to the brain. The current study aimed to compare the level of anti-ganglioside M1 autoantibodies between autistic and normally developed children and to study the correlation between the level of anti-ganglioside M1 autoatibodies and the severity of autism. Forty children with autism and 40 age- and gender-matched healthy controls were enrolled. The Childhood Autism Rating Scale was used to assess the severity of autism in the patient group at the time of the study. The clinical and demographic data were recorded and plasma anti-ganglioside M1 autoantibodies level was measured in both groups.

Results

The mean anti-ganglioside M1 autoantibodies level was significantly higher in autistic patients compared to the control group. The anti-ganglioside M1 autoantibodies level in patients with mild to moderate severity was insignificantly lower than its level in patients with severe autism.

Conclusions

Plasma anti-ganglioside MI autoantibodies levels are higher in autistic patients than in healthy controls which may imply that some cases of autism may be autoimmune in nature.

Biological correlates of altered circadian rhythms, autonomic functions and sleep problems in autism spectrum disorder

Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by a complex and multifaceted neurobehavioral syndrome. In the last decades, several studies highlighted an increased prevalence of sleep problems in ASD, which would be associated with autonomic system and circadian rhythm disruption. The present review aimed to summarize the available literature about sleep problems in ASD subjects and about the possible biological factors implicated in circadian rhythm and autonomic system deregulation in this population, as well as possible therapeutic approaches. Shared biological underpinnings between ASD symptoms and altered circadian rhythms/autonomic functions are also discussed. Studies on sleep showed how ASD subjects typically report more problems regarding insufficient sleep time, bedtime resistance and reduced sleep pressure. A link between sleep difficulties and irritability, deficits in social skills and behavioral problems was also highlighted. Among the mechanisms implicated, alteration in genes related to circadian rhythms, such as CLOCK genes, and in melatonin levels were reported. ASD subjects also showed altered hypothalamic pituitary adrenal (HPA) axis and autonomic functions, generally with a tendency towards hyperarousal and hyper sympathetic state. Intriguingly, some of these biological alterations in ASD individuals were not associated only with sleep problems but also with more autism-specific clusters of symptoms, such as communication impairment or repetitive behaviors Although among the available treatments melatonin showed promising results, pharmacological studies for sleep problems in ASD need to follow more standardized protocols to reach more repeatable and reliable results. Further research should investigate the issue of sleep problems in ASD in a broader perspective, taking into account shared pathophysiological mechanisms for core and associated symptoms of ASD.

Validation of the Italian version of the Camouflaging Autistic Traits Questionnaire (CAT-Q) in a University population

The Camouflaging Autistic Traits Questionnaire (CAT-Q) is an instrument recently developed and validated in English for measuring social camouflaging. While increasing research is focusing on camouflaging behaviours often used for masking autistic traits in social contexts, the CAT-Q remains the only self-report instrument in this field. We aimed to validate the Italian version of the CAT-Q, further testing its validity and reliability in a large Italian University population (N = 2439). We employed the Adult Autism Subthreshold Spectrum (AdAS Spectrum) for assessing autism spectrum conditions. The CAT-Q demonstrated excellent internal consistency and test-retest reliability, as well as strong correlations with the AdAS Spectrum. Our results confirm that the CAT-Q is a valuable instrument for evaluating social camouflaging.

Gut Microbiome-Based Analysis of Lipid A Biosynthesis in Individuals with Autism Spectrum Disorder: An In Silico Evaluation

The link between autism spectrum disorder (ASD) and the gut microbiome has received much attention, with special focus on gut–brain-axis immunological imbalances. Gastrointestinal problems are one of the major symptoms of ASD and are thought to be related to immune dysregulation. Therefore, in silico analysis was performed on mined data from 36 individuals with ASD and 21 control subjects, with an emphasis on lipid A endotoxin-producing bacteria and their lipopolysaccharide (LPS) metabolic pathways. Analysis of enzyme distribution among the 15 most abundant genera in both groups revealed that almost all these genera utilized five early-stage enzymes responsible for catalyzing the nine conserved lipid A synthesis steps. However, Haemophilus and Escherichia, which were significantly more abundant in individuals with ASD than in the control subjects, possess a complete set of essential lipid A synthesis enzymes. Furthermore, the 10 genera with the greatest increase in individuals with ASD showed high potential for producing late-stage lipid A products. Collectively, these results suggested that the synthesis rate of immunogenic LPS end products is likely to increase in individuals with ASD, which may be related to their gastrointestinal symptoms and elevated inflammatory conditions.

Defining the Optimal Threshold Scores for Adult Autism Subthreshold Spectrum (AdAS Spectrum) in Clinical and General Population

Background:

The Adult Autism Subthreshold Spectrum (AdAS Spectrum) is a recently developed instrument tailored to assess the broad range of full-threshold as well as sub-threshold manifestations related to the autism spectrum. Although it has proved to be a valuable instrument for quantitative assessment of autistic symptoms, the AdAS Spectrum still lacks validated diagnostic thresholds.

Objective:

The aim of this study was to define the best cut-off scores of the AdAS Spectrum for determining the presence of subthreshold autistic traits as well as a clinically significant autism spectrum disorder (ASD).

Methods:

Our sample was composed of 39 patients with full-blown ASD, 73 subjects with autistic traits, and 150 healthy controls. Subjects were evaluated by trained psychiatrists, who performed a clinical diagnosis according to DSM-5 and then assessed with the AdAS Spectrum and the Autism Spectrum Quotient.

Results:

Our results showed that the most discriminant cut-off scores were 70 for identifying subjects with full-blown ASD, and 43 for determining the presence of significant autistic traits.

Conclusion:

The threshold values proposed here showed satisfying levels of specificity and sensibility, as well as a good agreement with the diagnosis according to DSM-5 criteria, confirming the validity of the AdAS Spectrum as a psychometric tool for measuring ASD-related conditions in the clinical and general population.

Subthreshold Autism Spectrum in a Patient with Anorexia Nervosa and Behçet's Syndrome

Recently, increasing research stressed the presence of subthreshold autistic traits in patients with other psychiatric conditions. In this framework, a significant relationship between anorexia nervosa (AN) and the autism spectrum has been frequently reported, in particular among female samples, to the point that AN has been hypothesized to be a female phenotype of autism spectrum disorder (ASD). On the other hand, among subjects with ASD has been reported a higher prevalence of immune diseases and altered immune functions. While these reports seem to support an association between neurodevelopmental and immune system alterations in ASD, the relationship between the immune system and the broader autism spectrum, including its subthreshold manifestations, remains poorly investigated. In this report, we described the presence of autistic traits in a male inpatient with AN and separation anxiety disorder, who also show a diagnosis of Behçet's syndrome (BS). This case seems to further stress the association between AN and the autism spectrum, which may not be limited to the female gender. Moreover, it further suggests a deeper link between neurodevelopmental and immune system alterations. Implications are discussed in light of the more recent neurobiological and psychopathological hypothesis about the autism spectrum.

Subthreshold Autism Spectrum in a Patient with Anorexia Nervosa and Behçet's Syndrome

Recently, increasing research stressed the presence of subthreshold autistic traits in patients with other psychiatric conditions. In this framework, a significant relationship between anorexia nervosa (AN) and the autism spectrum has been frequently reported, in particular among female samples, to the point that AN has been hypothesized to be a female phenotype of autism spectrum disorder (ASD). On the other hand, among subjects with ASD has been reported a higher prevalence of immune diseases and altered immune functions. While these reports seem to support an association between neurodevelopmental and immune system alterations in ASD, the relationship between the immune system and the broader autism spectrum, including its subthreshold manifestations, remains poorly investigated. In this report, we described the presence of autistic traits in a male inpatient with AN and separation anxiety disorder, who also show a diagnosis of Behçet's syndrome (BS). This case seems to further stress the association between AN and the autism spectrum, which may not be limited to the female gender. Moreover, it further suggests a deeper link between neurodevelopmental and immune system alterations. Implications are discussed in light of the more recent neurobiological and psychopathological hypothesis about the autism spectrum.

Autistic Traits and Illness Trajectories

In the framework of increasing attention towards autism-related conditions, a growing number of studies have recently investigated the prevalence and features of sub-threshold Autistic Traits (ATs) among adults. ATs span across the general population, being more pronounced in several clinical groups of patients affected by psychiatric disorders. Moreover, ATs seem to be associated with specific personality features in non-clinical population, implying both a higher vulnerability towards psychopathology and extraordinary talents in specific fields. In this framework, the DSM-5’s Autism Spectrum Disorder (ASD) presentations may be considered as the tip of an iceberg that features several possible clinical and non-clinical phenotypes. Globally, the autism spectrum may be considered as a trans-nosographic dimension, which may not only represent the starting point for the development of different psychopathological trajectories but also underlie non-psychopathological personality traits. These different trajectories might be shaped by the specific localization and severity of the neurodevelopmental alteration and by its interaction with the environment and lifetime events. In this wider framework, autistic-like neurodevelopmental alterations may be considered as a general vulnerability factor for different kinds of psychiatric disorders, but also the neurobiological basis for the development of extraordinary abilities, eventually underlying the concept of geniality. Moreover, according to recent literature, we hypothesize that ATs may also be involved in the functioning of human mind, featuring the peculiar sense of “otherness” which can be found, with different grades of intensity, in every human being.