Autism spectrum and obsessive-compulsive disorders: OC behaviors, phenotypes and genetics

Prevalence and Correlates of the Concurrence of Autism Spectrum Disorder and Obsessive Compulsive Disorder in Children and Adolescents: A Systematic Review and Meta-Analysis

BACKGROUND

Autism spectrum disorder (ASD) and obsessive compulsive disorder (OCD) are two common and impairing neurodevelopmental conditions with partial symptomatic overlap. The aim of this study is to systematically and meta-analytically examine the following: (i) the prevalence of an OCD diagnosis among young people with ASD, (ii) the prevalence of an ASD diagnosis among young people with OCD, and (iii) the clinical and therapeutic implications of such comorbidity.

METHOD

A multistep literature search was performed from database inception until 17 November 2023. This PRISMA/MOOSE-compliant systematic review, registered in PROSPERO (CRD42023480543), identified studies reporting on the prevalence, sociodemographic, psychopathologic, prognostic, and therapeutic correlates of OCD and ASD concurrence in children and adolescents. A quantitative meta-analysis with random effects was conducted to analyse the pooled prevalence of OCD among samples with a mean age of < 18 years old with ASD and the prevalence of ASD among individuals under 18 with OCD. Sensitivity analyses were performed to investigate the effect of diagnostic criteria and different continents. Meta-regression analyses were conducted to examine the effect of gender, age, IQ, and OCD severity scores. A narrative review of the clinical and therapeutical implications of the comorbidity was provided.

RESULTS

42 studies were selected for the systematic review (SR), and 31 of them were also included in one of the meta-analyses. The pooled prevalence of OCD among ASD youth samples (n = 8916, mean age = 10.6 ± 1.6; 16.4% female) was 11.6% (95% confidence intervals [CI] = 6.9%; 18.8%), and the pooled prevalence of ASD among OCD children and adolescent samples (n = 6209, mean age = 14.1 ± 1.4; 45.7% female) was 9.5% (95% CI = 6.0%; 14.7%). Meta-regressions found a statistically higher prevalence of ASD among samples with a lower prevalence of females (β = -4.7; 95%CI = -8.6; -0.8). Children with both OCD and ASD present higher rates of functional impairment, psychopathology, and other comorbidities, compared to youth with either of the disorders alone.

CONCLUSIONS

OCD and ASD are highly concurrent conditions in youth, with symptomatic, prognostic, severity, and therapeutic implications. Future research should focus on conducting longitudinal cohort studies prospectively to determine development trajectories, along with randomized controlled trials to assess the efficacy of specific therapeutic interventions.

Single-locus and Haplotype Associations of GRIN2B Gene with Autism Spectrum Disorders and the Demographic and Clinical Characteristics of Patients in Guilan, Iran

Autism spectrum disorders (ASDs) are described as generalized developmental disorders, with an average age of onset of 36 months. Genetic and environmental factors may contribute to this multifactorial disorder. The present study aimed to investigate the association of three GRIN2B polymorphisms, including rs1019385, rs1024893, and rs3764028, with ASDs. Based on the results, there was a significant difference regarding the genotype frequency of rs3764028 polymorphism between the control and case (ASD) groups (P = 0.027). According to the recessive model, this variant was associated with ASDs (P = 0.23). None of the eight haplotype models with frequencies above 0.5 showed significant differences between the case and control groups in terms of allelic frequency. The present results showed that the rs376028 variant was directly related to the phenotypic symptoms of ASDs.

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.

Effects of Augmented Reality Game-Based Cognitive-Motor Training on Restricted and Repetitive Behaviors and Executive Function in Patients with Autism Spectrum Disorder

Restricted and repetitive behaviors (RRBs) and executive dysfunction are widely acknowledged as core features and hallmarks in patients with autism spectrum disorder (ASD). This study aimed to investigate the effects of augmented reality (AR) using motivational games with cognitive–motor exercises on RRBs, executive function (EF), attention, and reaction time in patients with ASD. Twenty-four patients (range from 6 to 18 years) diagnosed with ASD were recruited from local social welfare centers and randomly allocated to the AR game-based cognitive–motor training group (study group) or the conventional cognitive training group (control group). Both groups completed 30 min training sessions, twice a week for four weeks. Outcome measures were conducted before and after the intervention. As a result, improvements were observed in all the subscales of the RRBs in the study group except for self-injurious and ritualistic behavior. Significant improvements were observed in EF and reaction time in the study group, which was significantly higher compared to the control group. With the present findings, we can suggest that cognitive–motor training using AR game-based content generates positive effects on improving executive function reaction time and accuracy of responses and has a limited effect on RRBs in patients with ASD. This can be proposed as a complementary intervention associated with individualized daily management.

The Clinical Implications of the Academic Performance of the Siblings of Individuals With Autism Spectrum Disorder

We all know that autism spectrum disorder (ASD) can affect academic performance. Many children with autism face different challenges at school. However, less attention is paid to the siblings of autistic children, who are at a high risk of ASD or the broad autism phenotype (BAP). Recent data also shows that many siblings of ASD children suffer from neurodevelopmental disorders, mental health problems as well as poor academic performance. This review will look at the possible etiologies of the poor school performance of autistic children's siblings, with an emphasis on the challenges they face. We will also highlight the clinical implications of these findings, and the possible solutions that can help this vulnerable group.

Pathophysiological Heterogeneity of the BBSOA Neurodevelopmental Syndrome

The formation and maturation of the human brain is regulated by highly coordinated developmental events, such as neural cell proliferation, migration and differentiation. Any impairment of these interconnected multi-factorial processes can affect brain structure and function and lead to distinctive neurodevelopmental disorders. Here, we review the pathophysiology of the Bosch–Boonstra–Schaaf Optic Atrophy Syndrome (BBSOAS; OMIM 615722; ORPHA 401777), a recently described monogenic neurodevelopmental syndrome caused by the haploinsufficiency of NR2F1 gene, a key transcriptional regulator of brain development. Although intellectual disability, developmental delay and visual impairment are arguably the most common symptoms affecting BBSOAS patients, multiple additional features are often reported, including epilepsy, autistic traits and hypotonia. The presence of specific symptoms and their variable level of severity might depend on still poorly characterized genotype–phenotype correlations. We begin with an overview of the several mutations of NR2F1 identified to date, then further focuses on the main pathological features of BBSOAS patients, providing evidence—whenever possible—for the existing genotype–phenotype correlations. On the clinical side, we lay out an up-to-date list of clinical examinations and therapeutic interventions recommended for children with BBSOAS. On the experimental side, we describe state-of-the-art in vivo and in vitro studies aiming at deciphering the role of mouse Nr2f1, in physiological conditions and in pathological contexts, underlying the BBSOAS features. Furthermore, by modeling distinct NR2F1 genetic alterations in terms of dimer formation and nuclear receptor binding efficiencies, we attempt to estimate the total amounts of functional NR2F1 acting in developing brain cells in normal and pathological conditions. Finally, using the NR2F1 gene and BBSOAS as a paradigm of monogenic rare neurodevelopmental disorder, we aim to set the path for future explorations of causative links between impaired brain development and the appearance of symptoms in human neurological syndromes.

The obsessive-compulsive spectrum: A network analysis

Several studies have shown that obsessive-compulsive disorder (OCD), eating disorders (ED), autism spectrum disorders (ASD) and body dysmorphic disorder (BDD) share obsessive-compulsive (OC) symptoms and often co-occur, which could be seen as indicative of a common etiological basis. In addition, they also appear to have similarities in executive functioning. The present study investigated disorder-specific symptoms and executive functioning as a possible joint factor in individuals with OCD (n=53), BDD (n=95), ED (n=171) and ASD (n=73), and in healthy controls (n=110). The participants completed online questionnaires measuring OCD, ED, ASD and BDD related symptoms as well as executive functioning. The clinical groups were first compared to the healthy controls. Subsequently, a network analysis was performed only with the OC-groups. This network approach assumes that psychopathological disorders are the result of causal symptom interactions. As expected, the healthy controls reported less severe symptoms compared to the OC patient groups. The network analysis suggested that the executive functioning skill set shifting/attention switching and the ASD symptoms, social and communication skills were the most central nodes in the model. Difficulty with cognitive flexibility and social factors are central in OC-spectrum disorders and may be perpetuating factors and thus a relevant focus of treatment.

Memantine treatment does not affect compulsive behavior or frontostriatal connectivity in an adolescent rat model for quinpirole-induced compulsive checking behavior

RATIONALE

Compulsivity often develops during childhood and is associated with elevated glutamate levels within the frontostriatal system. This suggests that anti-glutamatergic drugs, like memantine, may be an effective treatment.

OBJECTIVE

Our goal was to characterize the acute and chronic effect of memantine treatment on compulsive behavior and frontostriatal network structure and function in an adolescent rat model of compulsivity.

METHODS

Juvenile Sprague-Dawley rats received repeated quinpirole, resulting in compulsive checking behavior (n = 32; compulsive) or saline injections (n = 32; control). Eight compulsive and control rats received chronic memantine treatment, and eight compulsive and control rats received saline treatment for seven consecutive days between the 10th and 12th quinpirole/saline injection. Compulsive checking behavior was assessed, and structural and functional brain connectivity was measured with diffusion MRI and resting-state fMRI before and after treatment. The other rats received an acute single memantine (compulsive: n = 12; control: n = 12) or saline injection (compulsive: n = 4; control: n = 4) during pharmacological MRI after the 12th quinpirole/saline injection. An additional group of rats received a single memantine injection after a single quinpirole injection (n = 8).

RESULTS

Memantine treatment did not affect compulsive checking nor frontostriatal structural and functional connectivity in the quinpirole-induced adolescent rat model. While memantine activated the frontal cortex in control rats, no significant activation responses were measured after single or repeated quinpirole injections.

CONCLUSIONS

The lack of a memantine treatment effect in quinpirole-induced compulsive adolescent rats may be partly explained by the interaction between glutamatergic and dopaminergic receptors in the brain, which can be evaluated with functional MRI.

Innate Preferences Affect Results of Object Recognition Task in Wild Type and Alzheimer's Disease Mouse Models

BACKGROUND

Object recognition task (ORT) is a widely used behavioral paradigm to assess memory in rodent models, due to its easy technical execution, the lack of aversive stressful stimuli, and the possibility to repeat the test on the same animals. However, mouse exploration might be strongly influenced by a variety of variables.

OBJECTIVE

To study whether innate preferences influenced exploration in male and female wild type mice and the Alzheimer's disease (AD) model 3xTg.

METHODS

We first evaluated how object characteristics (material, size, and shape) influence exploration levels, latency, and exploration modality. Based on these findings, we evaluated whether these innate preferences biased the results of ORT performed in wild type mice and AD models.

RESULTS

Assessment of Exploration levels, i.e., the time spent in exploring a certain object in respect to the total exploration time, revealed an innate preference for objects made in shiny materials, such as metal and glass. A preference for bigger objects characterized by higher affordance was also evident, especially in male mice. When performing ORT, exploration was highly influenced by these innate preferences. Indeed, both wild type and AD mice spent more time in exploring the metal object, regardless of its novelty. Furthermore, the use of objects with higher affordance such as the cube was a confounding factor leading to "false" results that distorted ORT interpretation.

CONCLUSION

When designing exploration-based behavioral experiments aimed at assessing memory in healthy and AD mice, object characteristics should be carefully evaluated to improve scientific outcomes and minimize possible biases.

Obsessive-Compulsive Disorder in Autism Spectrum Disorder Across the Lifespan

Obsessive-compulsive disorder is a relatively common disorder seen in autism spectrum disorder across the lifespan. Many obsessive-compulsive disorder symptoms can present similarly to the core features of autism spectrum disorder and it is often difficult to differentiate between obsessive-compulsive disorder and stereotypic behaviors or restricted interests in autism spectrum disorder. However, there are differences between the 2 disorders. This article is a review of the current literature with the goal of helping the clinician to diagnose and treat obsessive-compulsive disorder in a patient with autism spectrum disorder.

Reduced DNA methylation of the oxytocin receptor gene is associated with obsessive-compulsive disorder

Background

Oxytocin is an important neuromodulator involved in cognition and socio-emotional processing that exerts its central activities via oxytocin receptors. Epigenetic alterations in the oxytocin receptor gene (OXTR) may be a molecular mechanism in the pathogenesis of obsessive-compulsive disorder (OCD). This study investigated the association between OXTR DNA methylation and the OCD status of a Korean population.

Results

Quantitative leukocyte DNA methylation levels of three cytosine-phosphate-guanine (CpG) sites in the 5′ untranslated region (UTR) of OXTR exon 2 and eight CpG sites within OXTR exon 3 were analyzed using the pyrosequencing method in 151 patients with OCD (including 45 drug-naïve patients) and 108 healthy controls. DNA methylation levels were compared between the groups using multiple analyses of covariance separately by sex after controlling for age and educational level. Patients with OCD showed significantly lower methylation levels at CpG1 and CpG2 sites on the UTR of OXTR exon 2 than those of healthy controls for both sexes. In a subset of 45 drug-naïve patients with OCD, the DNA methylation levels also remained significantly lower than those in the controls and their CpG1 methylation levels were significantly negatively associated with the ordering symptom dimension.

Conclusions

Our findings suggest that epigenetic OXTR alterations may affect the pathophysiology of OCD. The potential role of the oxytocin system in OCD development and treatment warrants further investigation.

Trait specific modulatory effects of caffeine exposure on compulsive-like behaviors in a spontaneous mouse model of obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a psychiatric disorder characterized by recurring intrusive thoughts and repetitive compulsive behaviors, ultimately interfering with their quality of life. The complex heterogeneity of symptom dimensions across OCD patient subgroups impedes diagnosis and treatment. The core and comorbid symptomologies of OCD are thought to be modulated by common environmental exposures such as consumption of the psychostimulant caffeine. The effect of caffeine on the expression of obsessions and compulsions are unexplored. The current study utilized mouse strains (HA) with a spontaneous, predictable, and stable compulsive-like phenotype that have face, predictive, and construct validity for OCD. We demonstrate that an acute high dose (25 mg/kg) of caffeine decreased compulsive-like nest-building behavior in the HA strains in the first hour after injection. However, nest-building scores increased in hours 3, 4, and 5 after administration finally decreasing over a 24 h period. In contrast, a high dose of chronic caffeine (25 mg/kg/d) increased nest-building behavior. Interestingly for compulsive-like digging behavior, acute exposure to a high dose of caffeine decreased the number of marbles buried, while chronic exposure had little effect. An acute high dose of caffeine decreased anxiety-like and motor activity in open field behaviors whereas chronic caffeine administration did not have any overall effect on open field activity. The results, therefore, suggest a complex role of caffeine on compulsive-like, anxiety-like, and locomotor behaviors that is dependent on the duration of exposure.

Obsessive-Compulsive Disorder in Autism Spectrum Disorder Across the Lifespan

Obsessive-compulsive disorder is a relatively common disorder seen in autism spectrum disorder across the lifespan. Many obsessive-compulsive disorder symptoms can present similarly to the core features of autism spectrum disorder and it is often difficult to differentiate between obsessive-compulsive disorder and stereotypic behaviors or restricted interests in autism spectrum disorder. However, there are differences between the 2 disorders. This article is a review of the current literature with the goal of helping the clinician to diagnose and treat obsessive-compulsive disorder in a patient with autism spectrum disorder.

Pharmacotherapy of restricted/repetitive behavior in autism spectrum disorder:a systematic review and meta-analysis

BACKGROUND

This paper is a systematic review and meta-analysis of the efficacy of available medications for the treatment of restricted/repetitive behavior (RRBs) in Autism Spectrum Disorder (ASD).

METHOD

We searched MEDLINE, Embase, PsycINFO, The Cochrane Library (Cochrane Database of Systematic Reviews (CDRS), the Cochrane Central Register of Controlled Trials (CENTRAL), database of Abstracts of Reviews of Effects (DARE)), Scopus, Epistimonikos, Clinicaltrials.gov, and included all randomized controlled trials published after 1993 that were directed at RRBs in patients with ASD of all ages. We extracted the relevant data from the published studies with a predefined data extraction form and assessed the risk of bias. The primary outcomes were change in restricted/repetitive behavior. We performed a meta-analysis using the random effect model and included studies with given mean and standard deviation. This study is registered with PROSPERO number CRD42018092660).

RESULTS

We identified 14 randomized controlled trials that met initial inclusion criteria. After closer inspection, nine trials - involving 552 patients in total - were included in the final analysis. The meta-analysis found no significant difference between medications (including fluvoxamine, risperidone, fluoxetine, citalopram, oxytocin, N-Acetylcysteine, buspirone) and placebo in the treatment of RRBs in ASD (P = 0.20). Similarly, the sub-group meta-analysis also showed no significant difference between Selective Serotonin Reuptake Inhibitor (SSRIs) and placebo in the treatment of RRBs in ASD (P = 0.68). There was no evidence of publication bias.

CONCLUSION

This meta-analysis finds little support for the routine use of medications to treat restricted/repetitive behaviors in Autism Spectrum Disorder. Further research of large, balanced trials with precise assessment tools and long-term follow-up are needed.

TRIAL REGISTRATION

The study protocol is registered in PROSPERO (Reference number: CRD42018092660).

Family Accommodation in Autism Spectrum Disorder

Family accommodation occurs frequently among families of children with OCD and anxiety disorders, with higher levels of accommodation repeatedly associated with greater symptom severity, lower functioning, and poorer treatment outcomes for children. This is the first examination of family accommodation of restricted and repetitive behaviors (RRBs) in children with autism spectrum disorder (ASD). Parents of children with ASD (N = 86) completed questionnaires assessing their children's RRBs and parental accommodation of these symptoms. Most participants (80%) reported engaging in accommodation at least once a month and family accommodation was significantly positively correlated with RRB severity. These results suggest accommodation of RRBs follows a pattern similar to that reported in obsessive compulsive and anxiety disorders, and highlight avenues for potential parent-based interventions.

Systematic Review: Overlap Between Eating, Autism Spectrum, and Attention-Deficit/Hyperactivity Disorder

Background: Links between eating disorders (EDs) [e.g., anorexia nervosa (AN), bulimia nervosa (BN), and binge eating disorder (BED)] and the major neurodevelopmental disorders of autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) have been repeatedly highlighted. In both ASD and ADHD, these links range from an elevated risk for EDs to common symptomatic overlaps and etiological commonalities with EDs. Methods: We performed a systematic literature search (through July 2019) with Medline via Ovid for epidemiological data on EDs (AN, BN, and BED) in combination with both ASD and ADHD. Results: The reviewed studies showed that, on average, 4.7% of patients with certain ED diagnoses (AN, BN, or BED) received an ASD diagnosis. Reliable data on the prevalence of EDs in ASD samples are still scarce. Comorbid ASD is most commonly diagnosed in patients with AN. The prevalence of ADHD in EDs ranged between 1.6% and 18%. Comorbid ADHD was more often reported in the AN-binge eating/purging subtype and BN than in the AN restrictive subtype. The prevalence of EDs in ADHD ranged between no association and a lifetime prevalence of 21.8% of developing an ED in women with ADHD. Conclusions: Studies on the prevalence rates of EDs in ADHD and ASD and vice versa are heterogeneous, but they indicate frequent association. While there is growing evidence of clinical overlaps between the three disorders, it remains difficult to determine whether overlapping characteristics (e.g., social withdrawal) are due to common comorbidities (e.g., depression) or are instead primarily associated with EDs and neurodevelopmental disorders. Furthermore, prospective studies are required to better understand how these disorders are related and whether ADHD and ASD could be either specific or nonspecific predisposing factors for the development of EDs.

The Effect of ASIC3 Knockout on Corticostriatal Circuit and Mouse Self-grooming Behavior

Stereotypic and/or repetitive behavior is one of the major symptoms of autism spectrum disorder (ASD). Increase of self-grooming behavior is a behavioral phenotype commonly observed in the mouse models for ASD. Previously, we have shown that knockout of acid-sensing ion channel 3 (ASIC3) led to the increased self-grooming behavior in resident-intruder test. Given the facts that ASIC3 is mainly expressed in the peripheral dorsal root ganglion (DRG) and conditional knockout of ASIC3 in the proprioceptors induced proprioception deficits. We speculate a hypothesis that stereotypic phenotype related to ASD, pararalled with striatal dysfunction, might be caused by proprioception defect in the peripheral sensory neuron origin. Herein, we investigate in depth whether and how ASIC3 is involved in the regulation of self-grooming behavior. First, we observed that Asic3 null mutant mice exhibited increased self-grooming in social interaction during juvenile stage. Similarly, they displayed increased self-grooming behavior in a novel cage in the absence of cagemate. To further understand the mechanism by which ASIC3 affects grooming behavior, we analyzed neurochemical, neuropathological and electrophysiological features in the dorsal striatum of Asic3 null mutant mice. Knockout of Asic3 increased dopamine (DA) activity and phospho-ERK immunoreactivities in the dorsal striatum. Furthermore, we detected a lower paired-pulse ratio (PPR) and impaired long-term potentiation (LTP) in corticostriatal circuits in Asic3 null mutant mice as compared with wild-type (WT) littermates. Moreover, knockout of Asic3 altered the medial spiny neurons in the striatum with defects in presynaptic function and decrease of dendritic spines. Lastly, genetic ablation of Asic3 specifically in parvalbumin-positive (PV⁺) cells resulted in the increase of self-grooming behavior in mice. These findings suggest knockout of Asic3 in the PV⁺ neurons alters grooming behavior by co-opting corticostriatal circuits.

Insistence on sameness and broader autism phenotype in simplex families with autism spectrum disorder

Insistence on sameness (IS) in individuals with autism spectrum disorder (ASD) and their families may have utility in identifying meaningful subgroups for studying the pathophysiological and genetic pathways affected in ASD. The primary objectives of the current study were to (1) characterize features of IS in parents of children with ASD and (2) examine their relationships with child IS symptoms. Participants were 2760 families who participated in the Simons Simplex Collection. Levels of parent IS were measured using the Broader Autism Phenotype Questionnaire (BAPQ). A factor analysis generated a BAPQ-IS scale, consisting of a subset of 11 items from the original BAPQ-Rigid scale. Correlations were run to examine the relationship between parent BAP and child IS variables. Correlations were found between parent IS and measures of child IS. Although relationships between parent and child IS features were statistically significant in this large sample, effect sizes were small. Results may be reflective of sample design that only included simplex families, where ASD severity may be predominantly driven by spontaneous mutations and less by common inherited risk from parents. In addition, child and parent measures used may have differentially captured features and severity of IS. Further research is needed on how IS can be accurately measured throughout development and across individuals with ASD and their unaffected family members to facilitate future studies on IS as a possible endophenotype for ASD. Autism Res 2018, 11: 1253-1263. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Previous research has suggested that insistence on sameness (IS) may be a heritable trait in autism spectrum disorder (ASD). The study examined whether children with high levels of IS had parents with IS tendencies. A small relationship was found between parent and child measures of IS. Future research is needed on measurement of insistence on sameness across individuals with and without ASD to further examine this relationship and improve understanding of the genetics of ASD.

Activation of Serotonin 5-HT7 Receptors Modulates Hippocampal Synaptic Plasticity by Stimulation of Adenylate Cyclases and Rescues Learning and Behavior in a Mouse Model of Fragile X Syndrome

We have previously demonstrated that activation of serotonin 5-HT₇ receptors (5-HT₇R) reverses metabotropic glutamate receptor-mediated long term depression (mGluR-LTD) in the hippocampus of wild-type (WT) and Fmr1 Knockout (KO) mice, a model of Fragile X Syndrome (FXS) in which mGluR-LTD is abnormally enhanced. Here, we have investigated intracellular mechanisms underlying the effect of 5-HT₇R activation using patch clamp on hippocampal slices. Furthermore, we have tested whether in vivo administration of LP-211, a selective 5-HT₇R agonist, can rescue learning and behavior in Fmr1 KO mice. In the presence of an adenylate cyclase blocker, mGluR-LTD was slightly enhanced in WT and therefore the difference between mGluR-LTD in WT and Fmr1 KO slices was no longer present. Conversely, activation of adenylate cyclase by either forskolin or Pituitary Adenylate Cyclase Activating Polypeptide (PACAP) completely reversed mGluR-LTD in WT and Fmr1 KO. 5-HT₇R activation reversed mGluR-LTD in WT and corrected exaggerated mGluR-LTD in Fmr1 KO; this effect was abolished by blockade of either adenylate cyclase or protein kinase A (PKA). Exposure of hippocampal slices to LP-211 caused an increased phosphorylation of extracellular signal regulated kinase (ERK), an intracellular effector involved in mGluR-LTD, in WT mice. Conversely, this effect was barely detectable in Fmr1 KO mice, suggesting that 5-HT₇R-mediated reversal of mGluR-LTD does not require ERK stimulation. Finally, an acute in vivo administration of LP-211 improved novel object recognition (NOR) performance in WT and Fmr1 KO mice and reduced stereotyped behavior in Fmr1 KO mice. Our results indicate that mGluR-LTD in WT and Fmr1 KO slices is bidirectionally modulated in conditions of either reduced or enhanced cAMP formation. Activation of 5-HT₇ receptors reverses mGluR-LTD by activation of the cAMP/PKA intracellular pathway. Importantly, a systemic administration of a 5-HT₇R agonist to Fmr1 KO mice corrected learning deficits and repetitive behavior. We suggest that selective 5-HT₇R agonists might become novel pharmacological tools for FXS therapy.

The genetic architecture of schizophrenia, bipolar disorder, obsessive-compulsive disorder and autism spectrum disorder

Considerable evidence suggests that autism spectrum disorders (ASD), schizophrenia (SCZ), bipolar disorder (BD) and obsessive-compulsive disorder (OCD) share a common molecular aetiology, despite their unique clinical diagnostic criteria. The aim of this study was therefore to determine and characterise the common and unique molecular architecture of ASD, SCZ, BD and OCD. Gene lists were obtained from previously published studies for ASD, BD, SCZ and for OCD. Genes identified to be common to all disorders, or unique to one specific disorder, were included for enrichment analyses using the web-server tool Enrichr. Ten genes were identified to be commonly associated with the aetiology of ASD, SCZ, BD and OCD. Enrichment analyses determined that these genes are predominantly involved in the dopaminergic and serotonergic pathways, the voltage-gated calcium ion channel gene network, folate metabolism, regulation of the hippo signaling pathway, and the regulation of gene silencing and expression. In addition to well-characterised and previously described pathways, regulation of the hippo signaling pathway was commonly associated with ASD, SCZ, BD and OCD, implicating neural development and neuronal maintenance as key in neuropsychiatric disorders. In contrast, a large number of previously associated genes were shown to be disorder-specific. And unique disorder-specific pathways and biological processes were presented for ASD, BD, SCZ and OCD aetiology. Considering the current global incidence and prevalence rates of mental health disorders, focus should be placed on cross-disorder commonalities in order to realise actionable and translatable results to combat mental health disorders.

Self-Report and Brain Indicators of Impaired Emotion Regulation in the Broad Autism Spectrum

Although not used as a diagnostic criterion, impaired emotion regulation is frequently observed in autism. The present study examined self-reported use of emotion regulation strategies in individuals scoring low or high on autistic traits. In addition, the late positive potential, which is sensitive to emotional arousal, was used to examine the effect of one strategy, reappraisal. Reporting more autistic traits was related to using more maladaptive and fewer adaptive emotion regulation strategies. Across both groups, no attenuation of the late positive potential during downregulation of unpleasant pictures was found, possibly because of the used valence-changing reappraisal operationalisation. Hence, although self-report indicated impaired emotion regulation in individuals high on autistic traits, electrophysiological findings could not confirm this.

White Matter Features Associated With Autistic Traits in Obsessive-Compulsive Disorder

Obsessive-compulsive disorder (OCD) is among the most debilitating psychiatric disorders. Comorbid autism spectrum disorder (ASD) or autistic traits may impair treatment response in OCD. To identify possible neurostructural deficits underlying autistic traits, we performed white matter tractography on diffusion tensor images (DTI) and assessed autistic trait severity using the Autism-Spectrum Quotient (AQ) in 33 OCD patients. Correlations between AQ and the DTI parameters, fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were examined in major white matter tracts that were suggested to be altered in previous OCD studies. We found a negative correlation between AQ and FA and positive correlations between AQ and MD, AD and RD in the left uncinate fasciculus using age, Beck Depression Inventory, Yale-Brown Obsessive-Compulsive Scale, intelligence quotient and medication as covariates. However, we could not detect the significant results between AQ and all DTI parameters when adding gender as a covariate. In addition, in the ASD comorbid group, FA in the left uncinate fasciculus was significantly lower than in the non-ASD comorbid group and MD and RD were significantly higher than in the non-ASD group. These results did not survive correction for multiple comparisons. In ASD, the socio-emotional dysfunction is suggested to be related to the alteration of white matter microstructure in uncinate fasciculus. Our results suggest that variations in white matter features of the left uncinate fasciculus might be partly explained by autistic traits encountered in OCD patients.

Brief Report: Cognitive Control of Social and Nonsocial Visual Attention in Autism

Prosaccade and antisaccade errors in the context of social and nonsocial stimuli were investigated in youth with autism spectrum disorder (ASD; n = 19) a matched control sample (n = 19), and a small sample of youth with obsessive compulsive disorder (n = 9). Groups did not differ in error rates in the prosaccade condition for any stimulus category. In the antisaccade condition, the ASD group demonstrated more errors than the control group for nonsocial stimuli related to circumscribed interests, but not for other nonsocial stimuli or for social stimuli. Additionally, antisaccade error rates were predictive of core ASD symptom severity. Results indicate that the cognitive control of visual attention in ASD is impaired specifically in the context of nonsocial stimuli related to circumscribed interests.

Rodent models of obsessive compulsive disorder: Evaluating validity to interpret emerging neurobiology

Obsessive Compulsive Disorder (OCD) is a common neuropsychiatric disorder with unknown molecular underpinnings. Identification of genetic and non-genetic risk factors has largely been elusive, primarily because of a lack of power. In contrast, neuroimaging has consistently implicated the cortico-striatal-thalamo-cortical circuits in OCD. Pharmacological treatment studies also show specificity, with consistent response of OCD symptoms to chronic treatment with serotonin reuptake inhibitors; although most patients are left with residual impairment. In theory, animal models could provide a bridge from the neuroimaging and pharmacology data to an understanding of pathophysiology at the cellular and molecular level. Several mouse models have been proposed using genetic, immunological, pharmacological, and optogenetic tools. These experimental model systems allow testing of hypotheses about the origins of compulsive behavior. Several models have generated behavior that appears compulsive-like, particularly excessive grooming, and some have demonstrated response to chronic serotonin reuptake inhibitors, establishing both face validity and predictive validity. Construct validity is more difficult to establish in the context of a limited understanding of OCD risk factors. Our current models may help us to dissect the circuits and molecular pathways that can elicit OCD-relevant behavior in rodents. We can hope that this growing understanding, coupled with developing technology, will prepare us when robust OCD risk factors are better understood.

Psychometric properties of the Autism-Spectrum Quotient in both clinical and non-clinical samples: Chinese version for mainland China

BACKGROUND

The Autism-Spectrum Quotient (AQ) is widely used to quantify autistic traits, which have been evaluated in the parents of individuals with autism spectrum disorders (ASD) and in the general population. This paper's objective was to investigate the AQ's psychometric properties of the Chinese version for mainland China and to establish whether the pattern of sex differences in the quantity of autistic traits exists. We also examined the usefulness of the AQ in differentiating between individuals with ASD, schizophrenia (SCH), obsessive-compulsive disorder (OCD) and healthy controls (HC).

METHODS

In this study, the psychometric properties of the AQ were assessed in 1037 parents of children with ASD and in 1040 parents of typically developing children (TDC). Additionally, 32 participants with ASD, 37 patients with SCH, 38 OCD patients and 38 healthy controls (matched for age, gender and IQ) were assessed with the AQ.

RESULTS

The internal consistency and test-retest reliability of the AQ and AQ subscales were within an acceptable range. Parents of ASD children scored higher than TDC parents on total AQ and AQ subscales, and TDC parents scored more than parents of ASD children on 2 items of 50. Fathers scored higher than did mothers on total AQ and four subscales, with the sole exception being the subscale attention to detail. The total AQ score of the ASD group was higher than that of the SCH, OCD and HC groups, and the total AQ score of the HC group was significantly lower than that of the SCH and OCD groups, with no differences being observed between the SCH and OCD groups.

CONCLUSIONS

The Mandarin AQ demonstrated promising psychometric properties and was a reliable instrument for quantifying autistic traits in both clinical and non-clinical samples in mainland China.

Subclinical autism spectrum symptoms in pediatric obsessive-compulsive disorder

The literature on subclinical autism spectrum (ASD) symptoms in pediatric obsessive-compulsive disorder (OCD) is scarce, and it remains unclear whether ASD symptoms are related to OCD severity. The aims of the present study were to assess the prevalence of ASD symptoms and age and sex differences in children and adolescents with OCD, and to explore the relation between ASD symptoms and OCD severity. This is the largest study of ASD symptoms in an OCD population to date, and the first directly aimed at elucidating sex and age differences in this matter. The study used baseline data from the Nordic Long-term OCD Treatment Study in which parents of 257 children and adolescents with OCD aged 7-17 completed the Autism Spectrum Screening Questionnaire. OCD severity was assessed with the Children's Yale-Brown Obsessive Compulsive Scale. Pediatric OCD patients were found to exhibit elevated rates of ASD symptoms compared to a norm group of school-age children. ASD symptoms were concentrated in a subgroup with a prevalence of 10-17 %. This subgroup was characterized by a male preponderance with a sex ratio of approximately 2.6:1, while children versus adolescents with OCD exhibited similar rates. Autism-specific social and communication difficulties were not related to OCD severity, while restricted repetitive behavior was positively related to OCD severity. The results indicate that clinicians need to be aware of ASD symptoms in children and adolescents with OCD since one out of ten exhibits such symptoms at a clinical sub-threshold.

The Toronto Obsessive-Compulsive Scale: Psychometrics of a Dimensional Measure of Obsessive-Compulsive Traits

OBJECTIVE

To describe the Toronto Obsessive-Compulsive Scale (TOCS), a novel 21-item parent- or self-report questionnaire that covers wide variation in obsessive-compulsive (OC) traits, and to evaluate its psychometric properties in a community-based pediatric sample.

METHOD

The TOCS was completed for 16,718 children and adolescents between the ages of 6 and 17 years in a community setting. Internal consistency, convergent validity with the Obsessive-Compulsive Scale of the Child Behaviour Checklist (CBCL-OCS), divergent validity with the Strengths and Weaknesses of ADHD (Attention-Deficit/Hyperactivity Disorder) Symptoms and Normal Behaviour Rating Scale (SWAN), interrater reliability, as well as sensitivity and specificity of the TOCS were assessed.

RESULTS

The internal consistency of the 21 TOCS items was excellent (Cronbach's α = 0.94). TOCS was moderately correlated with the CBCL-OCS (Spearman correlation = 0.51) and poorly correlated with the SWAN (Pearson correlation = 0.02). Sensitivity and specificity analyses indicated that a TOCS total score of greater than 0 successfully discriminated community-reported obsessive-compulsive disorder (OCD) cases from noncases. OC traits were continuously distributed both at the total score and dimensional level in our pediatric community sample.

CONCLUSION

TOCS is a multidimensional measure of OC traits in children and adolescents with sound psychometric properties. TOCS reveals that OC traits are common and continuously distributed in a community sample. TOCS may be a useful measure for studies of the characteristics and etiology of OC traits.

Prevalence of Autism Spectrum Disorders in Ecuador: A Pilot Study in Quito

This research presents the results of the first phase of the study on the prevalence of pupils with Autism Spectrum Disorder (ASD) in regular education in Quito, Ecuador. One-hundred-and-sixty-one regular schools in Quito were selected with a total of 51,453 pupils. Prevalence of ASD was assessed by an interview with the rector of the school or its delegate. Results show an extremely low prevalence of 0.11 % of pupils with any ASD diagnosis; another 0.21 % were suspected to have ASD, but were without a diagnosis. This low prevalence suggests that children and adolescents with ASD are not included in regular education in Quito. These results are discussed in the light of low diagnostic identification of ASD and low inclusion tolerance.

Identifying the lost generation of adults with autism spectrum conditions

Autism spectrum conditions comprise a set of early-onset neurodevelopmental syndromes with a prevalence of 1% across all ages. First diagnosis in adulthood has finally become recognised as an important clinical issue due to the increasing awareness of autism, broadening of diagnostic criteria, and the introduction of the spectrum concept. Thus, the idea of a lost generation of people who were previously excluded from a diagnosis of classic autism has arisen. Making a first diagnosis of autism spectrum conditions in adults can be challenging for practical reasons (eg, no person to provide a developmental history), developmental reasons (eg, the acquisition of learnt or camouflaging strategies), and clinical reasons (eg, high frequency of co-occurring disorders). The diagnostic process includes referral, screening, interviews with informants and patients, and functional assessments. In delineating differential diagnoses, true comorbidities, and overlapping behaviour with other psychiatric diagnoses, particular attention should be paid to anxiety, depression, obsessive-compulsive disorder, psychosis, personality disorders, and other neurodevelopmental disorders. Possible misdiagnosis, especially in women, should be explored. The creation of supportive, accepting, and autism-friendly social and physical environments is important and requires a coordinated effort across agencies and needs support from government policies.

Genetic and environmental influences underlying the relationship between autistic traits and temperament and character dimensions in adulthood

BACKGROUND

In recent years, several twin studies adopted a dimensional approach to Autism Spectrum Disorders (ASD) and estimated the contribution of genetic and environmental influences to variation in autistic traits. However, no study was performed on adults over 18 years of age and all but two studies were based on parent or teacher ratings. Also, the genetic and environmental contributions to the interplay between autistic traits and adult personality dimensions have not been investigated.

METHODS

A sample of 266 complete twin pairs (30% males, mean age 40 ± 12 years) drawn from the population-based Italian Twin Register was administered the Autism-Spectrum Quotient, Temperament and Character Inventory (TCI-125), and General Health Questionnaire (GHQ-12). Genetic structural equation modelling was performed with the Mx program. Estimates were adjusted for gender, age, and GHQ-12 score.

RESULTS

Genetic factors accounted for 44% and 20%-49% of individual differences in autistic traits and TCI dimensions, respectively. Unshared environmental factors explained the remaining proportion of variance. Consistently with the notion of a personality profile in ASD characterised by obsessive temperament, autistic traits showed significant phenotypic correlations with several TCI dimensions (positive: HA; negative: NS, RD, SD, C). Genetic and unshared environmental correlations between AQ and these TCI dimensions were significant. The degree of genetic overlap was generally greater than the degree of environmental overlap.

CONCLUSIONS

Despite some limitations, this study suggests that genetic factors contribute substantially to individual differences in autistic traits in adults, with unshared environmental influences also playing an important role. It also suggests that autistic traits and the majority of temperament and character dimensions share common genetic and environmental aetiological factors.

Exploring anxiety symptoms in a large-scale twin study of children with autism spectrum disorders, their co-twins and controls

BACKGROUND

Although many children with autism spectrum disorders (ASDs) experience difficulties with anxiety,the manifestation of these difficulties remains unresolved. The current study assessed anxiety in a large population based twin sample, aged 10–15 years. Phenotypic analyses were used to explore anxiety symptoms in children with ASDs, their unaffected co-twins and a control sample.

METHODS

Participants included 146 families from the Twins Early Development Study (TEDS) where one or both children had a suspected ASD. Eighty control families were also included. The Revised Child Anxiety and Depression scale (Chorpita, Yim, Moffitt, Umemoto & Francis, 2000) was completed (self- and parent-report), along with diagnostic and cognitive tests. Children were categorized into four groups (a) ASD (b) Broader Autism Phenotype (BAP: mainly co-twins of children with ASDs, with high subclinical autistic traits) (c) unaffected co-twins (with neither ASDs nor BAP) (d) controls.

RESULTS

Children in the ASD and BAP groups scored significantly higher than controls for all parent-rated (although not child-rated) anxiety subscales.There were no significant differences between the ASD and BAP groups for any of the parent-rated anxiety subscales. Compared with controls, unaffected co-twins showed significantly heightened Social Anxiety, Generalized Anxiety,and Panic symptoms. Significant associations were observed between certain anxiety subscales and both IQ and ASD symptoms. For example, greater parent-rated Social Anxiety was associated with higher IQ and increased social and communicative impairments. Significant interrater correlations were observed for anxiety reports in children with ASDs (r = .27–.54; p < .01), their unaffected co-twins (r = .32–.63; p < .01) and controls (r = .23–.43; p < .01)suggesting that children in this sample with and without ASD symptoms were able to report on their anxiety symptoms with some accuracy.

CONCLUSIONS

These findings support previous reports of heightened anxiety in children with ASDs, at least on parent-reported measures. Unaffected co-twins of children with ASDs also showed increased anxiety, generating questions about the potential etiological overlap between ASDs and anxiety. Progress in this area now depends on more refined anxiety measurement in ASDs and continued investigation of interrater differences.

Reduced behavioral flexibility in autism spectrum disorders

OBJECTIVE

Restricted and repetitive behaviors, and a pronounced preference for behavioral and environmental consistency, are distinctive characteristics of autism spectrum disorders (ASD). Whether these clinical features of ASD are related to fundamental neuropsychological impairments in behavioral flexibility remains to be clarified.

METHOD

Forty-one individuals with ASD and 37 matched controls performed a probabilistic reversal learning task to assess behavioral flexibility. Participants learned to choose the correct stimulus location from a pair of locations to win points (acquisition). After making the correct choice over multiple trials, the rewarded stimulus location changed without warning (reversal). Feedback was provided on an 80:20 probabilistic schedule, with 80% of correct choices and 20% of incorrect choices randomly reinforced.

RESULTS

ASD and control participants performed comparably during acquisition. At reversal, ASD participants initially chose the new correct location as quickly as controls, but then more frequently reverted back to the previously preferred response. The ASD group also more frequently shifted back to the previous response choice immediately following intermittent non-reinforcement of the new correct response. The number of regressive errors was positively correlated with independently ascertained clinical ratings of restricted and repetitive behaviors, but not other core features of ASD.

CONCLUSIONS

Restricted and repetitive behaviors in ASD are associated with neurocognitive deficits in flexible choice behavior. Preclinical research has established that frontostriatal circuitry supports flexibility on reversal learning tasks. Thus, alterations in this circuitry may contribute to behavioral rigidity in ASD and represent a target for therapeutic intervention.

The effect of DSM-5 criteria on externalizing, internalizing, behavioral and adaptive symptoms in children diagnosed with autism

OBJECTIVE

Diagnostic criteria for autism spectrum disorders (ASDs) are changing with the fifth edition of the Diagnostic and Statistical Manual (DSM-5), which simplifies the diagnostic categories into social/emotional deficits and repetitive and restricted behavior. ASDs have been closely linked to a variety of other disorders, in particular externalizing disorders such as ADHD, and internalizing disorders including anxiety disorders and obsessive compulsive disorder. The present study examines the externalizing, internalizing, behavioral and adaptive symptoms of children with ASD.

METHOD

Children diagnosed with the DSM-IV who do not meet diagnostic criteria for DSM-5 and were compared to a non-ASD sample and a sample of those who meet the new criteria. Differences were examined between the three experimental groups with respect to internalizing, externalizing, behavioral severity and adaptive behavior.

RESULTS

No significant differences were observed between the DSM-5 and DSM-IV groups with respect to composite and subscale scores on the externalizing, behavior severity index and adaptive behavior domains of the Behavior Assessment System for Children, Second Edition.

CONCLUSIONS

Significantly more impairment was evident for both ASD groups compared to the no-ASD group.

Surface anatomical profile of the cerebral cortex in obsessive-compulsive disorder: a study of cortical thickness, folding and surface area

BACKGROUND

Studying the distribution of anatomical abnormalities over the entire cortical surface can help to identify key neural circuits implicated in generating symptoms of neuropsychiatric disorders. There is a significant inconsistency among studies investigating the neuroanatomy of obsessive-compulsive disorder (OCD) because of the confounding influence of co-morbid depression and medication use and the lack of unbiased estimation of whole-brain morphometric changes. It is also unknown whether the distinct surface anatomical properties of thickness, surface area and gyrification, which collectively contribute to grey matter volume (GMV), are independently affected in OCD. Method The cortical maps of thickness, gyrification and surface areal change were acquired from 23 unmedicated OCD patients and 20 healthy controls using an unbiased whole-brain surface-based morphometric (SBM) method to detect regional changes in OCD. Subcortical structures were not assessed in this study.

RESULTS

Patients showed a significant increase in the right inferior parietal cortical thickness. Significant increases in gyrification were also noted in the left insula, left middle frontal and left lateral occipital regions extending to the precuneus and right supramarginal gyrus in OCD. Areal contraction/expansion maps revealed no significant regional differences between the patients and controls. In patients, gyrification of the insula significantly predicted the symptom severity measured using Yale-Brown Obsessive-Compulsive Scale (YBOCS).

CONCLUSIONS

An alteration in the cortical surface anatomy is an important feature of OCD seen in unmedicated samples that relates to the severity of the illness. The results underscore the presence of a neurodevelopmental aberration underlying the pathophysiology of OCD.

Glutamate system genes and brain volume alterations in pediatric obsessive-compulsive disorder: a preliminary study

Obsessive-compulsive disorder (OCD) has been associated with regional volumetric brain abnormalities, which provide promising intermediate phenotypes of the disorder. In this study, volumes of brain regions selected for a priori evidence of association with OCD (orbitofrontal cortex (OFC), anterior cingulate cortex (ACC), thalamus, caudate, putamen, globus pallidus and pituitary) were measured using structural magnetic resonance imaging (MRI) in 20 psychotropic-naïve pediatric OCD patients. We examined the association between these regional brain volumes and a total of 519 single nucleotide polymorphisms (SNPs) from nine glutamatergic candidate genes (DLGAP1, DLGAP2, DLGAP3, GRIN2B, SLC1A1, GRIK2, GRIK3, SLITRK1 and SLITRK5). These genes were selected based on either previous reported association with OCD in humans or evidence from animal models of OCD. After correcting for multiple comparisons by permutation testing, no SNP remained significantly associated with volumetric changes. The strongest trend toward association was identified between two SNPs in DLGAP2 (rs6558484 and rs7014992) and OFC white matter volume. Our other top ranked association findings were with ACC, OFC and thalamus. These preliminary results suggest that sequence variants in glutamate candidate genes may be associated with structural neuroimaging phenotypes of OCD.

Detecting autism spectrum disorders in the general practitioner's practice

It takes considerable time before Autism Spectrum Disorders are diagnosed. Validated diagnostic instruments are available, but not applicable to primary healthcare. By means of a case–control study we investigated whether there were differences in presented complaints and referral patterns between children with ASD (n = 49) and a control group of children without ASD (n = 81). Children with ASD were often presented as crybabies and often showed feeding problems. They visited the GP’s surgery more often with anxiety disorders, enuresis, and sleeping disorders. They were referred more often to physiotherapists and speech-therapists and had tympanostomy tubes and tonsillectomies more often. Depression in the parents of children with ASD was remarkably prevalent.

Common and distinct neural features of social and non-social reward processing in autism and social anxiety disorder

Autism spectrum disorders (ASDs) and social anxiety disorder (SAD) are both characterized by social dysfunction, but no study to date has compared neural responses to social rewards in ASDs and SAD. Neural responses during social and non-social reward anticipation and outcomes were examined in individuals with ASD (n = 16), SAD (n = 15) and a control group (n = 19) via functional magnetic resonance imaging. Analyses modeling all three groups revealed increased nucleus accumbens (NAc) activation in SAD relative to ASD during monetary reward anticipation, whereas both the SAD and ASD group demonstrated decreased bilateral NAc activation relative to the control group during social reward anticipation. During reward outcomes, the SAD group did not differ significantly from the other two groups in ventromedial prefrontal cortex activation to either reward type. Analyses comparing only the ASD and SAD groups revealed greater bilateral amygdala activation to social rewards in SAD relative to ASD during both anticipation and outcome phases, and the magnitude of left amygdala hyperactivation in the SAD group during social reward anticipation was significantly correlated with the severity of trait anxiety symptoms. Results suggest reward network dysfunction to both monetary and social rewards in SAD and ASD during reward anticipation and outcomes, but that NAc hypoactivation during monetary reward anticipation differentiates ASD from SAD.

Mice genetically depleted of brain serotonin display social impairments, communication deficits and repetitive behaviors: possible relevance to autism

Autism is a complex neurodevelopmental disorder characterized by impaired reciprocal social interaction, communication deficits and repetitive behaviors. A very large number of genes have been linked to autism, many of which encode proteins involved in the development and function of synaptic circuitry. However, the manner in which these mutated genes might participate, either individually or together, to cause autism is not understood. One factor known to exert extremely broad influence on brain development and network formation, and which has been linked to autism, is the neurotransmitter serotonin. Unfortunately, very little is known about how alterations in serotonin neuronal function might contribute to autism. To test the hypothesis that serotonin dysfunction can contribute to the core symptoms of autism, we analyzed mice lacking brain serotonin (via a null mutation in the gene for tryptophan hydroxylase 2 (TPH2)) for behaviors that are relevant to this disorder. Mice lacking brain serotonin (TPH2-/-) showed substantial deficits in numerous validated tests of social interaction and communication. These mice also display highly repetitive and compulsive behaviors. Newborn TPH2-/- mutant mice show delays in the expression of key developmental milestones and their diminished preference for maternal scents over the scent of an unrelated female is a forerunner of more severe socialization deficits that emerge in weanlings and persist into adulthood. Taken together, these results indicate that a hypo-serotonin condition can lead to behavioral traits that are highly characteristic of autism. Our findings should stimulate new studies that focus on determining how brain hyposerotonemia during critical neurodevelopmental periods can alter the maturation of synaptic circuits known to be mis-wired in autism and how prevention of such deficits might prevent this disorder.

A prospective Cross-sectional Cohort Assessment of Health, Physical, and Behavioral Problems in Autism Spectrum Disorders

OBJECTIVES

Autism spectrum disorder (ASD) is diagnostically defined by impaired socialization/communication and stereotypical behaviors. Health, physical, and behavioral problems have also been described in subjects diagnosed with an ASD, but have usually been examined in isolation. The purpose of the present study was to for the first time, systematically and quantitatively, examines health, physical and behavioral problems in a cohort of subjects diagnosed with an ASD.

MATERIALS AND METHODS

A prospective cross-sectional ASD cohort (n=54) was evaluated for health, physical, and behavioral symptoms derived from parentally completed Autism Treatment Evaluation Checklist (ATEC) forms. The study protocol received Institutional Review Board (IRB) approval from Liberty IRB, Inc (Deland, FL).

OUTCOMES

The results showed the following occurrence of symptoms among study participants: gastrointestinal disturbances=48%, incontinence=57%, sleep problems=57%, eating disorders=94%, hyperactivity=67%, lethargy=26%, sensory processing problems=85%, anxiety/fear=74%, behavioral problems=89%, and obsessive-compulsive behaviors=92%. Of all of the areas examined, eating problems, behavioral problems, and obsessive-compulsive behaviors, were reported by the parents to be the most serious and problematic.

CONCLUSIONS

The present findings, taken together with previous research, suggest that subjects diagnosed with an ASD have significant health, physical, and behavioral problems beyond the symptoms evaluated in the diagnostic criteria used to diagnosis an ASD. The present findings also suggest the ATEC provides an economical means for healthcare providers to identify health, physical, and behavioral problems in subjects diagnosed with an ASD.

Reward circuitry dysfunction in psychiatric and neurodevelopmental disorders and genetic syndromes: animal models and clinical findings

This review summarizes evidence of dysregulated reward circuitry function in a range of neurodevelopmental and psychiatric disorders and genetic syndromes. First, the contribution of identifying a core mechanistic process across disparate disorders to disease classification is discussed, followed by a review of the neurobiology of reward circuitry. We next consider preclinical animal models and clinical evidence of reward-pathway dysfunction in a range of disorders, including psychiatric disorders (i.e., substance-use disorders, affective disorders, eating disorders, and obsessive compulsive disorders), neurodevelopmental disorders (i.e., schizophrenia, attention-deficit/hyperactivity disorder, autism spectrum disorders, Tourette's syndrome, conduct disorder/oppositional defiant disorder), and genetic syndromes (i.e., Fragile X syndrome, Prader-Willi syndrome, Williams syndrome, Angelman syndrome, and Rett syndrome). We also provide brief overviews of effective psychopharmacologic agents that have an effect on the dopamine system in these disorders. This review concludes with methodological considerations for future research designed to more clearly probe reward-circuitry dysfunction, with the ultimate goal of improved intervention strategies.

Adults with autism spectrum disorders exhibit decreased sensitivity to reward parameters when making effort-based decisions

BACKGROUND

Efficient effort expenditure to obtain rewards is critical for optimal goal-directed behavior and learning. Clinical observation suggests that individuals with autism spectrum disorders (ASD) may show dysregulated reward-based effort expenditure, but no behavioral study to date has assessed effort-based decision-making in ASD.

METHODS

The current study compared a group of adults with ASD to a group of typically developing adults on the Effort Expenditure for Rewards Task (EEfRT), a behavioral measure of effort-based decision-making. In this task, participants were provided with the probability of receiving a monetary reward on a particular trial and asked to choose between either an "easy task" (less motoric effort) for a small, stable reward or a "hard task" (greater motoric effort) for a variable but consistently larger reward.

RESULTS

Participants with ASD chose the hard task more frequently than did the control group, yet were less influenced by differences in reward value and probability than the control group. Additionally, effort-based decision-making was related to repetitive behavior symptoms across both groups.

CONCLUSIONS

These results suggest that individuals with ASD may be more willing to expend effort to obtain a monetary reward regardless of the reward contingencies. More broadly, results suggest that behavioral choices may be less influenced by information about reward contingencies in individuals with ASD. This atypical pattern of effort-based decision-making may be relevant for understanding the heightened reward motivation for circumscribed interests in ASD.

Pharmacologic treatment of repetitive behaviors in autism spectrum disorders: evidence of publication bias

OBJECTIVE

The goal of this study was to examine the efficacy of serotonin receptor inhibitors (SRIs) for the treatment of repetitive behaviors in autism spectrum disorders (ASD).

METHODS

Two reviewers searched PubMed and Clinicaltrials.gov for randomized, double-blind, placebo-controlled trials evaluating the efficacy of SRIs for repetitive behaviors in ASD. Our primary outcome was mean improvement in ratings scales of repetitive behavior. Publication bias was assessed by using a funnel plot, the Egger's test, and a meta-regression of sample size and effect size.

RESULTS

Our search identified 5 published and 5 unpublished but completed trials eligible for meta-analysis. Meta-analysis of 5 published and 1 unpublished trial (which provided data) demonstrated a small but significant effect of SRI for the treatment of repetitive behaviors in ASD (standardized mean difference: 0.22 [95% confidence interval: 0.07-0.37], z score = 2.87, P < .005). There was significant evidence of publication bias in all analyses. When Duval and Tweedie's trim and fill method was used to adjust for the effect of publication bias, there was no longer a significant benefit of SRI for the treatment of repetitive behaviors in ASD (standardized mean difference: 0.12 [95% confidence interval: -0.02 to 0.27]). Secondary analyses demonstrated no significant effect of type of medication, patient age, method of analysis, trial design, or trial duration on reported SRI efficacy.

CONCLUSIONS

Meta-analysis of the published literature suggests a small but significant effect of SRI in the treatment of repetitive behaviors in ASD. This effect may be attributable to selective publication of trial results. Without timely, transparent, and complete disclosure of trial results, it remains difficult to determine the efficacy of available medications.

Networking in autism: leveraging genetic, biomarker and model system findings in the search for new treatments

Autism Spectrum Disorder (ASD) is a common neurodevelopmental disorder affecting approximately 1% of children. ASD is defined by core symptoms in two domains: negative symptoms of impairment in social and communication function, and positive symptoms of restricted and repetitive behaviors. Available treatments are inadequate for treating both core symptoms and associated conditions. Twin studies indicate that ASD susceptibility has a large heritable component. Genetic studies have identified promising leads, with converging insights emerging from single-gene disorders that bear ASD features, with particular interest in mammalian target of rapamycin (mTOR)-linked synaptic plasticity mechanisms. Mouse models of these disorders are revealing not only opportunities to model behavioral perturbations across species, but also evidence of postnatal rescue of brain and behavioral phenotypes. An intense search for ASD biomarkers has consistently pointed to elevated platelet serotonin (5-HT) levels and a surge in brain growth in the first 2 years of life. Following a review of the diversity of ASD phenotypes and its genetic origins and biomarkers, we discuss opportunities for translation of these findings into novel ASD treatments, focusing on mTor- and 5-HT-signaling pathways, and their possible intersection. Paralleling the progress made in understanding the root causes of rare genetic syndromes that affect cognitive development, we anticipate progress in models systems using bona fide ASD-associated molecular changes that have the potential to accelerate the development of ASD diagnostics and therapeutics.

Predictive validity of a non-induced mouse model of compulsive-like behavior

A key to advancing the understanding of obsessive-compulsive disorder (OCD)-like symptoms is the development of spontaneous animal models. Over 55 generations of bidirectional selection for nest-building behavior in house mice, Mus musculus, resulted in a 40-fold difference in the amount of cotton used for a nest in high (BIG) and low (SMALL) selected lines. The nesting behavior of BIG mice appears to be compulsive-like and has initial face validity as an animal model for OCD in humans. Compulsive-like digging behavior was assessed; BIG male mice buried about three times as many marbles as SMALL male mice, strengthening face validity. Using the open field and elevated plus maze, SMALL male mice showed higher levels of anxiety/fear-like behavior than BIG male mice, indicating that compulsive-like and not anxiety-like behavior was measured. To establish predictive validity, chronic (4 weeks) oral administration of fluoxetine (30, 50 and 100mg/kg/day) and clomipramine (80 mg/kg/day), both effective in treating OCD, significantly reduced compulsive-like nest-building behavior in BIG male mice. Compulsive-like digging behavior was also significantly reduced by chronic oral fluoxetine (30 and 80 mg/kg/day) treatment in BIG male mice. General locomotor activity was not affected by chronic oral fluoxetine (30 and 80 mg/kg/day) treatment; chronic oral treatment with desipramine (30 mg/kg/day), an antidepressant not effective in treating OCD, had no effect on nesting behavior of BIG male mice, strengthening predictive validity. Together, the results indicate that these mice have good face and predictive validity as a non-induced mouse model of compulsive-like behavior relevant to OCD.

Basal ganglia shapes predict social, communication, and motor dysfunctions in boys with autism spectrum disorder

OBJECTIVE

Basal ganglia abnormalities have been suggested as contributing to motor, social, and communicative impairments in autism spectrum disorder (ASD). Volumetric analyses offer limited ability to detect localized differences in basal ganglia structure. Our objective was to investigate basal ganglia shape abnormalities and their association with behavioral features of ASD, which may involve multiple frontal-subcortical circuits.

METHOD

Basal ganglia were manually delineated from MR images of 32 boys with ASD and 45 typically developing (TD) boys. Large deformation diffeomorphic metric mapping (LDDMM) was used to assess between-group differences in basal ganglia shape and to examine associations with motor, praxis, and reciprocal social and communicative impairments in ASD.

RESULTS

Boys with ASD showed changes in right basal ganglia shape as compared with TD boys; surface deformation was present in the caudate, putamen, and globus pallidus but did not stand up to correction for multiple comparisons. Brain-behavior correlation findings were more robust; analyses accounting for multiple comparisons revealed, in boys with ASD, surface inward deformation of the right posterior putamen predicted poorer motor skill, whereas surface inward deformation of the bilateral anterior and posterior putamen predicted poorer praxis. Surface outward deformation in the bilateral medial caudate head predicted greater reciprocal social and communicative impairment.

CONCLUSIONS

Motor, social, and communicative impairments in boys with ASD are associated with shape abnormalities in the basal ganglia. The findings suggest abnormalities within parallel frontal-subcortical circuits are differentially associated with impaired acquisition of motor and reciprocal social and communicative skills in ASD.