Impaired response inhibition in autism spectrum disorders, a marker of vulnerability to schizophrenia spectrum disorders?

Autism spectrum disorder and schizophrenia: An updated conceptual review

Autism spectrum disorder (ASD) and schizophrenia (SCZ) are separate disorders, with distinct clinical profiles and natural histories. ASD, typically diagnosed in childhood, is characterized by restricted or repetitive interests or behaviors and impaired social communication, and it tends to have a stable course. SCZ, typically diagnosed in adolescence or adulthood, is characterized by hallucinations and delusions, and tends to be associated with declining function. However, youth with ASD are three to six times more likely to develop SCZ than their neurotypical counterparts, and increasingly, research has shown that ASD and SCZ converge at several levels. We conducted a systematic review of studies since 2013 relevant to understanding this convergence, and present here a narrative synthesis of key findings, which we have organized into four broad categories: symptoms and behavior, perception and cognition, biomarkers, and genetic and environmental risk. We then discuss opportunities for future research into the phenomenology and neurobiology of overlap between ASD and SCZ. Understanding this overlap will allow for researchers, and eventually clinicians, to understand the factors that may make a child with ASD vulnerable to developing SCZ. LAY SUMMARY: Autism spectrum disorder and schizophrenia are distinct diagnoses, but people with autism and people with schizophrena share several characteristics. We review recent studies that have examined these areas of overlap, and discuss the kinds of studies we will need to better understand how these disorders are related. Understanding this will be important to help us identify which autistic children are at risk of developing schizophrenia.

The Monash Autism-ADHD genetics and neurodevelopment (MAGNET) project design and methodologies: a dimensional approach to understanding neurobiological and genetic aetiology

Background

ASD and ADHD are prevalent neurodevelopmental disorders that frequently co-occur and have strong evidence for a degree of shared genetic aetiology. Behavioural and neurocognitive heterogeneity in ASD and ADHD has hampered attempts to map the underlying genetics and neurobiology, predict intervention response, and improve diagnostic accuracy. Moving away from categorical conceptualisations of psychopathology to a dimensional approach is anticipated to facilitate discovery of data-driven clusters and enhance our understanding of the neurobiological and genetic aetiology of these conditions. The Monash Autism-ADHD genetics and neurodevelopment (MAGNET) project is one of the first large-scale, family-based studies to take a truly transdiagnostic approach to ASD and ADHD. Using a comprehensive phenotyping protocol capturing dimensional traits central to ASD and ADHD, the MAGNET project aims to identify data-driven clusters across ADHD-ASD spectra using deep phenotyping of symptoms and behaviours; investigate the degree of familiality for different dimensional ASD-ADHD phenotypes and clusters; and map the neurocognitive, brain imaging, and genetic correlates of these data-driven symptom-based clusters.

Methods

The MAGNET project will recruit 1,200 families with children who are either typically developing, or who display elevated ASD, ADHD, or ASD-ADHD traits, in addition to affected and unaffected biological siblings of probands, and parents. All children will be comprehensively phenotyped for behavioural symptoms, comorbidities, neurocognitive and neuroimaging traits and genetics.

Conclusion

The MAGNET project will be the first large-scale family study to take a transdiagnostic approach to ASD-ADHD, utilising deep phenotyping across behavioural, neurocognitive, brain imaging and genetic measures.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13229-021-00457-3.

The interaction between positive schizotypy and high sensitivity C-reactive protein on response inhibition in female individuals

This study aimed to measure the associations between high sensitivity C-reactive protein (hsCRP), childhood maltreatment (CM), schizotypy and response inhibition, and to explore the interactions between hsCRP, CM and schizotypy on response inhibition. Two hundred and fourteen participants completed the Stop-Signal Task (SST), the Schizotypy Personality Questionnaire (SPQ) and the Childhood Trauma Questionnaire-Short Form (CTQ), which measured response inhibition, schizotypy and history of CM respectively. The level of hsCRP was also measured. The high schizotypy group (n = 114) had higher scores on SPQ and CTQ, higher hsCRP levels and longer SST reaction times (SSRTs) than the low schizotypy group (n = 100). In female participants, SSRT had a positive correlation with the SPQ positive factor and the disorganized SPQ factor and a positive correlation with physical neglect. HsCRP was positively correlated with the SPQ negative factor and positive SPQ factor. In male participants, SSRT was negatively correlated with emotional neglect and physical neglect. The majority of correlations between CTQ and SPQ variables were significant in both female and male participants. In female participants, hsCRP significantly predicted SSRT, and hsCRP significantly interacted with positive schizotypy in predicting SSRT.

Non-diagnostic symptoms in a mouse model of autism in relation to neuroanatomy: the BTBR strain reinvestigated

Several mouse models of autism spectrum disorder (ASD), including the BTBR T + tf/J (BTBR) inbred strain, display a diverse array of behavioral deficits with particular face validity. Here we propose that phenotyping these preclinical models of ASD should avoid excessive reliance on appearance validity of the behavioral observations. BTBR mice were examined in three non-diagnostic symptoms modalities, beside an anatomical investigation for construct validity. The BTBR strain displayed poor sensorimotor integration as reflected by shorter stride length and greater latency on the balance beam task (BBT) when compared with C57BL/6 (B6) controls. Also, locomotor indices in the open-field task (OFT) revealed that BTBR mice traveled longer distances with a remarkably faster exploration than the B6 group in favor of hyperactivity and impulsiveness. Furthermore, analysis of spatial performance including search strategies in the Morris water task (MWT) indicated spatial impairment in the BTBR strain due to failure to employ spatial strategies during navigation. Quantitative cytoarchitectonics and volumetric examinations also indicated abnormal cortical and subcortical morphology in the BTBR mice. The results are discussed in relation to the neuroanatomical correlates of motor and cognitive impairments in the BTBR strain. We conclude that non-diagnostic autistic-like symptoms in the BTBR mouse strain can be impacted by autism risk factors in a similar way than the traditional diagnostic signs.

The association between pre-pregnancy overweight/obesity and offspring's behavioral problems and executive functioning

The prevalence of obesity among women of childbearing age has been rising dramatically over the last decades. Pre-pregnancy obesity may have negative neurodevelopmental consequences for the offspring. The present study examined the association of maternal pre-pregnancy overweight and obesity with child behavior problems and executive functioning at age 5 years. Data of 4094 mother-child pairs of the Amsterdam Born Children and their Development birth cohort study was used. Child behavioral problems were assessed with the maternal and teacher version of the Strengths and Difficulties Questionnaire. Two executive functioning constructs, inhibitory control and cognitive flexibility, were measured with the Response Organization Objects task of the Amsterdam Neuropsychological Tasks test battery. Increased maternal pre-pregnancy BMI was associated with an increase in children's behavioral problems (OR total behavioral problems reported by mothers pre-pregnancy obesity versus normal weight: 1.78 [95% CI 1.17 to 2.69] and reported by teachers for pre-pregnancy overweight versus normal weight: 1.32 [1.00 to 1.74]). Maternal pre-pregnancy obesity was associated with an increase in peer relationship problems reported by teachers (OR: 1.77 [1.18 to 2.64]). It was also associated with a small decrease in cognitive flexibility (increased Reaction Time in ms: B = 67.59 [5.88 to 129.30] and Within Subject Standard Deviation in ms: B = 76.46 [32.00 to 120.92]), but not with inhibitory control. Cognitive flexibility did not mediate the association between maternal pre-pregnancy BMI and children's behavioral problems.

Neuropsychological Consequences for Survivors of Childhood Brain Tumor in Malaysia

Objective: This study aimed to evaluate neuropsychological consequences in survivors of childhood brain tumor.

Method: A case-control study was conducted over a period of 4 months in a tertiary referral center in Kuala Lumpur, Malaysia. Fourteen survivors of childhood brain tumor aged 7–18 years, who were off-treatment for at least 1 year and were in remission, and 31 unrelated healthy controls were recruited. The median age at diagnosis was 8.20 years (range: 0.92–12.96 years). The diagnoses of brain tumors were medulloblastoma, germ cell tumor, pineocytoma, pilocystic astrocytoma, suprasellar germinoma, and ependymoma. Eleven survivors received central nervous system irradiation. Seven tasks were selected from the Amsterdam Neuropsychological Tasks program to evaluate alertness (processing speed), and major aspects of executive functioning, such as working memory capacity, inhibition, cognitive flexibility, and sustained attention. Speed, stability and accuracy of responses were the main outcome measures.

Results: Survivors of childhood brain tumor showed statistically significant poorer performance on all tasks compared to healthy controls. Both processing speed and accuracy were impaired in the survivors, in particular under more complex task conditions. The survivors demonstrated deficits in alertness, sustained attention, working memory capacity, executive visuomotor control, and cognitive flexibility. Longer duration off treatment appeared to be correlated with poorer alertness, memory capacity, and inhibition.

Conclusion: Survivors of childhood brain tumor in our center showed impaired neuropsychological functioning. Development of less toxic treatment protocols is important to prevent late effects of cognitive deficits in survivors of childhood brain tumor.

Differences in frontotemporal dysfunction during social and non-social cognition tasks between patients with autism spectrum disorder and schizophrenia

Although literature evidence suggests deficits in social and non-social cognition in patients with autistic spectrum disorder (ASD) and schizophrenia (SCZ), the difference in neural correlates of the impairments between the two disorders has not been elucidated. We examined brain function in response to a non-social cognition and a social cognition task using functional near-infrared spectroscopy (fNIRS) in 13 patients with ASD, 15 patients with SCZ, and 18 healthy subjects. We assessed the brain function of participants using a verbal fluency task and an emotional facial recognition task. The patients with ASD showed significantly reduced brain activation in the left frontotemporal area during both tasks compared to healthy subjects. The patients with ASD with larger score in ‘attention to detail’ in the autism spectrum quotient showed lower activation of the left frontotemporal area during the two tasks. The patients with SCZ showed significantly reduced activation, compared to healthy subjects, and greater activation, compared to patients with ASD, in the area during the verbal fluency task. The patients with SCZ with more severe symptoms had lower brain activation during the task in this area. Our results suggest that two distinct areas are involved in the distinctive brain pathophysiology relevant to cognitive processing in patients with ASD and SCZ.

Is interference control in children with specific language impairment similar to that of children with autistic spectrum disorder?

AIMS

The purpose of the study was to examine resistance to proactive interference, which is strongly associated with working memory (WM) performance and language processing, in children with specific language impairment (SLI), with autism spectrum disorder (ASD), and with typical development (TD).

METHODS

Sixty children (eight to ten years; matched in age and nonverbal IQ) participated in the study. Resistance to proactive interference was measured using a verbal conflict paradigm.

RESULTS

Children with SLI and ASD show a deficit in resistance to proactive interference compared to their TD peers, but the source of the problem appears to be different for the two clinical groups. The interference problem exhibited by the children with SLI is related to a more complex deficit involving different cognitive-linguistic functions, whereas the children with ASD show a specific problem in cognitive flexibility.

IMPLICATIONS

The theoretical implications are that poor resistance to interference may be caused by weaknesses in different WM functions, such as a deficit in updating or responses based on familiarity rather than recollection. The clinical implications are that children with SLI and ASD show distinct patterns of performance; therefore they need different types of intervention to strengthen their resistance to proactive interference.

Formal Thought Disorder and Executive Functioning in Children and Adolescents with Autism Spectrum Disorder: Old Leads and New Avenues

Formal thought disorder (FTD) is a disruption in the flow of thought and a common feature in psychotic disorders and autism spectrum disorder (ASD). Executive dysfunction has often been associated with FTD, yet for ASD convincing evidence is lacking. This study investigated FTD and three core executive functions in 50 young children and adolescents with high-functioning ASD and 56 matched controls. Higher overall levels of FTD marked ASD compared to controls. Furthermore, in ASD decreased performance on verbal working memory was correlated with increased FTD ratings and explained a significant amount of variance of objective and subjective FTD. Verbal working memory is currently the most promising target executive function for understanding the development of idiosyncratic thought disorders in ASD.

Dissociation of Brain Activation in Autism and Schizotypal Personality Disorder During Social Judgments

Background

There are overlaps between autism and schizophrenia but these are particularly pronounced, especially in social domains, for higher functioning individuals with autism spectrum disorders (ASD) or schizotypal personality disorder (SPD). It is not known whether these overlapping social deficits result from shared or distinct brain mechanisms. We therefore compared social cognition in ASD and SPD using functional magnetic resonance imaging (fMRI).

Methods

Twenty-one individuals with SPD, 28 with ASD and 33 controls were compared with respect to clinical symptoms using the Positive and Negative Syndrome Scale; social cognition, using a social judgment task and Ekman 60 faces task; and brain activation using an fMRI task of social judgment.

Results

The ASD and SPD groups showed few differences in symptoms or social cognition. However, fMRI showed that, compared to ASD, the SPD group showed significantly greater activation during social compared to gender judgments in the amygdala and 3 clusters: right posterior cerebellum, extending into fusiform and inferior temporal gyri; left posterior cerebellum; and left intraparietal sulcus extending through medial portions of the temporal gyri into the fusiform gyrus (all P < .05 family-wise error corrected). Control activations lay between the ASD and SPD groups.

Conclusions

Although social cognitive deficits in ASD and SPD appear superficially similar they are the result of different brain mechanisms. These findings have implications for therapeutic interventions targeted at social dysfunction in these conditions.

Stop and change: inhibition and flexibility skills are related to repetitive behavior in children and young adults with autism spectrum disorders

Cognitive control dysfunctions, like inhibitory and attentional flexibility deficits are assumed to underlie repetitive behavior in individuals with autism spectrum disorders (ASD). In the present study, prepotent response inhibition and attentional flexibility were examined in 64 high-functioning individuals with ASD and 53 control participants. Performance under different task conditions were tested both in response to visual and auditory information, and requiring a motor or verbal response. Individuals with ASD showed significant more control dysfunctions than typically developing participants on the auditory computer task. Inhibitory control and attentional flexibility predicted RRB in everyday life. Specifically, response inhibition in reaction to visual information and task switching in reaction to auditory information predicted motor and sensory stereotyped behavior.

Prepotent response inhibition and interference control in autism spectrum disorders: two meta-analyses

There is a substantial amount of data providing evidence for, but also against the hypothesis that individuals with autism spectrum disorders (ASD) encounter inhibitory control deficits. ASD is often associated with interference control deficits rather than prepotent response inhibition. Moreover, the developmental trajectory for these inhibitory control processes is hypothesized to differ in ASD as compared to typical development. In efforts to gain a more comprehensive perspective of inhibition in ASD, separate quantitative analysis for prepotent response inhibition studies and interference control studies were conducted. Together, these two meta-analyses included 41 studies with a combined sample size of 1,091 people with ASD (M age 14.8 years), and 1,306 typically developing (TD) controls (M age 13.8 years).The meta-analyses indicated that individuals with ASD show increased difficulties in prepotent response inhibition (effect size 0.55) and in interference control (effect size 0.31). In addition, age was a relevant moderator for prepotent response inhibition but not for interference control. Exploratory analyses revealed that when IQ was taken into account, heterogeneity considerably decreased among interference control studies but not among prepotent response inhibition. In contrast to the general belief, both prepotent response inhibition and interference control problems were observed in individuals with ASD. However, a large variation between studies was also found. Therefore, there remain factors beyond inhibition type, age, or IQ that significantly influence inhibitory control performance among individuals with ASD.

Development of schizotypal symptoms following psychiatric disorders in childhood or adolescence

It was examined how juvenile psychiatric disorders and adult schizotypal symptoms are associated. 731 patients of the Department of Child and Adolescent Psychiatry of the University Medical Centre Utrecht, the Netherlands, with mean age of 12.1 years (SD = 4.0) were reassessed at the mean age of 27.9 years (SD = 5.7) for adult schizotypal symptoms using the Schizotypal Personality Questionnaire-Revised (Vollema, Schizophr Bull 26(3):565-575, 2000). Differences between 13 juvenile DSM categories and normal controls (n = 80) on adult schizotypal total and factor scores were analyzed, using (M)ANCOVA. Pervasive developmental disorders (PDD), attention deficit hyperactivity disorders (ADHD), deferred diagnosis, sexual and gender identity disorders and depressive disorders had higher SPQ total scores when compared to normal controls (p < 0.001). Higher levels of disorganized schizotypal symptoms were found for PDD, ADHD, and deferred diagnosis (p < 0.001). The same diagnostic groups showed higher level of negative schizotypal symptoms, which was likewise true for sexual and gender identity disorders, depressive disorders, disruptive disorders, and the category of 'Other conditions that may be a focus of clinical attention' (p < 0.001). No differences with normal controls were found for adult positive schizotypal symptoms (p < 0.110). The current findings are suggestive of the idea that psychiatric disorders in childhood or adolescence are a more general expression of a liability to schizophrenia spectrum pathology in future life. In addition, specific patterns of adult schizotypal symptomatology are associated with different types of juvenile psychiatric disorder.