Carrie Allison

Prevalence of autism-spectrum conditions: UK school-based population study

BACKGROUND Recent reports estimate the prevalence of autism-spectrum conditions in the UK to be 1%. AIMS To use different methods to estimate the prevalence of autism-spectrum conditions, including previously undiagnosed cases, in Cambridgeshire. METHOD We carried out a survey of autism-spectrum conditions using the Special Educational Needs (SEN) register. A diagnosis survey was distributed to participating schools to be handed out to parents of all children aged 5-9 years. The mainstream primary school population was screened for unknown cases. RESULTS The prevalence estimates generated from the SEN register and diagnosis survey were 94 per 10 000 and 99 per 10 000 respectively. A total of 11 children received a research diagnosis of an autism-spectrum condition following screening and assessment. The ratio of known:unknown cases is about 3:2 (following statistical weighting procedures). Taken together, we estimate the prevalence to be 157 per 10 000, including previously undiagnosed cases. CONCLUSIONS This study has implications for planning diagnostic, social and health services.

The CAST (Childhood Asperger Syndrome Test) Test accuracy

The Childhood Asperger Syndrome Test (CAST) is a parental questionnaire to screen for autism spectrum conditions. In this validation study, the CAST was distributed to 1925 children aged 5-11 in mainstream Cambridgeshire schools. A sample of participants received a full diagnostic assessment, conducted blind to screen status. The sensitivity of the CAST, at a designated cut-point of 15, was 100 percent, the specificity was 97 percent and the positive predictive value was 50 percent, using the group’s consensus diagnosis as the gold standard. The accuracy indices varied with the case definition used. The sensitivity of the accuracy statistics to case definition and to missing data was explored. The CAST is useful as a screening test for autism spectrum conditions in epidemiological research. There is not currently enough evidence to recommend the use of the CAST as a screening test within a public health screening programme in the general population.

Cognition in males and females with autism: similarities and differences.

The male bias in autism spectrum conditions (ASC) has led to females with ASC being under-researched. This lack of attention to females could hide variability due to sex that may explain some of the heterogeneity within ASC. In this study we investigate four key cognitive domains (mentalizing and emotion perception, executive function, perceptual attention to detail, and motor function) in ASC, to test for similarities and differences between males and females with and without ASC (n = 128 adults; n = 32 per group). In the mentalizing and facial emotion perception domain, males and females with ASC showed similar deficits compared to neurotypical controls. However, in attention to detail and dexterity involving executive function, although males with ASC showed poorer performance relative to neurotypical males, females with ASC performed comparably to neurotypical females. We conclude that performance in the social-cognitive domain is equally impaired in male and female adults with ASC. However, in specific non-social cognitive domains, performance within ASC depends on sex. This suggests that in specific domains, cognitive profiles in ASC are modulated by sex.

Suicidal ideation and suicide plans or attempts in adults with Asperger's syndrome attending a specialist diagnostic clinic: a clinical cohort study

BACKGROUND Aspergers syndrome in adulthood is frequently associated with depression, but few studies have explored the lifetime experience of self-reported suicidal ideation and suicide plans or attempts in this clinical group. We aimed to assess this prevalence in a clinical cohort of patients in the UK. METHOD In a clinical cohort study, we undertook a retrospective analysis of clinical survey data from adults newly diagnosed with Aspergers syndrome at a specialist diagnostic clinic between Jan 23, 2004, and July 8, 2013, in England. Patients completed a self-report questionnaire before clinical assessment, recording lifetime experience of depression, suicidal ideation, and suicide plans or attempts, along with self-reported measures of autistic traits and empathy. We compared the rate of suicidal ideation in the sample with published rates of suicidal ideation in the general population and other clinical groups. We also assessed associations between depression, autistic traits, empathy, and likelihood of suicidal ideation and suicide plans or attempts. FINDINGS 374 adults (256 men and 118 women) were diagnosed with Aspergers syndrome in the study period. 243 (66%) of 367 respondents self-reported suicidal ideation, 127 (35%) of 365 respondents self-reported plans or attempts at suicide, and 116 (31%) of 368 respondents self-reported depression. Adults with Aspergers syndrome were significantly more likely to report lifetime experience of suicidal ideation than were individuals from a general UK population sample (odds ratio 9·6 [95% CI 7·6-11·9], p<0·0001), people with one, two, or more medical illnesses (p<0·0001), or people with psychotic illness (p=0·019). Compared with people diagnosed with Aspergers syndrome without depression, people with Aspergers syndrome and depression were more likely to report suicidal ideation (p<0·0001) and suicide plans or attempts (p<0·0001). INTERPRETATION Our findings lend support to anecdotal reports of increased rates of suicidal ideation in adults with Aspergers syndrome, and depression as an important potential risk factor for suicidality in adults with this condition. Because adults with Aspergers syndrome often have many risk factors for secondary depression (eg, social isolation or exclusion, and unemployment), our findings emphasise the need for appropriate service planning and support to reduce risk in this clinical group. FUNDING The Three Guineas Trust, the Baily Thomas Foundation, the Medical Research Council, NIHR-CLAHRC-EoE, Cambridgeshire and Peterborough NHS Foundation Trust (CPFT), and the Autism Research Trust.

Do girls with anorexia nervosa have elevated autistic traits

BackgroundPatients with anorexia may have elevated autistic traits. In this study, we tested test whether patients with anorexia nervosa (anorexia) have an elevated score on a dimensional measure of autistic traits, the Autism Spectrum Quotient (AQ), as well as on trait measures relevant to the autism spectrum: the Empathy Quotient (EQ), and the Systemizing Quotient (SQ).MethodsTwo groups were tested: (1) female adolescents with anorexia: n = 66, aged 12 to 18 years; and (2) female adolescents without anorexia: n =1,609, aged 12 to 18 years. Both groups were tested using the AQ, EQ, and SQ, via the parent-report adolescent versions for patients aged 12 to 15 years old, and the self-report adult versions for patients aged over 16 years.ResultsAs predicted, the patients with anorexia had a higher AQ and SQ. Their EQ score was reduced, but only for the parent-report version in the younger age group. Using EQ-SQ scores to calculate ‘cognitive types’, patients with anorexia were more likely to show the Type S profile (systemizing (S) better than empathy (E)), compared with typical females.ConclusionsFemales with anorexia have elevated autistic traits. Clinicians should consider if a focus on autistic traits might be helpful in the assessment and treatment of anorexia. Future research needs to establish if these results reflect traits or states associated with anorexia.

The Childhood Asperger Syndrome Test (CAST) Test–retest reliability

The Childhood Asperger Syndrome Test (CAST) is a 37-item parental self-completion questionnaire to screen for autism spectrum conditions in research. Good test accuracy was demonstrated in studies with primary school aged children in mainstream schools. The aim of this study was to investigate the test–retest reliability of the CAST. Parents of 1000 children in years 1–6 in five mainstream primary schools in Cambridgeshire received the CAST. A second identical questionnaire was posted to respondents after approximately 2 weeks. Both mailings generated 136 responses. Agreement above and below a screening cut-point of 15 was investigated.The kappa statistic for agreement (< 15 versus ≥ 15) was 0.70, and 97 percent (95 percent CI: 93–99 percent) of children did not move across the cut-point of 15. The correlation between the two test scores was 0.83 (Spearmans rho).The CAST has shown good test–retest reliability, and now requires further investigation in a high-scoring sample.

Is synaesthesia more common in autism

BackgroundSynaesthesia is a neurodevelopmental condition in which a sensation in one modality triggers a perception in a second modality. Autism (shorthand for Autism Spectrum Conditions) is a neurodevelopmental condition involving social-communication disability alongside resistance to change and unusually narrow interests or activities. Whilst on the surface they appear distinct, they have been suggested to share common atypical neural connectivity.MethodsIn the present study, we carried out the first prevalence study of synaesthesia in autism to formally test whether these conditions are independent. After exclusions, 164 adults with autism and 97 controls completed a synaesthesia questionnaire, Autism Spectrum Quotient, and Test of Genuineness-Revised (ToG-R) online.ResultsThe rate of synaesthesia in adults with autism was 18.9% (31 out of 164), almost three times greater than in controls (7.22%, 7 out of 97, P<0.05). ToG-R proved unsuitable for synaesthetes with autism.ConclusionsThe significant increase in synaesthesia prevalence in autism suggests that the two conditions may share some common underlying mechanisms. Future research is needed to develop more feasible validation methods of synaesthesia in autism.

The Childhood Asperger Syndrome Test (CAST) Test–retest reliability in a high scoring sample

The Childhood Asperger Syndrome Test (CAST) is a 37-item parental self-completion questionnaire designed to screen for high-functioning autism spectrum conditions in epidemiological research. The CAST has previously demonstrated good accuracy for use as a screening test, with high sensitivity in studies with primary school aged children in mainstream schools. This study aimed to investigate test–retest reliability of the CAST in a high scoring sample. To this end, 73 parents filled in the second CAST (CAST-2) within approximately 2 months of the first administration of the CAST (CAST-1). Agreement above and below the cut-point of 15 was investigated. The kappa statistic for agreement (<15 versus ≥15) was 0.41. It was found that 70 percent (95% CI: 58, 80) of children did not move across the cut-point of 15. The correlation between the two test scores was 0.67 (Spearmans rho). The CAST shows moderate test–retest reliability in a high scoring sample, further evidence that it is a relatively robust screening tool for epidemiological research.

Are Autism Spectrum Conditions More Prevalent in an Information-Technology Region? A School-Based Study of Three Regions in the Netherlands

We tested for differences in the prevalence of autism spectrum conditions (ASC) in school-aged children in three geographical regions in the Netherlands. Schools were asked to provide the number of children enrolled, the number having a clinical diagnosis of ASC and/or two control neurodevelopmental conditions. Prevalence was evaluated by negative binomial regression and adjustments were made for non-response and size of the schools. The prevalence estimates of ASC in Eindhoven was 229 per 10,000, significantly higher than in Haarlem (84 per 10,000) and Utrecht (57 per 10,000), whilst the prevalence for the control conditions were similar in all regions. Phase two is planned to validate school-reported cases using standardized diagnostic methods and to explore the possible causes for these differences.

Empathizing, systemizing, and autistic traits : latent structure in individuals with autism, their parents, and general population controls

The search for genes involved in autism spectrum conditions (ASC) may have been hindered by the assumption that the different symptoms that define the condition can be attributed to the same causal mechanism. Instead the social and nonsocial aspects of ASC may have distinct causes at genetic, cognitive, and neural levels. It has been posited that the core features of ASC can be explained by a deficit in empathizing alongside intact or superior systemizing; the drive to understand and derive rules about a system. First-degree relatives also show some mild manifestations that parallel the defining features of ASC, termed the broader autism phenotype. Factor analyses were conducted to assess whether the latent structure of empathizing, systemizing, and autistic traits differs across samples with a high (individuals on the spectrum), medium (first-degree relatives) or low (general population controls) genetic vulnerability to autism. Results highlighted a two-factor model, confirming an empathizing and a systemizing factor. The relationship between these two factors was significantly stronger in first-degree relatives and the autism group compared with controls. The same model provided the best fit among the three groups, suggesting a similar latent structure irrespective of genetic vulnerability. However, results also suggest that although these traits are relatively independent in the general population, they are substantially correlated in individuals with ASC and their parents. This implies that there is substantially more overlap between systemizing and empathizing among individuals with an increased genetic liability to autism. This has potential implications for the genetic, environmental, and cognitive explanations of autism spectrum conditions.