Autistic individuals are twice as likely to meet criteria for anxiety than neurotypical children; yet we lack understanding of early presentations of anxiety in young autistic children, especially those with cognitive impairment. This study is the first to utilize an autism-specific anxiety diagnostic interview with 28 preschool cognitively…

The aim of this study was to compare the rates of psychotropic medication use and psychotropic polypharmacy between autistic adults with and without intellectual disability (ID) and to examine factors associated with psychotropic medication use and psychotropic polypharmacy in autistic adults, stratified by the presence of ID. We conducted a…

Skin picking is highly prevalent in people with Prader-Willi syndrome (PWS). This study addressed the temporal (frequency, duration) and wider characteristics (e.g. type of skin picked, apparent motivations, or management strategies) of skin picking to inform intervention strategies. Nineteen parents/carers who observe skin picking shown by the…

This article comprehensively reviews motor impairments in children with autism spectrum disorder (ASD) to: (1) determine the prevalence of motor problems in children with ASD; (2) understand the nature of motor difficulties in ASD and whether they are consistent with developmental coordination disorder (DCD); and (3) determine if the term DCD was…

Intellectual disability in India is substantially under-reported, especially amongst females. This study quantifies the prevalence and gender bias in household reporting of intellectual disability by estimating the age-and-gender specific prevalence of the intellectually disabled by education, Socio-Demographic Index (SDI) score, place of…

A systematic literature review was undertaken to ascertain the prevalence of self-harm and suicidal behaviour in children and young people under 18 years old with a diagnosis of autism spectrum disorder (ASD), with or without an intellectual disability. There was variation in the reported prevalence rates but results suggested that rates of both…

Anxiety is common in children with ASD; however, the burden of specific anxiety disorders for adults with ASD is under-researched. Using the Stockholm Youth Cohort, we compared anxiety disorder diagnoses among autistic adults (n = 4049), with or without intellectual disability, and population controls (n = 217,645). We conducted additional sibling…

We examined special education classifications among students aged 3-21 in North Carolina public schools, highlighting autism spectrum disorder (ASD) and intellectual disability (ID). Results revealed variability by county in ASD and ID prevalence, and in county-level ratios of ID vs. ASD classifications. Sociodemographic characteristics predicted…

We reviewed federal special education data to determine school-identified prevalence of Autism Spectrum Disorder (ASD) and other disability categories by U.S. state. We also examined whether state-level policies, demographic factors, and rates of other eligibility categories are predictive of these state ASD rates. Results indicate that overall, 1…

Self-injurious behaviour is purportedly common in autism, but prevalence rates have not yet been synthesised meta-analytically. In the present study, data from 14,379 participants in thirty-seven papers were analysed to generate a pooled prevalence estimate of self-injury in autism of 42% (confidence intervals 0.38-0.47). Hand-hitting topography…

We estimated autism spectrum disorder (ASD) prevalence in 7-9 year-old children in 2015 using data from three nationwide health registry systems (Denmark, Finland, Iceland) and two French population-based regional registries. Prevalence ranged from 0.48% in South-East France to 3.13% in Iceland (South-West France: 0.73%, Finland: 0.77%, Denmark:…

Individuals with specific genetic syndromes associated with intellectual disability (ID), such as Williams syndrome (WS), are at increased risk for developing anxiety disorders. A systematic literature review identified sixteen WS papers that could generate pooled prevalence estimates of anxiety disorders for WS. A meta-analysis compared these…

The prevalence and risk of foster care involvement among children with autism spectrum disorder (ASD) relative to children with intellectual disability (ID), children with ASD and ID, and typically developing children were examined using 2001-2007 Medicaid data. Children were followed up to the first foster care placement or until the end of 2007;…

Time trends in autism spectrum disorder (ASD) and intellectual disability (ID) prevalence from the United States Individuals with Disabilities Education Act data were computed from 2000 to 2011 for each state and each age from 6 to 17. These trends did not support the hypothesis that diagnostic substitution for ID can explain the ASD rise over…

Self-injurious and aggressive behaviors are common in fragile X syndrome (FXS). However, little is known about the persistence of these behaviors and associated risk markers. We established the prevalence and persistence of self-injurious and aggressive behaviors over eight years in males with FXS, and associations with risk markers. Results…