There is increasing concern regarding additional psychiatric problems that co-occur with Autism Spectrum Disorder (ASD), as reflected in recent changes to diagnostic schemes. However, there remains little research with population-based samples across childhood. We report on additional problems, as measured by the Strengths and Difficulties…

There is a growing body of opinion that we should view autism as fractionable into different, largely independent sets of clinical features. The alternative view is that autism is a coherent syndrome in which principal features of the disorder stand in intimate developmental relationship with each other. Studies of congenitally blind children…

Background: The behavioural symptoms of autism spectrum disorder (ASD) are thought to reflect underlying cognitive deficits/differences. The findings in the literature are somewhat mixed regarding the cognitive features of ASD. This study attempted to address this issue by investigating a range of cognitive deficits and the prevalence of multiple…

The present study examined genetic and shared environment contributions to quantitatively-measured autism symptoms and categorically-defined autism spectrum disorders (ASD). Participants included 568 twins from the Interactive Autism Network. Autism symptoms were obtained using the Social Communication Questionnaire and Social Responsiveness…

Internalizing difficulties are prevalent in children with autism spectrum disorders (ASD), yet little is known about the underlying cause of this comorbidity. It is also unclear which types of autistic-like and internalizing difficulties are most strongly associated. The current study investigated the phenotypic and etiological associations…

The phenotypic and etiologic relation between internalizing and autistic-like traits is studied using a community-based twin sample. Internalizing and autistic-like traits showed moderate phenotypic overlap but have specific genetic influences.

Background: Although impaired sensory processing accompanies various clinical conditions, the question of its status as an independent disorder remains open. Our goal was to delineate the comorbidity (or lack thereof) between childhood psychopathology and sensory over-responsivity (SOR) in middle childhood using phenotypic and behavior-genetic…

Factor structure and relationship between core features of autism (social impairments, communication difficulties, and restricted, repetitive behaviours or interests (RRBIs)) were explored in 189 children from the Twins Early Development Study, diagnosed with autistic spectrum disorders (ASDs) using the Development and Wellbeing Assessment (DAWBA;…

Autism spectrum disorders (ASDs) are diagnosed when individuals show impairments in three behavioural domains: communication, social interactions, and repetitive, restrictive behaviours and interests (RRBIs). Recent data suggest that these three sets of behaviours are genetically heterogeneous. Early language delay is strongly associated with ASD,…

The first case study of identical male twins concordant for DSM-IV Asperger's disorder (ASD) was presented. Their monozygocity was confirmed by short tandem repeat analyses with a probability of 99.999963%. Despite sharing the same DNA and environment, the twins are different in comorbidity (i.e., major depressive disorder in the elder and absence…

Objective: This study investigated the etiology of autistic-like traits in the general population and the etiological overlap between the three aspects of the triad of impairments (social impairments, communication impairments, restricted repetitive behaviors and interests) that together define autism spectrum disorders. Method: Parents of 3,400…