1. Hallett V, Ronald A, Happe F. {{Investigating the Association Between Autistic-Like and Internalizing Traits in a Community-Based Twin Sample}}. {J Am Acad Child Adolesc Psychiatry};2009 (Apr 24)
OBJECTIVES:: Recent research has suggested that children with autistic spectrum disorders often experience comorbid symptoms of anxiety and depression. However, despite this overlap, no quantitative genetic studies have addressed the phenotypic overlap and the etiologic association between internalizing and autistic-like traits within the general population. This study aimed to investigate the phenotypic and etiologic relation between internalizing and autistic-like traits using a community-based twin sample. METHOD:: We investigated the co-occurrence of these traits in a population-based sample of 3,233 twin pairs aged 8 to 9 years, using both parent- and teacher-report questionnaires. Bivariate structural equation modeling techniques were used to determine the extent to which internalizing and autistic-like traits shared common genetic and environmental influences. RESULTS:: Our results showed that there was a modest phenotypic correlation (r = 0.26-0.29) between autistic-like and internalizing traits. The traits were both substantially heritable but were largely independent with regard to their genetic influences (rG = 0.12-0.19). Shared environmental influences were modest but were largely common to both traits. Similar results were found using both parent- and teacher-reported data. CONCLUSIONS:: Internalizing and autistic-like traits showed moderate phenotypic overlap within the general population. This association was explained in small part by shared genetic factors, but the results suggested that most genetic influences were specific to either internalizing traits or autistic traits. Given these findings, we discuss the potential mechanisms that may underlie the relation between these traits.
2. Magnee MJ, Oranje B, van Engeland H, Kahn RS, Kemner C. {{Cross-sensory gating in schizophrenia and autism spectrum disorder: EEG evidence for impaired brain connectivity?}} {Neuropsychologia};2009 (Jun);47(7):1728-1732.
Autism spectrum disorders (ASD) and schizophrenia are both neurodevelopmental disorders that have extensively been associated with impairments in functional brain connectivity. Using a cross-sensory P50 suppression paradigm, this study investigated low-level audiovisual interactions on cortical EEG activation, which provides crucial information about functional integrity of connections between brain areas involved in cross-sensory processing in both disorders. Thirteen high functioning adult males with ASD, 13 high functioning adult males with schizophrenia, and 16 healthy adult males participated in the study. No differences in neither auditory nor cross-sensory P50 suppression were found between healthy controls and individuals with ASD. In schizophrenia, attenuated P50 responses to the first auditory stimulus indicated early auditory processing deficits. These results are in accordance with the notion that filtering deficits may be secondary to earlier sensory dysfunction. Also, atypical cross-sensory suppression was found, which implies that the cognitive impairments seen in schizophrenia may be due to deficits in the integrity of connections between brain areas involved in low-level cross-sensory processing.
3. Richdale AL, Schreck KA. {{Sleep problems in autism spectrum disorders: Prevalence, nature, and possible biopsychosocial aetiologies}}. {Sleep Med Rev};2009 (Apr 22)
As considerably more people are diagnosed with an autism spectrum disorder (ASD), interest in the associated behaviours, including sleep problems has increased. This has resulted in a subsequent increase in the research related to the sleep problems occurring in people with an ASD. This article summarizes and evaluates the current literature related to a) the higher prevalence of a sleep problem compared to typically developing children, b) the specific types of sleep problems for people with an ASD, and c) the possible aetiology of sleep problems in the ASDs within a biopsychosocial framework. It is concluded that recent studies confirm that the majority of this population are likely to experience sleep difficulties, with settling issues in children with an ASD the most commonly reported. However, exploration of the types of sleep difficulties and associated aetiological factors in the ASDs is still in its infancy.
