Objective: Attention Deficit Hyperactivity Disorder (ADHD) is a common co-occurring condition in autistic individuals. ADHD is sometimes first recognised in young adulthood because ADHD symptoms may be misattributed to autism due to superficial overlap in presentation and diagnostic overshadowing. It should be investigated whether ADHD…

Anxiety is a common and impairing problem in children with autism spectrum disorder, but little is known about it in preschool children with autism spectrum disorder. This article reports on the characteristics of anxiety symptoms in young children with autism spectrum disorder using a parent-completed rating scale. One hundred and eighty children…

Individuals with autism spectrum disorder are more likely than typically developing individuals to experience a range of gastrointestinal abnormalities, including chronic diarrhea, constipation, food sensitivities, and abdominal pain. These gastrointestinal symptoms have been associated with higher levels of irritability and aggressive behavior,…

Longitudinal data on the functioning of adults referred for possible autism as children are sparse and possibly different from datasets consisting of adult clinical referrals. A total of 123 young adults, mean age of 26, referred for neurodevelopmental disorders in early childhood were categorized into three outcome groups: autism spectrum…

The newest edition of the "Diagnostic and Statistical Manual of Mental Disorders" (5th ed., DSM-5) introduced substantial changes to the diagnostic criteria for autism spectrum disorder, including new severity level ratings for social communication and restricted and repetitive behavior domains. The purpose of this study was to evaluate…

Introduction: Although the Aberrant Behavior Checklist (ABC) is one of the most widely used behavioral rating scales among people with developmental disabilities, very few studies have examined the factor structure of the non-English versions. Methods: The construct validity of the Norwegian ABC was examined in a clinical sample of children and…

Epilepsy is common in children with autism spectrum disorder (ASD) but little is known about how seizures impact the autism phenotype. The association between epilepsy and autism symptoms and associated maladaptive behaviors was examined in 2,645 children with ASD, of whom 139 had epilepsy, from the Simons Simplex Collection. Children with ASD and…

Background: Attention deficit hyperactivity disorder is increased in children with intellectual disability. Previous research has suggested stimulants are less effective than in typically developing children but no studies have titrated medication for individual optimal dosing or tested the effects for longer than 4 weeks. Method: One hundred and…

Background: Presence of an autism spectrum disorder is a risk factor for development of self-injurious behaviour (SIB) exhibited by individuals with developmental disorders. The most salient SIB risk factors historically studied within developmental disorders are level of intellectual disability, communication deficits and presence of specific…

Previously, we adapted the Home Situations Questionnaire to measure behavioral non-compliance in everyday settings in children with pervasive developmental disorders. In this study, we further revised this instrument for use in autism spectrum disorder and examined its psychometric properties (referred to as the Home Situations…