Psychiatric disorders in individuals with co-occurring autism spectrum disorders (ASD) and intellectual disability (ID) are common, but diagnosis presents many challenges. The Psychopathology in Autism checklist (PAC) is among the very few instruments specifically developed for this group of individuals. The psychometric properties of the PAC…

Background: The diagnosis of depression in severe and profound intellectual disability is challenging. Without adequate skills in verbal self-expression, standardized diagnostic criteria cannot be used with confidence. The purpose of this systematic review was to investigate the assessment and diagnosis of unipolar depression in severe and…

Although some literature reviews cited mixed results for group-based social competence interventions in schools, existing descriptions of intervention efficacy often lack attention on important factors that may moderate differential response. Some studies suggest that individual characteristics such as diagnosis (i.e., specific deficit clusters)…

The purpose of this study was to investigate the self-perception bias (SPB) in adolescents with attention-deficit hyperactivity disorder (ADHD). The SPB was defined as adolescent underestimation of their learning and behavior problems in comparison to parent- or teacher-reports or a standardized achievement test. The sample comprised 74…

We examined the extent to which children's skilled understanding and production of appropriate language (verbal ability) may relate to their peer functioning. Participants included two independent samples of children with and without Attention-Deficit/Hyperactivity Disorder (ADHD; Study 1, N = 124; Study 2, N = 137) who were administered a…

"The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5)," requires that symptoms of ADHD must be "developmentally inappropriate" in order for an ADHD diagnosis to be considered. Because the DSM-5 does not specifically outline procedure for determining developmental inappropriateness of behaviors,…

Hierarchical cluster analyses were used to detect three subgroups in a sample of children with pervasive developmental disorder--not otherwise specified (PDD-NOS) evaluated at ages 2 and 4. At age 2, Cluster 1 demonstrated few autism symptoms and high cognitive scores; 60% no longer met criteria for PDD at 4. Cluster 2 exhibited more autism…

Background: Social (pragmatic) communication disorder (SPCD) is a new diagnosis introduced by DSM-5, characterised by problems with verbal and nonverbal social communication. It is currently unclear whether SPCD is a valid diagnostic category, because little is known about the characteristics of those who meet its criteria. We sought to identify…

Background: Evidence from Western countries indicates marked increases in diagnosis and treatment of childhood psychiatric disorders in recent years. These could reflect changes in prevalence of mental health problems, changes in their impact or increased clinical recognition and help-seeking. Epidemiological cross-cohort comparisons are required…

This study assessed the diagnostic utility of the Pervasive Developmental Disorder Behavior Inventory (PDDBI) in a sample of 84 children aged 3-12 years of age. Forty-two children with ASD were individually matched on age and non-verbal IQ to 42 children with other disabilities and groups were compared on PDDBI subscales and total score. Results…

Background: Diagnosis of "specific" language impairment traditionally required nonverbal IQ to be within normal limits, often resulting in restricted access to clinical services for children with lower NVIQ. Changes to DSM-5 criteria for language disorder removed this NVIQ requirement. This study sought to delineate the impact of varying…

Before the 1990s, research on the early identification and prevention of severe behavior disorders (SBDs), such as aggression, self-injury, and stereotyped behavior, among young children with intellectual and developmental disabilities (IDD), was mostly done with children 3 years or older. More recent work suggests that signs of SBDs may occur as…

Previous studies have highlighted a high level of language impairment (LI) and pragmatic language disorder (PLD) amongst children with social, emotional and behavioural difficulties (SEBD). However, little is known regarding the impact of LI in the severity of PLD in this group. This study investigates the language and pragmatic language skills of…

This prospective study of the FIRST WORDS® Project examined restricted and repetitive behaviors in a sample of 55 toddlers at a mean age of 20 months who were later diagnosed with autism spectrum disorder. Restricted and repetitive behaviors were coded using the Repetitive Movement and Restricted Interest Scales in two video-recorded observation…

Background: Quality assessment of children's functioning is critical for both research and service delivery. The Strengths and Difficulties Questionnaire (SDQ) is a brief, publicly-available instrument that provides such assessment. Although the SDQ has strong psychometric properties, less is known about its responsiveness or sensitivity to…