In educational systems around the world, there is a long tradition of using psychiatric diagnoses when providing support in the special educational field. For instance, many countries have special schools and special classes for students with psychiatric diagnoses such as Attention-Deficit Hyperactivity Disorder, Autism spectrum disorder and…

Introduction: The purpose of this study was to gain additional insight on patterns of behavior of three individuals dually diagnosed with intellectual disability (ID) and bipolar disorder as they cycled between elevated and depressed mood states. Methods: Data were collected from weekly, one-hour observations across a period of several months. The…

Attention-deficit/hyperactivity disorder is one of the most common comorbidities in individuals with autism spectrum disorder. However, the clinical implications of the co-occurrence of these two disorders are still poorly understood. Based on a preregistered protocol (PROSPERO CRD42020193880), this systematic review identified 34 articles,…

Substance use disorders are considered externalizing disorders, defined by anti-social and impulsive behavior, as opposed to internalizing disorders, defined by anxious and depressive thinking; however, that strict binary is increasingly untenable. In this dissertation, I evaluate the co-development of internalizing and externalizing symptoms…

Although global associations between language and behavioral development are well established, relations among components and subgroups within these disorders remain unclear. The primary aim of this study was to explore whether language components differed by behavioral subtypes: internalizing only, externalizing only, or both. To control for…

Background: Epilepsy and challenging behaviour are both highly prevalent in the intellectual disability (ID) population and it is thus crucial to understand any possible associations between the two. Method: PsycINFO, MEDLINE, Embase, CINAHL and Web of Science were searched for quantitative data about epilepsy and any forms of challenging…

This study investigated the utility of including teacher-reported callous-unemotional (CU) behaviors in the assessment of disruptive behaviors in school-based research. Participants included 138 first- and second-grade children (68% male; 76% eligible for free or reduced-price lunch; 61% Black, 9% Latinx, 23% White, and 7% multiracial) who…

Social communication and executive functioning challenges as well as co-occurring anxiety/depression may make acquiring the skills needed to manage daily life tasks difficult for diploma-track autistic youth, thus limiting their participation in adult roles. This study describes the associations between executive function, social communication…

Objective: ADHD is a commonly diagnosed neurodevelopmental disorder in the U.S., with symptoms including hyperactivity, inattention, and impulsivity. These symptoms can lead to increased engagement in unhealthy behaviors. The current study examined the associations between health risk factors and ADHD among a community-based sample of 345 students…

Introduction: Individuals with Down syndrome (DS) and IDD have lower psychiatric disorders rates than other individuals with IDD, and more information is needed about possible unique mental health needs of this group. Method: De-identified intake data for individuals with IDD, 101 with DS (mean age 27) and 4,366 without DS (mean age 25) served in…

Background: The aim was to investigate the aggressive behavior of young people in specialized institutions with intellectual disability (ID) with or without autism spectrum disorder (ASD). Method: Data on 305 institutionalized young people were collected using two aggression scales, the 'Children's Scale of Hostility and Aggression:…

Behavioral inflexibility (BI) has been highlighted to occur across genetic and neurodevelopmental disorders. This study characterized BI in two common neurogenetic conditions: Fragile X syndrome (FXS) and Down syndrome (DS). Caregivers of children with FXS (N = 56; with ASD = 28; FXS only = 28) and DS (N = 146) completed the Behavioral…

Autism spectrum disorder and anxiety are highly comorbid conditions. Understanding the underlying traits of anxiety in autism spectrum disorder is crucial to prevent and treat it efficiently. Hence, this study determined whether social communication difficulties or restricted repetitive behaviors are stronger risk factors for anxiety symptoms in…

Self-injurious behavior (SIB) occurs in up to 50% of individuals with autism. As one of the most serious conditions in individuals with developmental disabilities, SIB affects the individual and his or her family in multiple contexts. A systematic analysis of factors most commonly associated with SIB could inform the development of individualized…

For all children and youth, language underpins success in academic, social, and behavioral interactions. For students with language deficits, even seemingly simple tasks can be challenging and frustrating. Perhaps not surprising, children with language deficits often exhibit high rates of problem behavior, and children with behavior disorders tend…