Peter Szatmari

University of Toronto | U of T · Department of Psychiatry

Youth engagement is increasingly being recognized as a valuable and necessary component of youth mental health research, though literature on practical strategies for implementing youth engagement principles is still in its infancy. This article outlines youth engagement activities for a multi-component intervention, specifically an integrated care...

Background: Depression is a common condition among adolescents, with rates continuing to rise. A gap exists between evidence-based recommendations for the treatment of depression and clinical practice. Integrated Care Pathways (ICPs) can help address this gap, but to date no study has examined how young people and their caregivers experience ICPs...

Background: Mental health problems are elevated in autistic individuals but there is limited evidence on the developmental course of problems across childhood. We compare the level and growth of anxious-depressed, behavioral and attention problems in an autistic and typically developing (TD) cohort. Methods: Latent growth curve models were appli...

Background Adolescents with depression often experience relationship problems with their caregivers, which predict poorer treatment outcomes. Personalising interventions by targeting factors associated with poor treatment outcomes may enhance the effectiveness of interventions. We report the development and initial evaluation of an intervention des...

Researchers increasingly employ longitudinal trajectory methods to understand developmental pathways of people on the autism spectrum across the lifespan. By assessing developmental or health-related outcome domains at three or more timepoints, trajectory studies can characterize their shape and varying rates of change over time. The purpose of thi...

Evidence-based information is essential for effective mental health care, yet the extent and accessibility of the scientific literature are critical barriers for professionals and policymakers. To map the necessities and make validated resources accessible, we undertook a systematic review of scientific evidence on child and adolescent mental healt...

Background Evidence-based policymaking is needed so that health systems can address the gap in care for children and adolescents facing mental health challenges. We describe the development of an open-resource dataset providing a comprehensive assessment of the needs for child and adolescent mental health care in Greece. Methods This study is a pa...

Parenting can protect against the development of, or increase risk for, child psychopathology; however, it is unclear if parenting is related to psychopathology symptoms in a specific domain, or to broad liability for psychopathology. Parenting differs between and within families, and both overall family-level parenting and the child-specific paren...

Introduction: Poor quality T1-weighted brain scans systematically affect the calculation of brain measures. Removing the influence of such scans requires identifying and excluding scans with noise and artefacts through a quality control (QC) procedure. While QC is critical for brain imaging analyses, it is not yet clear whether different QC approa...

Introduction: This secondary analysis of data collected in a randomized controlled trial (RCT) for the treatment of depression in adolescents aimed to test prediction models relating antidepressant (AD) initiation to clinical variables. Methods: The primary study was an RCT where adolescents (ages 11-17) with depression were assigned one of three o...

Background Autism is not always considered for girls and women until later along their clinical diagnostic pathways. Misdiagnosis or late diagnosis can pose significant disadvantages with respect to accessing timely health and autism-related services and supports. Understanding what contributes to roadblocks and detours along clinical pathways to a...

Digital media screens have become an essential part of our family life. However, we have insufficient knowledge about parental screen use patterns and how these affect children's socio‐emotional development. 867 Canadian parents of 5‐year old children from the TARGet Kids! Cohort (73.1% mothers, mean age=38.88±4.45 years) participated from 2014 to...

Screening for emotional, behavioral, and developmental disorders is generally considered to be a valuable activity in the child and youth developmental and mental health service sectors. The premise is that screening allows for early identification, which in turn allows for early intervention, which in turn leads to better long-term outcomes. While...

What people do or engage in in their daily lives, or daily life participation, is often linked to their state of being happy and healthy, as well as potential for living independently. To date, little research has been conducted on daily activity participation by autistic youth at home, at school or in the community. Learning more about individual...

Pediatric anxiety disorders (AD) are prevalent disorders with an impact on all aspects of a child's life and functioning.1 Although evidence supports commonly used treatments, there are notable concerns with the research to date.2 Heterogeneity in outcome selection, measurement, analysis, and reporting is a contributing factor to the hinderance of...

In the general population, irritability is associated with later depression. Despite irritability being more prevalent in autistic children, the long-term sequelae are not well explored. We tested whether irritability in early childhood predicted depression symptoms in autistic adolescents, and whether associations could be explained by difficultie...

Background Children with autism spectrum disorder (ASD) receive a wide range of services. Aims To examine the association between behavioural services received by children with ASD between ages 2 and 5 years and outcomes during primary school years. Methods A total of 414 preschool-aged children diagnosed with ASD were enrolled at five Canadian s...

Background Heterogeneity in adaptive behavior abilities among people with autism spectrum disorder (ASD) is expressed not only as uneven levels of impairment across domains, but also in the developmental trajectories of adaptive skills. We studied the question of whether, after accounting for global adaptive behavior development, we find evidence o...

Importance Complete information in a trial protocol regarding study outcomes is crucial for obtaining regulatory approvals, ensuring standardized trial conduct, reducing research waste, and providing transparency of methods to facilitate trial replication, critical appraisal, accurate reporting and interpretation of trial results, and knowledge syn...

Importance Clinicians, patients, and policy makers rely on published results from clinical trials to help make evidence-informed decisions. To critically evaluate and use trial results, readers require complete and transparent information regarding what was planned, done, and found. Specific and harmonized guidance as to what outcome-specific infor...

To make decisions in mental health care, service users, clinicians, and administrators need to make sense of research findings. Unfortunately, study results are often presented as raw questionnaire scores at different time points and regression coefficients, which are difficult to interpret with regards to their clinical meaning. Other commonly rep...

Background Behavioral symptom trajectories are informative of the development of young children at increased likelihood for autism spectrum disorder (ASD). Methods Developmental trajectories of early signs were examined in a cohort of siblings of children diagnosed with ASD (n = 502) from 6 to 18 months using the Autism Observation Scale for Infan...

There is a need for reliable and valid screening tools that assess depressive symptoms in adolescents in Pakistan. To address this need, the present study examined the psychometric properties and factor structure of a Sindhi-translated and adapted version of the child-report Mood and Feelings Questionnaire (MFQ-C) and the Short Mood and Feelings Qu...

Background. Adolescents with depression often experience relationship problems with their caregivers, which predict poorer treatment outcomes. Personalizing interventions by targeting factors associated with poor treatment outcomes may enhance the effectiveness of interventions. We report the development and initial evaluation of an intervention de...

Parenting can protect against the development of, or increase risk for, child psychopathology; however, it is unclear if parenting is related to psychopathology symptoms in a specific domain, or to broad liability for psychopathology. Parenting differs between and within families, and both overall family-level parenting and the specific parenting a...

Background: Intensive longitudinal data collection, including ecological momentary assessment (EMA), has the potential to reduce recall biases and increase our understanding of dynamic associations between variables. Cost and privacy concerns represent barriers that may limit the use of EMA. Research Electronic Data Capture (REDCap), a freely avail...

Fully understanding autism spectrum disorder (ASD) genetics requires whole-genome sequencing (WGS). We present the latest release of the Autism Speaks MSSNG resource, which includes WGS data from 5,100 individuals with ASD and 6,212 non-ASD parents and siblings (total n = 11,312). Examining a wide variety of genetic variants in MSSNG and the Simons...

This study examined educators’ descriptions of the positive character traits of students with autism spectrum disorder at ages 7–8 and 10–11, using an adapted version of the Values in Action (VIA) Classification of Strengths. The most commonly endorsed strengths at both age intervals were kindness, specific skills, self-regulation, and perseverance...

Background Evidence-based information is essential to delivering effective mental health care, yet the extent and accessibility of the scientific literature are critical barriers for professionals and policymakers. To map the necessities and make validated resources accessible, we undertook a comprehensive analysis of scientific evidence on child a...

We examined the narrative abilities of bilingual and monolingual children on the autism spectrum (AS), whether bilinguals presented stronger social and pragmatic language abilities compared to monolinguals, and the link between narrative, social, and pragmatic language abilities. The narrative, social, and pragmatic language skills of school-aged b...

Adolescent mental health (MH) disorders with striking prominence include anxiety, self-harm and depression. The current review aims to highlight high-quality reviews of novel interventions, mainly Cochrane reviews, and/or quality meta-analyses published between 2019 and 2022 on three adolescent mental health challenges. Recent evidence about the ef...

The canonical paradigm for converting genetic association to mechanism involves iteratively mapping individual associations to the proximal genes through which they act. In contrast, in the present study we demonstrate the feasibility of extracting biological insights from a very large region of the genome and leverage this strategy to study the ge...

Unlike best practice guidelines for detecting and addressing medication side effects, there are no widely adopted guidelines to help therapists identify and address the possible negative effects of psychotherapy. Psychotherapy is a first-line evidence-based intervention for youth depression and anxiety, but the literature contains few studies of ps...

Importance: Understanding the longitudinal, bidirectional associations between disturbed sleep and depression in childhood and adolescence is crucial for the development of prevention and intervention programs. Objective: To test for bidirectional associations and cascade processes between disturbed sleep and depressive symptoms covering both ch...

Objectives Youth face numerous challenges in receiving coordinated and continuous mental health services, particularly as they reach the age of transition from child and adolescent mental health services (CAMHS) to adult mental health services (AMHS). The Longitudinal Youth in Transition Study (LYiTS) follows youth prospectively as they cross this...

Self-report measures are central in capturing young people’s perspectives on mental health concerns and treatment outcomes. For children and adolescents to complete such measures meaningfully and independently, the reading difficulty must match their reading ability. Prior research suggests a frequent mismatch for mental health symptom measures. Si...

Transactional models employing cross-lagged panels have been used for over 40 years to examine the longitudinal relations and directional associations between variables of interest to child and adolescent mental health. Through a narrative synthesis of the literature, we provide an accessible overview of cross-lagged panels with attention to develo...

Autistic children experience high rates of anxiety. Insistence on sameness behaviour (IS) is a core feature of autism that appears correlated with anxiety severity. The objective of this study was to examine the longitudinal relations between anxiety and IS in autistic children using a developmental cascade model. A longitudinal cohort of 421 autis...

Background Externalizing and internalizing behaviors contribute to clinical impairment in children with neurodevelopmental disorders (NDDs). Although associations between externalizing or internalizing behaviors and cortico-amygdalar connectivity have been found in clinical and non-clinical pediatric samples, no previous study has examined whether...

Suicidality is increased in autism spectrum disorder (ASD), yet effective interventions are lacking. Developing biologically based approaches for preventing and treating suicidality in ASD hinges on the identification of biomarkers of suicidal ideation (SI). Here, we assessed magnetic resonance spectroscopy (MRS) markers of glutamatergic neurotrans...

Background Youth mental health appears to have been negatively impacted by the COVID-19 pandemic. The impact on substance use is less clear, as is the impact on subgroups of youth, including those with pre-existing mental health or substance use challenges. Objective This hypothesis-generating study examines the longitudinal evolution of youth men...

Fully understanding the genetic factors involved in Autism Spectrum Disorder (ASD) requires whole-genome sequencing (WGS), which theoretically allows the detection of all types of genetic variants. With the aim of generating an unprecedented resource for resolving the genomic architecture underlying ASD, we analyzed genome sequences and phenotypic...

Lay abstract: Sibling relationship quality is important for the well-being of children on the autism spectrum and their siblings. Little is known, however, about how varied behavior and abilities of children on the autism spectrum may be associated with parent perceptions of domains of sibling relationship quality. We drew data from a subsample of...

Background: To co-ordinate a multidisciplinary team in the delivery of guideline recommendations using a measurement-based care framework, our group previously developed a care pathway for the treatment of depression in adolescents. Core components of the pathway were: assessment, education, cognitive-behavioural therapy, a caregiver intervention...

Over the past decade, visits to American and Canadian emergency departments (EDs) for child and youth mental health care have increased substantially.1,2 Acute mental health crises can occur as a result of a variety of concerns, including those that are life threatening (eg, suicide attempts), pose safety concerns (eg, suicidal intentions, aggressi...

Introduction An important consideration for determining the severity of mental health symptoms is their impact on youth’s daily lives. Those wishing to assess ‘life impact’ face several challenges: First, various measurement instruments are available, including of global functioning, health-related quality of life and well-being. Existing reviews h...

Introduction: Depressive disorders in adolescents are common and impairing. Evidence-based treatments are available; however, at a cost. In the context of the pandemic, we anticipate increased demand for treatment services for adolescents with depression. We also anticipate that economic resources will be strained. Identifying cost-effective strate...

Background Autism Spectrum Disorder (ASD) and Attention Deficit Hyperactivity Disorder (ADHD) have considerable overlap, supporting the need for a dimensional framework that examines neurodevelopmental domains which cross traditional diagnostic boundaries. In the following study, we use factor analysis to deconstruct the ASD–ADHD phenotype into its...

Importance: The application of precision medicine principles for the treatment of depressive disorders in adolescents requires an examination of the variables associated with depression outcomes in randomized clinical trials (RCTs). Objective: To describe predictors, moderators, and mediators associated with outcomes in RCTs for the treatment of...

Background Language regression, broadly defined as the loss of acquired language skills in early childhood, is a distinctive feature of autism. Little is known about the factors underlying regression or the prognosis of children who exhibit regression. We examine potential predictors of language regression and test its association with language dev...

Sex and gender are dissociable, multi-component variables. Focusing on the analytic problems associated with dichotomising continuous variables, we synthesize a new approach to collecting and analysing sex and gender data in health research, in contrast to the conventional use of dichotomous tickboxes to code sex/gender.Methods. Using a literature...

Background: Pediatric cancer diagnosis and treatment can have detrimental mental health effects on parents (caregivers) and their children/adolescents (youth). Psychosocial screening and intervention have been recognized as standards of care in pediatric oncology. The most effective psychosocial interventions to support those in need post screenin...

Lay abstract: Experiencing stressful life events, such as a parent having had serious illness, parental divorce, bullying and victimization, is known to increase risk for mental health difficulties in neurotypical children. However, few studies have looked at whether stressful life events have a similar impact in autistic youth and if any individu...

Background: Many phenotypic studies have estimated the degree of comorbidity between Autism Spectrum Disorder (ASD) and Attention Deficit Hyperactivity Disorder (ADHD), but few have examined the latent, or unobserved, structure of combined ASD and ADHD symptoms. This is an important perquisite toward better understanding the overlap between ASD and...

Background: Digital media screens have become an essential part of our family life. While most studies focus on children’s screen use, we know less about parental screen use patterns and how these affect children’s socio-emotional development.Method: 867 Canadian parents of 5-year old children from the TARGet Kids! Cohort (73.1% mothers, mean age=3...

This study examined parental perceptions of the character traits of children with autism from early childhood to age 11. Parents (n = 153) provided descriptions of the “best things” about their children on the Child Behavior Checklist (CBCL) at ages 3–4, 7–8, and 10–11 years. Descriptions were coded using the framework of the Values in Action Class...

Autism Spectrum Disorder (ASD) is genetically complex with ~100 copy number variants and genes involved. To try to establish more definitive genotype and phenotype correlations in ASD, we searched genome sequence data, and the literature, for recurrent predicted damaging sequence-level variants affecting single genes. We identified 18 individuals f...

Background Genomic loci where recurrent pathogenic CNVs are associated with psychiatric phenotypes in the population may also be sensitive to the collective impact of multiple functional low-frequency single nucleotide variants (SNVs). Methods We examined the cumulative impact of low-frequency functional SNVs within the 22q11.2 region on schizophr...

Background Current first-line treatments for paediatric depression demonstrate mild-to-moderate effectiveness. This has spurred a growing body of literature on lifestyle recommendations pertaining to nutrition, sleep and exercise for treating paediatric depression. Aims Paediatric depression clinical practice guidelines (CPGs) were reviewed for qu...

Background There are growing calls to engage service users in research about issues relevant to them. Youth and family members can make meaningful contributions to research projects, improving quality and relevance. However, more information is needed on the contributions that youth and family members can make to various study designs. Objective T...

Introduction Longitudinal trajectory methods, featuring outcome assessments at three or more time points, are increasingly being used as appropriate approaches to understand developmental pathways of people on the autism spectrum across the lifespan. Understanding the scope of this rapidly expanding body of research can help inform future trajector...

Objective Psychosocial screening is a standard of care in pediatric oncology, but there is limited information about how to intervene after screening. This pilot trial aimed to determine feasibility of the novel Enhanced Psychosocial Screening Intervention (EPSI) and explore its preliminary efficacy outcomes. We examined rates of recruitment, reten...

Altered excitatory and inhibitory neurotransmission has been implicated in autism spectrum disorder (ASD). Interventions using repetitive transcranial magnetic stimulation (rTMS) to enhance or inhibit cortical excitability are under study for various targets, though the mechanistic effects of rTMS have yet to be examined in ASD. Here, we examined w...

Many neurodevelopmental disorders (NDDs) share common learning and behavioural impairments, as well as features such as dysregulation of the oxytocin hormone. Here, we examined DNA methylation (DNAm) in the 1st intron of the oxytocin receptor gene, OXTR, in patients with autism spectrum (ASD), attention deficit and hyperactivity (ADHD) and obsessiv...