Genetics in child and adolescent psychiatry: methodological advances and conceptual issues

Papa was a rollin' stone: how father's psychological distress impacts child's internalizing and externalizing symptoms

While parental psychological distress is a commonly examined risk factor in the development and maintenance of child's emotional and behavioral problems, there is an incomplete understanding of the unique contribution of the father. The current study examines whether paternal psychological distress (i.e., depression, anxiety, and anger) exacerbates child's internalizing and externalizing behaviors, as well as whether a child's internalizing and externalizing behaviors exacerbate paternal psychological distress. The National Institute of Child and Human Development (NICHD)'s Study of Early Child Care and Youth Development (SECCYD) longitudinal dataset was utilized. A bivariate latent difference score model was applied to examine the interdependence of each member within the dyad. This novel statistical technique allowed for the examination of the influence of psychological distress in the father-child dyad across 10 years. Results indicated that paternal anger is a risk factor associated with the development and maintenance of internalizing and externalizing behaviors in children. Likewise, children's behavioral problems served as a contributing factor to paternal anger and anxiety. Results were nonsignificant for the effect of depression on change in internalizing and externalizing problems. The initial levels correlated with each other, but one did not affect the change in the other. Overall, the results have clinical implications, as they can be applied to the creation or modification of intervention plans by shifting the focus from the primary outcome being a decrease in child problem behavior to an overall reduction of psychological distress in the family unit.

All for one and one for all: heterogeneity of genetic etiologies in neurodevelopmental psychiatric disorders

Alexandre Dumas' famous phrase All for One and One for All recapitulates our current understanding of the genomic architecture of neurodevelopmental psychiatric disorders (NPD), like autism Spectrum disorder, bipolar disorder, and schizophrenia. Many rare genomic variants of large effect size have been identified; all of them together can explain a significant proportion of NPD. In parallel, one rare genomic variant can cause all of the above NPD. Finally, common genomic variants of individually small effect size can be combined to further explain risk for NPD. How do we reconcile different genomic variants accounting for one clinical diagnosis, and different clinical diagnoses arising from a single genomic variant? Here, we discuss a framework to understand genetic and clinical heterogeneity in NPD.

Twenty years of research on attention-deficit/hyperactivity disorder (ADHD): looking back, looking forward

In this clinical review we summarise what in our view have been some the most important advances in the past two decades, in terms of diagnostic definition, epidemiology, genetics and environmental causes, neuroimaging/cognition and treatment of attention-deficit/hyperactivity disorder (ADHD), including: (1) the most recent changes to the diagnostic criteria in the Diagnostic and Statistical Manual of Mental Disorders and International Classification of Diseases; (2) meta-analytic evidence showing that, after accounting for diagnostic methods, the rates of ADHD are fairly consistent across Western countries; (3) the recent finding of the first genome-wide significant risk loci for ADHD; (4) the paradigm shift in the pathophysiological conceptualisation of ADHD from alterations in individual brain regions to a complex dysfunction in brain networks; (5) evidence supporting the short-term efficacy of ADHD pharmacological treatments, with a different profile of efficacy and tolerability in children/adolescents versus adults; (6) a series of meta-analyses showing that, while non-pharmacological treatment may not be effective to target ADHD core symptoms, some of them effectively address ADHD-related impairments (such as oppositional behaviours for parent training and working memory deficits for cognitive training). We also discuss key priorities for future research in each of these areas of investigation. Overall, while many research questions have been answered, many others need to be addressed. Strengthening multidisciplinary collaborations, relying on large data sets in the spirit of Open Science and supporting research in less advantaged countries will be key to face the challenges ahead.

A Theory of Mental Health and Optimal Service Delivery for Homeless Children

Homeless children are a vulnerable group with high risk for developing mental health disorders. The pathways to disorders among homeless children have not been fully elucidated, with significant logistical and measurement issues challenging accurate and thorough assessment of need. The environments of homeless children are uniquely chaotic, marked by frequent moves, family structure changes, household and neighborhood disorder, parenting distress, and lack of continuous services. Despite high rates of service use, mental health outcomes remain poor. This paper reviews the literature on homeless children's mental health, as well as prior theoretical explorations. Finally, the paper proposes a theoretical model that explains elevated rates of mental health problems among homeless children as consequences of harmful stress reactions triggered by chronic household instability along with repeated service disruptions. This model draws upon existing conceptual frameworks of child development, family poverty, health services utilization, and the biology of stress to clarify the role of environmental chaos in the development of child emotional and behavioral problems. Potential strategies to mitigate the risk for mental health disorders among homeless children and future research directions are discussed.