YOUth Adolescent cohort framework protocol

Childhood (including puberty) is characterized by rapid and profound changes in
the brain accompanied by biological and psychological change; consequently,
this is a critical period for the development of behavioral, psychological and
psychiatric problems. Indeed, across child development, psychiatric disorders
are the most important cause of burden of disease in high-income countries. For
instance, 23% of all disability-adjusted life years (DALYs) in children between
0-14 years old are attributable to psychiatric disorders. Moreover, children
without psychiatric disorders also often experience behavioral problems that
are equally disruptive, at a personal, familial and societal level. This makes
it crucial to grasp how such behavioral changes arise, and to what extent these
changes are related to changes in brain development. However, despite the
obvious relevance of relating brain development to behavioral development,
there is a paucity of longitudinal studies examining structure and function,
including cognition, of the brain in childhood. There is also little insight
into how biological, child-related and environmental factors interact in
shaping brain and behavior during the course of development.

The YOUth cohort focuses on neurocognitive development (brain and cognitive
development) involved in two core characteristics of behavioral development:
social competence and behavioral control. From an early age, deficiencies in
social competence and behavioral control have been linked to a variety of
behavioral, psychological and psychiatric disorders. For our studies we will
use a longitudinal cohort design, since the (limited) research explaining
variation in child and adolescent problematic behaviors has mostly been
conducted in cross-sectional and case-control studies. A longitudinal cohort
design is better suited to study the effect of biological, child-related and
environmental characteristics on the developing brain (neurocognitive
development) and subsequently on the developing behavior. We will cover the
whole range of variation in behavioral development, ranging from uncomplicated
development, through problem behavior, to psychiatric disorders.

A primary motivation of the proposed research in this framework protocol is not
only to advance scientific knowledge about developing brains and behaviors, but
also to inform on policy-level questions. Key features of the proposed research
program have implications for strategies to help identify individual genetic or
acquired susceptibility, and optimal developmental timing for preventive
efforts. Thereby, it will provide approaches to identify high-risk individuals
in combination with high-risk social environments, and create opportunities for
influencing these psychosocial sensitivities in positive ways; that is, by
offering crucial advice for taking care of vulnerable youth.

This cohort study aims to explain why some children develop well and others
fail to thrive in society. To this purpose, we examine how neurocognitive
development mediates the association between developmental changes in
biological, child-related and environmental factors, and specific behavioral
development and general functioning in children.

A prospective population-based longitudinal cohort study in the general
population with repeated measurements every three years.

For the parents, the burden associated with participation consists of: a range
of questionnaires (approximately 80-120 minutes every three years), blood and
buccal cell donations (at baseline only) and an IQ test (at baseline only).
For the children, the burden associated with participation consists of: MRI,
behavioral and cognitive tests, blood, saliva and buccal cell donation and
questionnaires (approximately 100-120 minutes; each three-year-wave).
There are minimal risks associated with each of these subparts.
The YOUth cohort aims to investigate how the interplay of biological,
child-related and environmental developmental changes affects brain and
behavioral development in children. The nature of our research questions makes
it immediately clear that our research can only be performed in children.