Brain imaging and genetic data alone

Brain imaging (and genetic) data alone are insufficient for tracking trajectories in Digoxigenin-11-UTP development. A significant time commitment must be made to the assessment of cognition and mental health. In the Saguenay Youth Study, for example, we have spent ∼8 h of the participant\'s time in these domains. Given a large variety of approaches and available tools, only broad recommendations can be made. When assessing cognition, we have used a combination of standardized (e.g., WISC-III) and computer-based (e.g., auditory processing) tools combined in two 3-h sessions (adolescents). In adults, we have decided to use a 1-h (standardized) battery of cognitive tests. In the mental-health domain, we have focused on self-reported symptoms rather than using a diagnosis-driven (psychiatric-interview based) approach. Conceptually, this strategy is consistent with a move away from categorical definitions of psychiatric disorders, as defined in the Diagnostic and Statistical Manual of Mental Disorders (DSM), and toward symptoms as a preferred level of analysis (Borsboom et al., 2011). From a methodological standpoint, self-reports are a rich source of reliable information, especially in the context of substance use (Sobell and Sobell, 1990). Finally, any developmental study must consider the caregivers. As illustrated in Fig. 4, parents are the main source of genetic and environmental influences on the developing brain. For this reason, we have obtained parental DNA and basic information about the mental health of the parents (including anti-social behavior during their adolescence) in Wave 1 of the Saguenay Youth Study, and have embarked on deep phenotyping of the parents in Wave 2. Parents are also a key source of information about the life events encountered by their children at different stages of development; prospective longitudinal birth cohorts, such as the Avon Longitudinal Study of Parents and Children (Boyd et al., 2013), Northern Finland Birth Cohort 1986 (Taanila et al., 2004) or Generation R (Jaddoe et al., 2010) are in an advantageous position to use such information to predict the state of brain development (and mental health) at later point in the lives of their participants.
Conclusions As pointed out in Introduction (Section 1.1), the life-span perspective on health trajectories reflects the concept of developmental cascades: transactions occurring over time, as well as across systems and organs. The Saguenay Youth Study and its parent arm attempts to integrate detailed information about brain and cardio-metabolic health acquired at the system and molecular levels in a family-based multi-generational context. We hope that the richness of the dataset will allow us to contribute toward current efforts aimed at distinguishing the key processes of healthy trajectories from those leading to common chronic disorders of the brain and body.
Conflict of interest
Acknowledgements The Saguenay Youth Study and its parent arm are funded by the Canadian Institutes of Health Research (TP, ZP), Heart and Stroke Foundation of Quebec (ZP), and the Canadian Foundation for Innovation (ZP). We thank all families who took part in the Saguenay Youth Study and the following individuals for their contributions in designing the protocol and acquiring the data in the Parent arm of the study: Dr. Solja Niemela, Prof. Juha Veijola, Dr. Vesa Kiviniemi, Dr. Rosanne Aleong, Courtney Gray, Hélène Simard, Annie Gauthier and the ECOGENE-21/CMGC staff. We thank Dr. Michel Berube for the radiological review of MR scans with incidental findings, Manon Bernard for designing and managing our online database, and Deborah Schwartz and Angelita Wong for their help with preparing the tables and reviewing the first draft of the manuscript.
Introduction Current research on psychiatric disorders has placed a strong emphasis on early detection and treatment. Many symptoms of schizophrenia, mood disorders and addiction first manifest during the adolescent period (Adriani and Laviola, 2004; Casey et al., 2008; Schramm-Sapyta et al., 2009; Mitchell and Potenza, 2014). Accordingly, it is critical to elucidate the biological and environmental risk factors that render adolescents highly vulnerable to these disorders. Such mechanistic knowledge is necessary for the development of interventions to prevent or attenuate the emergence of disease.