Mindfulness-Based Intervention for Adolescents (Mindfulteen)

Promotion of mental health is a major concern worldwide, particularly among young population as major psychiatric diseases can have their onset during adolescence and young adulthood. During adolescence, there is growing evidence that "at-risk" states for mental disorders, as high stress reactivity for example, can be identified prior to clinical symptoms, and that early interventions can have a major impact preventing the further development of full-blown mental illness.

In the last two decades, given a growing interest for non-pharmacological approaches to improve mental and physical health, mindfulness-based interventions (MBI) have received serious attention. After the initial applications on chronic pain, stress reduction and prevention of depressive relapses, MBIs are now widely implemented among clinical and non-clinical populations.

Therefore, investigators aim to better understand the modifications of brain circuits involved in the emergence of stress related disorders and the impact of a MBI on those circuits. Hence, a translational project was designed, integrating neuroimaging, biological and clinical outcomes of stress reactivity to evaluate the impact of a MBI on adolescents.

The Mindfulteen Study is a 3-year longitudinal cohort study with a nested randomized controlled trial. The randomized controlled trial part of the study was designed to assess the clinical effect of MBI on adolescents, comparing to a control group. Therefore, after inclusion participants are electronically randomized between either early intervention group or late intervention group (i.e., waiting list or control group). Participants allocated in the late intervention group engage in MBI after the waiting period, providing data also for the longitudinal cohort part of the study and therefore increasing the data available for before and after comparison. The long-term effect of MBI will be assessed after 18 months of intervention.

Before randomization, participants are stratified according to their score on the trait questionnaire of the State Trait Anxiety Inventory (STAI) as low anxiety group (≤ 31) or high anxiety group (>31).

Assessments are performed before intervention, immediately after intervention or waiting period and in 18 months. For the late intervention group, an additional assessment is performed immediately after the intervention.

The overall objective of the Mindfulteen Study is to assess the immediate and long-term effect of an MBI on reactivity to stress and anxiety, in a non-clinical sample of young adolescents from the general population. Underlying psychological and biological changes are assessed using a multimodal brain MRI protocol, blood and hair sampling, as well as physiological measurements of stress.

The primary aim is to characterize brain functional modifications in cortico-limbic and cortico-striatal-thalamic circuits (functional MRI data) and their underlying neuroanatomical changes (analysis of structural, spectroscopy and diffusion MRI data) in adolescents exposed to MBI, comparing adolescents with high anxiety and low anxiety levels.

Secondary aims include the effects of MBI on self-reported levels of anxiety, emotion regulation strategies (clinical scores) and physiological markers of hypothalamic-pituitary-adrenal axis (hair cortisol), as well as biological markers of oxidative stress and inflammation (blood sampling).