Across Europe, adolescent mental health services are under unprecedented pressure. While contact with nature is widely recognised as beneficial for mental wellbeing, existing research does not consider adolescents who are already on a psychiatric path. Forest4Youth responds to this overlooked gap, investigating how real forests — and, where access is limited, immersive virtual nature — can be integrated into evidence-based mental health pathways for young people during and after hospitalisation.

Led by the Centre Neuropsychiatrique Saint-Martin (CNP) in Belgium and funded through Interreg North-West Europe, Forest4Youth brings together psychiatric hospitals, universities, forest managers, and technology experts. The project focuses on adolescents aged 12 to 18 who are hospitalised or recently discharged following a mental health crisis. Within the consortium, The Royal College of Surgeons In Ireland (RCSI) and Free University of Brussels (ULB) are leading the research activities.

"Much of the research on nature and mental health focuses either on adults or on healthy populations," explains Kate Brassington, PhD researcher at RCSI. "There is surprisingly little evidence when it comes to adolescents who are already in psychiatric care — particularly those transitioning back to everyday life after hospitalisation."

Adolescence is increasingly recognised as a distinct developmental stage, marked by heightened vulnerability but also significant potential for recovery. Diagnostic categories can take months or years to establish, and young people are frequently admitted based on acute symptoms rather than formal diagnoses.

At CNP Saint-Martin, adolescents are hospitalised during moments of crisis, when outpatient care is no longer sufficient. "They arrive because something in their life has become a danger, either for themselves or for their family environment," explains Vinciane de Moffarts, the project manager. "Many arrive without a diagnosis, but with severe anxiety, suicidal thoughts, or a sense of complete emptiness."

Clinicians have observed a marked shift since COVID-19. "Before, adolescents in crisis were often seen as troublemakers. Now, many are not making trouble at all. They are withdrawn, disconnected, and struggling to find purpose or perspective."

The idea that nature supports mental wellbeing is not new — studies from Japan, South Korea and China have long explored shinrin-yoku or "forest bathing". What remains unclear is how these benefits translate into structured therapeutic interventions for vulnerable adolescents.

"What we know is that being in a forest is generally good for you. What we don't yet understand is why, for whom, and under what conditions it works best." — Brassington

Existing studies vary widely; some interventions last just 12 minutes, others involve multi-day stays. Outcomes are typically measured immediately before and after a single visit, with very few longitudinal follow-ups. Forest4Youth aims to move beyond whether forests are beneficial, and instead investigate how they can be meaningfully integrated into care pathways — examining group vs. individual activities, guided vs. unstructured experiences, and the role of sensory engagement, autonomy, and perceived safety.

Rather than a one-size-fits-all model, Forest4Youth is developing a flexible forest-based care protocol adaptable to different clinical settings, forest types and cultural contexts. This protocol is being co-created through a participatory research process involving adolescents, families, mental health professionals and forest managers.

Access to forests remains uneven. Transport, mobility issues, safety concerns and staffing constraints all create barriers — particularly for adolescents in hospital or urban settings. This is where Forest4Youth introduces its second strand: immersive virtual reality (VR).

"We are not trying to replace real forests," emphasises Prof. Malgorzata Klass (ULB), lead for VR research. "VR is a complementary tool, designed for situations where access to nature is limited or temporarily impossible."

Unlike headset-based VR, Forest4Youth employs an immersive VR room, where forest environments are projected onto all four walls. Participants can see their own bodies, interact with others, and move freely — creating a shared, embodied experience rather than an isolated one.

"This setup allows group interaction and collaboration. It also avoids some of the discomfort and disorientation associated with head-mounted displays, which is especially important for adolescents with mental health vulnerabilities." — Klass

"Most existing VR studies involve healthy university students," says Mostafa El Madani, PhD researcher at ULB. "Clinical populations and adolescents are largely absent."

Forest4Youth will explore how immersive virtual nature can support emotional regulation, stress reduction and preparation for real-world forest experiences. VR may be used before forest visits to familiarise adolescents with the environment, or afterwards to support reflection and reintegration.

Psychological questionnaires remain the most common tools, alongside physiological indicators such as heart rate variability or cortisol levels — yet no single biomarker reliably captures mental wellbeing in adolescents.

"There is no textbook that tells you the right measure for forest-based mental health. That uncertainty is part of the field and part of what makes this research necessary." — Klass

Forest4Youth will use a mixed-methods approach combining quantitative measures with interviews and longer-term follow-ups, aiming to contribute robust evidence to a field currently dominated by short-term studies.

In the project's later stages, partners plan to engage directly with public authorities to advocate for the recognition of green care within mental health systems.

"Research often takes 10 to 15 years to influence practice. Here, we are involving policymakers, clinicians and service users from the start." — de Moffarts

If successful, Forest4Youth could help reframe forests not only as recreational or environmental assets, but as integral components of public health infrastructure.

"Yes, we're doing careful, complex research, but at the same time, there's a simple message. Nature matters: and for many adolescents, it may be one of the most powerful places to begin healing." — Brassington