# Nature-Based Health Interventions for People with Mild to Moderate Anxiety, Depression, and/or Stress: Identifying Target Groups, Professionals, Mechanisms, and Outcomes Through a Delphi Study

## TL;DR

This study identifies key components for nature-based health interventions to support people with mild to moderate anxiety, depression, or stress.

## Contribution

The study provides a systematic framework for designing nature-based interventions using expert consensus and thematic analysis.

## Key findings

- Consensus was reached on core mechanisms like nature interaction and social community.
- Mental wellbeing and quality of life were top outcome priorities.
- Professional competencies and context adaptation are crucial for effective interventions.

## Abstract

Public health relevance—How does this work relate to a public health issue?
Mild to moderate anxiety, depression, and/or stress are widespread and impair everyday functioning and quality of life.Current treatment options do not always meet the needs of this group, increasing interest in nature-based health interventions (NBHIs) in mental-health support.

Mild to moderate anxiety, depression, and/or stress are widespread and impair everyday functioning and quality of life.

Current treatment options do not always meet the needs of this group, increasing interest in nature-based health interventions (NBHIs) in mental-health support.

Public health significance—Why is this work of significance to public health?
The development of effective NBHIs requires a systematic, population-specific framework.This study identifies key elements; target group specifics, professional roles, mechanisms, and outcomes, essential for designing such interventions.

The development of effective NBHIs requires a systematic, population-specific framework.

This study identifies key elements; target group specifics, professional roles, mechanisms, and outcomes, essential for designing such interventions.

Public health implications—What are the key implications or messages for practitioners, policy makers and/or researchers in public health?
NBHIs should be approached as complex interventions within a bio-psycho-social health perspective.The findings offer a shared foundation for practitioners, policy makers, and researchers to design and evaluate context-sensitive NBHIs.

NBHIs should be approached as complex interventions within a bio-psycho-social health perspective.

The findings offer a shared foundation for practitioners, policy makers, and researchers to design and evaluate context-sensitive NBHIs.

Nature-based health interventions (NBHIs) are increasingly used in the healthcare system to support people with anxiety, depression and/or stress, highlighting the need for systematic development and evaluation. This study aims to identify target group, professionals, mechanisms, and outcomes of NBHIs for people with mild to moderate anxiety, depression, and/or stress. A Delphi-based study was conducted to explore core components of NBHIs in healthcare settings. Thirteen vs. eleven researchers with expertise related to the target group responded in two rounds. Respondents rated statements on a 7-point Likert scale and prioritised core components regarding target group, professionals, mechanisms, and outcomes. A thematic analysis was applied to synthesise qualitative responses. Consensus was achieved on 12 of 21 items across the four domains. Highest agreement concerned core mechanisms (nature interaction, social community, and physical activity), outcome priorities (mental wellbeing and quality of life), and professional competencies. Greater variation was observed regarding group composition and team delivery. Analysis of qualitative expert responses highlighted four key themes: (1) Balancing Group Composition, (2) Adapting Competencies to Context, (3) Core Mechanisms for Change, and (4) Weighing Perspectives in Outcome Selection. By setting out guiding principles for a programme theory, the study lays the foundation for the design and implementation of context-adapted NBHIs. The study underscores the need to approach NBHIs as complex interventions, thus contributing to a paradigm shift towards a new era of a bio-psycho-social health perspective.