Greenspace interventions for mental health in clinical and non-clinical populations: What works, for whom, and in what circumstances?

The interaction of nature, individual changes, and social changes are linked to desired outcomes for greenspace mental health interventionsInterest in greenspace interventions for mental health is a rapidly-growing phenomenon internationally. While research supports the effectiveness of greenspace interventions for people of different ages, little is known about the underlying mechanisms and processes contributing to their success. This review addressed this gap by synthesizing the evidence for greenspace interventions for populations with a mental health diagnosis or having self-diagnosed mental health concerns.

Forty-nine studies were included in this review. For each study, details relating to contexts, mechanisms, and outcomes of greenspace interventions were identified and recorded. Twenty-seven of the included studies found that the interaction of nature, individual changes, and social changes were linked to best mental health outcomes, regardless of program type (e.g., wilderness adventures, horticultural therapy, care farms, etc.). The desired outcomes include decreased stress, anxiety, and mental fatigue and increased physical activity, confidence, self-esteem, and willingness to make change. Some of the mechanisms related to the desired outcomes include time for reflection, planned structured activities, learning new skills, and opportunities to share.

Further synthesis of the data led to the development of seven program theories relating to the three identified themes (Nature, Individual Self, Social Self). Nature-related theories focused on “escape/getting away” and “space to reflect.” Theories related to Individual Self included “Physical Activity,” “Self-efficacy,” and “Purpose.” Theories relating to Social Self included “Relationship with Facilitator” and “Shared Experiences.” These seven theories focused on “what works” for greenspace mental health interventions. Analysis of the data also revealed some barriers to success or areas of concern, including age-related differences, limited time and resources, and issues relating to professional training and competence.

The seven theories developed around the themes of Nature, Individual Self, and Social Self provide some understandings about how greenspace mental health interventions work for different populations. These understandings have practical relevance in the design and implementation of such interventions. Of special note is the need for programs to “include adequate opportunities for development in both individual and social skills.”