Virtual Nature Experiences as a Supplement in the Treatment of Moderate Depression

Depression is a common mental health condition that can cause low mood, lack of energy, sleep problems, and difficulties in daily functioning. Many people with mild to moderate depression do not receive sufficient treatment because of barriers such as limited access to services, stigma, or low motivation to seek help. Physical activity and contact with nature have been shown to improve mental health, and activities performed in natural environments ("green exercise") may provide additional psychological benefits compared with indoor exercise. However, people with depression may experience barriers to engaging in outdoor activities, such as low motivation, limited access to natural environments, or unfavorable weather conditions.

Virtual reality (VR) technology can simulate immersive natural environments and may provide a way to experience nature indoors. VR-mediated experiences of nature (or "virtual nature") can provide similar psychological benefits of rea-life nature experiences. Moreover, as virtual nature experiences have been found to elicit increased sense of nature connectedness and intention to perform green exercise, which may in turn support increase participation in actual green exercise. While virtual nature interventions have shown promising results in different health contexts and are considered safe and feasible, little research has examined their effects of integrating such medium within clinical standard treatments for depression.

The purpose of this study is to investigate whether virtual nature can be an effective supplement to standard treatment for patients with mild to moderate depression. Specifically, the study will evaluate whether the combination of standard treatment and virtual nature improves mood and reduces depressive symptoms compared with treatment as usual. The study will also explore whether the intervention influences participants' motivation to engage in physical activity and outdoor green exercise over time. Finally, the study will examine possible differences between two approaches to deliver virtual nature experiences to patients in treatment for depression, namely a "high-end" and laboratory-based approach vs a "low-end" and self-managed approach.

Participants will be recruited from a psychiatric outpatient clinic that treats individuals with depression and anxiety disorders. Eligible participants will be adults diagnosed with mild to moderate depression. Patients with additional diagnosis for dementia or psychotic illness or other serious somatic illness will be excluded. Participants will be randomly assigned to one of three groups: (1) a "high-end" and laboratory-based VR intervention combined with standard treatment, (2) a "low-end" and self-managed VR intervention combined with standard treatment, or (3) a control group receiving only standard treatment. The intervention will last three weeks, and participants will be assessed at baseline, immediately after the first session, after the intervention period, and at follow-up.

The study will examine several outcomes, both to test acute and longitudinal effects. Specifically, to test for acute effects of the two VR approaches, tested outcomes include affect state, feelings of nature connectedness, intention to perform green exercise and experiences with the virtual environment (such as enjoyment, immersion, and possible side effects like cyber sickness). To test the longitudinal effects, tested outcomes include mood, symptoms of depression and anxiety, and changes in physical activity and nature connectedness.

The main hypothesis is that patients who receive virtual nature in addition to their usual treatment will experience greater improvements in mood and depressive symptoms compared with patients receiving standard treatment alone. A secondary hypothesis is that exposure to virtual nature may increase participants' motivation and engagement in real-world outdoor physical activity over time. Finally, it is expected that the high-end and lab-based VR intervention will provide more positive overall effects.

This research will provide new knowledge about whether virtual nature experiences can support mental health treatment and help people with depression become more physically active and connected to nature. If effective, the intervention could offer a low-cost and accessible supplement to existing treatment approaches for depression.