A Virtual Reality-Based Horticultural Planting Program for Elderly With Subthreshold Depression

A Virtual Reality-Based Horticultural Planting Program for Elderly With Subthreshold Depression：A Randomized Controlled Pilot Study

Subthreshold depression represents a state of psychological sub-health between normal individuals and clinical depression. It constitutes a high-risk stage for developing clinical depression and a critical phase for alleviating depressive symptoms. However, current research predominantly focuses on treating depression in the elderly, with insufficient attention to interventions for high-risk populations or limited to cross-sectional investigations of subthreshold depression risk factors. Therefore, prioritizing subthreshold depression in the elderly and implementing early interventions is essential. A 2024 article in The Lancet suggests that subthreshold depression treatment should prioritize psychotherapy and lifestyle adjustments over medication. Horticultural therapy, an interdisciplinary approach integrating horticulture, medicine, and psychology, demonstrates unique advantages over traditional medical treatments. In practical application, however, limited resources may hinder adequate support for horticultural activities, compromising activity quality, reducing therapeutic efficacy, and restricting the widespread adoption of horticultural therapy. Integrating VR technology with horticultural therapy can provide patients with more comprehensive, personalized, and effective mental health treatment plans, empowering them toward healthier, more positive lives. Therefore, the research team designed a VR horticultural intervention system for elderly individuals with subthreshold depression based on the Social Participation Competence Framework.

Subthreshold depression (SD) represents a state of psychological sub-health between normal individuals and clinical depression. It constitutes a high-risk stage for developing major depressive disorder and a critical window for alleviating depressive symptoms. An editorial published in JAMA emphasized that research on subthreshold depression holds significant implications for exploring the prevention and treatment of depression. Therefore, prioritizing subthreshold depression in older adults and implementing early interventions is essential. Multiple studies indicate that social engagement, as one of the modifiable factors for depression in older adults, can actively delay the onset and progression of geriatric depression. Social engagement encompasses multidimensional activities through which older adults exchange material and emotional resources and gain social recognition. These include participation in activities, fulfillment of social roles, interpersonal interactions, utilization of social resources, and the restoration of personal value. Factors such as retirement, illness, or physical decline often lead to a narrowing of older adults' existing social networks and weakened social connections. This results in reduced scope and frequency of social engagement, potentially triggering or exacerbating depressive disorders. Conversely, depressive disorders themselves, through core symptoms like low mood and diminished interest, further undermine older adults' willingness and ability to maintain relationships and actively participate in activities, creating a vicious cycle. A 2024 study published in The Lancet indicates that older adults with high levels of social engagement exhibit significantly lower depression risk compared to those with low engagement. Similarly, a 2023 Nature Aging study suggests that social participation may reduce depression by alleviating stress, inflammation, and cerebrovascular damage, thereby preserving brain health, building cognitive reserve, and mitigating depressive disorders.

Virtual Reality (VR) technology, as a novel intervention method, possesses three key characteristics: immersion, interactivity, and simulation. By replicating real-world settings such as home and community environments, it enriches the training experience for elderly individuals with depression, helping them adapt to diverse social contexts and enhancing intervention outcomes. Horticultural therapy, an interdisciplinary approach integrating horticulture, medicine, and psychology, offers relatively low treatment costs with minimal side effects. It plays a positive role in promoting physical recovery, improving emotional well-being, and enhancing social skills. Increasingly, research teams are exploring VR-generated virtual horticultural environments and horticultural activity interventions. VR technology addresses multiple limitations of traditional horticultural therapy. VR-based gardening activities overcome temporal and spatial constraints, reduce the costs and risks associated with physical gardening, and provide richer, more personalized socialized horticultural settings and activities that cater to diverse patient needs. Therefore, integrating VR technology with horticultural therapy offers patients a more comprehensive, personalized, and effective mental health treatment plan, empowering them to lead healthier, more positive lives.

Inclusion Criteria:

• Age ≥ 60 years
• Meets subthreshold depression diagnostic criteria: CES-D score ≥ 16 on the Center for Epidemiological Survey, Depression Scale (CES-D) used in epidemiological surveys (this criterion is widely adopted in comparable studies)
• No communication barriers in vision, hearing, or speech
• Informed consent

Exclusion Criteria:

• Insulin dependent diabetes
• Thyroid disease
• Recent exposure to a major traumatic stress event, with no risk of suicide
• Currently participating in other similar studies
• Clinically diagnosed with mental disorders such as depression or schizophrenia
• Currently taking antidepressant medication
• Severe cognitive impairment
• Severe physical illness or organic disorder with impaired self-care abilities