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. Global population aging has made mental health disorders a major public health issue. The World Health Organization reports that about 7% of people aged 60 and above worldwide suffer from depression; in China, the rates are 19.05% for mild and 12.17% for moderate-to-severe depressive symptoms. Subthreshold depression (StD) is defined as having at least two depressive symptoms (e.g., anhedonia, loss of interest) for over two weeks without meeting major depressive disorder criteria. Among older adults, StD prevalence is about 18.6%, with a 12%-15.83% risk of progressing to major depression within 2-3 years. Thus, StD represents a critical window for early prevention, and timely non-pharmacological interventions are vital to reverse progression and reduce family and social care burdens. 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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
SUPPORTIVE_CARE
Masking
SINGLE
Enrollment
62
The system comprised six progressive horticultural tasks, each associated with a distinct plant: (1) Tomato Planting, (2) Corn Cultivation, (3) Strawberry Care, (4) Eggplant Harvest, (5) Rose Growing, and (6) Sunflower Expansion. All tasks followed the same eight standardized steps-land preparation, seed sowing, seedling fertilization, initial watering, secondary fertilization, secondary watering, pest removal, and harvesting-but were arranged in a clear gradient of increasing difficulty. This progression was reflected in expanding planting scales, escalating task complexity, heightened cognitive load, more refined judgment requirements, and varying demands on operational precision. Each task was performed individually by the participant using the VR headset, without any multiplayer or collaborative components, as the system was designed for personalized, self-paced intervention.
This arm of seniors maintains their daily routines and participates regularly in the nursing home's daily activities.
Nursing school of Fujian Medical university
Fujian, Fuzhou, China
Subthreshold Depression
The Center for Epidemiological Surveys Depression Scale (CES-D) was developed by Rirodiff at the National Institute of Mental Health in the United States. It is designed for screening depressive symptoms in older adults, comprising 20 items. Each question assesses one symptom, covering 20 distinct symptoms in total. The total score ranges from 0 to 60 points. A score ≤15 indicates no depressive symptoms, 16-19 suggests possible depressive symptoms, and ≥20 confirms depressive symptoms. The Cronbach's alpha coefficient for the Chinese population is 0.90. It is one of the most commonly used subthreshold depression epidemiological survey tools, with existing studies defining CES-D ≥16 as subthreshold depression. Translated with DeepL.com (free version)
Time frame: The intervention was conducted in November 2025, and the evaluation time was 0,6 weeks .
General cognitive function
The Montreal Coanitive Asessment Scale,developed by Nasreddine in 2004 to assess participants'general cognitive function, covers eight areasof cognitive assessment, including visuospatial and executive function, naming, memory, attention, speech, abstraction, delayed recall, andorientation. The Changsha version of the Montreal Cognitive Assessment Scale was used in this study, and its Cronbach's a coeficient was 0.846,retest reliability was 0.974, and investigator reliability was 0.969. The score of the Montreal Cognitive Assessment Scale ranges from 0 to 30points. The higher the score,the better the cognitive function ofthe study subjects. The iliterate group s13, the primary school group s19 and thejunior high school and above group s24 can be judged as impaired cognitive function to correct the bias caused by education level.
Time frame: The intervention was conducted in November 2025, and the evaluation time was 0,6 weeks separately.
Anxiety Condition
The self-rating anxiety scale (SAS) was designed and developed by Zung in the United States in 1971 to assess the severity of anxiety symptoms in individuals. It demonstrates good reliability and validity, with a split-half reliability coefficient of 0.696, test-retest reliability of 0.777, and internal consistency of 0.82. Additionally, it exhibits good construct validity . The scale comprises 20 items, with items 5, 9, 13, 17, and 19 scored in reverse. The scale employs a 1-4 rating scale (1 = never or rarely; 2 = a small portion of the time; 3 = a considerable portion of the time; 4 = most or all of the time). Individuals complete the scale based on their experiences during the past week. The total score is multiplied by 1.25, rounded to the nearest whole number to obtain a standardized score, which serves as the statistical indicator. A higher standardized score indicates more severe anxiety levels
Time frame: The intervention was conducted in November 2025, and the evaluation time was 0,6 weeks separately
Self-Efficacy
The General Self-Efficacy Scale (GSES), developed by Schwarzer et al , was used. It consists of 10 items rated on a 4-point Likert scale, ranging from 1 (strongly disagree) to 4 (strongly agree). Higher total scores indicate higher levels of self-efficacy. In this study, the Cronbach α coefficient was 0.81.
Time frame: The intervention was conducted in November 2025, and the evaluation time was 0,6 weeks separately.
Sleep Quality
This study employed the Pittsburgh Sleep Quality Index (PSQI) developed by Buysse et al. in 1989 to assess patients' sleep quality over the preceding month. The 19-item questionnaire comprises seven components: subjective sleep quality, sleep onset latency, sleep duration, sleep efficiency, sleep disturbances, hypnotic medication use, and daytime functioning. The total score ranges from 0 to 21, with higher scores indicating poorer sleep quality. The Cronbach's alpha coefficient for this scale is 0.85.
Time frame: The intervention was conducted in November 2025, and the evaluation time was 0,6 weeks separately.
System Usability
System Usability Scale (SUS) Developed by Brooke et al., the scale used in this study is the Chinese version of the System Usability Scale translated and revised by Chinese scholars including Li Yongfeng. This scale is unidimensional and consists of 10 items. It employs a 5-point Likert scale, with scores ranging from 1 ("Strongly Disagree") to 5 ("Strongly Agree"). Positive items (Items 1, 3, 5, 7, 9) are scored positively: Actual item score = Item rating - 1. Negative items (Items 2, 4, 6, 8, 10) are scored negatively: Actual item score = 5 - Item rating. If an item is left blank, it is assigned a score of 3. The total scale score = sum of all item scores × 2.5. The scale has a maximum score of 100 points, with scores \>60 considered usable, 70 considered good, ≥80 considered excellent, and ≥90 considered outstanding. The Cronbach's alpha coefficient for this scale is 0.91.
Time frame: The intervention will be implemented in November 2025, with the evaluation conducted after the 6-week intervention period concludes.
Simulator Sickness
The Simulator Sickness Questionnaire(SSQ) developed by Kennedy et al. in 1993, is a widely used tool for assessing the subjective severity of simulator sickness symptoms. The SSQ consists of pre- and post-experiment sections. The pre-experiment section employs the Pensacola Motion Sickness Questionnaire (MSQ) to gather information about participants' current physical condition and prior simulator experience. The post-experiment section measures symptom severity on a four-point scale (0-3) for each symptom. SSQ items can be grouped into three factors: nausea (e.g., sweating, difficulty concentrating, gastric awareness), eye movement disturbances (e.g., headache, eye fatigue, blurred vision), and disorientation (e.g., head fullness, dizziness with eyes open/closed, vertigo). The SSQ can be scored in two ways: (1) Calculate the score for each factor by summing the scores of all relevant items (each factor includes 7 items), with a score range of 0-179.5
Time frame: The intervention will be implemented in November 2025, with the evaluation conducted after the 6-week intervention period concludes.
Immersion Presence
The Immersion Presence Questionnaire (IPQ) was employed to evaluate users' sense of immersion in the experience. Developed by Schubert et al., this questionnaire was subsequently translated into Chinese and validated for reliability and validity by Liang Jiahui et al. The results demonstrated its strong reliability and validity, with a Cronbach's α coefficient of 0.82. The Chinese version comprises 13 items organized into three dimensions: spatial presence (Items 2, 3, 9), involvement (Items 1, 6, 10), and realism (Items 4, 5, 8, 11, 12, 13). Item 7 reflects overall presence. Each item employs a 7-point Likert scale ranging from -3 to 3 points, with items 10 and 12 reverse-scored. The total score ranges from -39 to 39 points, where a higher score indicates a better sense of presence experience in the virtual reality environment. Item 7 reflects overall presence. Each item uses a 7-point Likert scale ranging from -3 to 3 points, with items 10 and 12 reverse-scored. The total score rang
Time frame: The intervention will be implemented in November 2025, with the evaluation conducted after the 6-week intervention period concludes.
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