Comparing the Effects of Indoor vs. Outdoor Horticultural Therapy on College Students

This study used a randomised controlled trial to investigate the effects of different forms of horticultural group interventions on college students' depression, anxiety and subjective well-being, and the internal mechanisms of the effects.

Participants are required to complete the following tasks:

Attend one indoor/outdoor group gardening activity per week, lasting 2 hours each session, for a total of 8 weeks.

Complete psychological scale assessments at five time points: before the activity begins, at 4 weeks after the start, upon completion of the activity, and at 1 week and 2 weeks after completion.

Study Overview

• Status: Active, not recruiting
• Conditions: Healthy
• Intervention / Treatment: Behavioral: outdoor-horticultural therapy; Behavioral: indoor-Horticultural Therapy group; Behavioral: General Psychological Group Counselling Team

• Study Type: Interventional
• Enrollment (Estimated): 120
• Phase: Not Applicable

Contacts and Locations

Study Locations

• China
  • Beijing
    • Beijing, Beijing, China
      • Central University of Finance and Economics, Beijing, Beijing 100875

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

- University students

Exclusion Criteria:

• Diagnosed with a mental disorder

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: outdoor-horticultural; The participants in outdoor horticultural therapy engaged in weekly horticultural therapy activities outdoors for a total duration of eight weeks.	Behavioral: outdoor-horticultural therapy; Students are randomly assigned to the Outdoor Horticultural Therapy group, where they will receive outdoor horticultural therapy for eight weeks
Experimental: indoor-Horticultural; The participants in indoor horticultural therapy engaged in therapeutic gardening activities indoors once a week for a total duration of eight weeks.	Behavioral: indoor-Horticultural Therapy group; Students are randomly assigned to the indoor horticultural therapy group, where they will receive indoor horticultural therapy for 8 weeks
Placebo Comparator: General Psychological Group; Participants in the control group attended weekly psychological group sessions (without horticultural elements) for a total duration of eight weeks.	Behavioral: General Psychological Group Counselling Team; Students were randomly assigned to general group groups to participate in an 8-week mental health group activity
No Intervention: Blank control group; These participants did not engage in any psychological activities; they only regularly took part in questionnaire completion.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Depression	The Patient Health Questionnaire 9-item (PHQ-9): This scale consists of 9 items, each rated on a 4-point Likert scale, with higher scores indicating more severe depressive symptoms in the subject.	From enrollment to 2 weeks after the completion of the 8-week treatment Edit Copy Outcome
Anxiety	Generalized Anxiety Disorder 7-item Scale (GAD-7): This scale consists of 7 items, each rated on a 4-point Likert scale, with higher scores indicating more severe anxiety symptoms in the subjects.	From enrollment to 2 weeks after the completion of the 8-week treatment
Positive And Negative Affective	Positive and Negative Affect Schedule (PANAS): This scale consists of 20 items, including 10 positive affect items and 10 negative affect items, with each item rated on a Likert five-point scale. Higher scores on the positive affect items indicate higher levels of positive affect in the participants, while higher scores on the negative affect items indicate higher levels of negative affect in the participants.	From enrollment to 2 weeks after the completion of the 8-week treatment
Life satisfaction	The Satisfaction With Life Scale (SWLS): This scale consists of 5 items, each rated on a 7-point Likert scale, with higher scores indicating greater life satisfaction among participants.	From enrollment to 2 weeks after the completion of the 8-week treatment

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Resilience	The Connor-Davidson Resilience Scale (CD-RISC): The scale consists of 25 items divided into three dimensions-tenacity, self-reliance, and optimism. Each item is rated on a Likert five-point scale. Higher scores indicate greater psychological resilience in the subjects.	From enrollment to 2 weeks after the completion of the 8-week treatment
Loneliness	UCLA Loneliness Scale: This scale consists of 8 items, each rated on a 5-point Likert scale, with higher scores indicating stronger feelings of loneliness in the subjects.	From enrollment to 2 weeks after the completion of the 8-week treatment
Sense of control	Sense of Mastery Scale (SMS): This scale consists of 7 items, each using a 5-point Likert scale, with higher scores indicating a stronger sense of mastery in the subjects.	From enrollment to 2 weeks after the completion of the 8-week treatment
Avoidance	The Brief Experiential Avoidance Questionnaire (BEAQ) was initially simplified and revised by Gámez et al. based on the Multidimensional Experiential Avoidance Questionnaire to assess content related to experiential avoidance. Cao et al. conducted a Chinese version revision in 2021. The questionnaire consists of 15 items, with the cognitive avoidance dimension containing 8 items and the behavioral avoidance dimension containing 7 items, all rated on a 6-point scale from "Strongly Disagree" to "Strongly Agree."	From enrollment to 2 weeks after the completion of the 8-week treatment
Self-concept	Sense of Mastery Scale, SMS. This scale consists of 12 items, with each item rated on a five-point Likert scale. Higher scores indicate a clearer self-concept among the participants.	From enrollment to 2 weeks after the completion of the 8-week treatment
meaning in life	The Meaning in Life Questionnaire (MLQ): This scale consists of 10 items with two dimensions: Presence of Meaning (MLQ-P) and Search for Meaning (MLQ-S). Each item adopts a 7-point Likert scale, with higher scores indicating that participants experience a stronger sense of meaning in life.	From enrollment to 2 weeks after the completion of the 8-week treatment
Grit	The Grit Scale consists of 12 items with two dimensions: the Effort dimension and the Interest Consistency dimension. Each item is rated on a five-point Likert scale, with higher scores indicating that participants perceive themselves as more perseverant.	From enrollment to 2 weeks after the completion of the 8-week treatment
nature connection	The Nature Connection Scale, which consists of 14 items, employs a 5-point Likert scale for each item, with higher scores indicating that participants perceive themselves as more closely connected to nature.	From enrollment to 2 weeks after the completion of the 8-week treatment

Collaborators and Investigators

• Sponsor: Ye Zhiyin

Study record dates

Study Major Dates

• Study Start (Actual): March 20, 2025
• Primary Completion (Estimated): May 30, 2026
• Study Completion (Estimated): June 1, 2026

Study Registration Dates

• First Submitted: March 4, 2025
• First Submitted That Met QC Criteria: April 22, 2025
• First Posted (Actual): April 30, 2025

Study Record Updates

• Last Update Posted (Actual): April 30, 2025
• Last Update Submitted That Met QC Criteria: April 22, 2025
• Last Verified: March 1, 2025

More Information

Terms related to this study

• Other Study ID Numbers: cufe03

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No