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

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.

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.

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.

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.

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.

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.

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.

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."

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.

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.

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.

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.