The goal of this randomized controlled trial is to evaluate whether a nature-based contemplation intervention can enhance spiritual well-being and reduce grief symptoms among adults with moderate prolonged grief symptoms. The main questions it aims to answer are: Does a nature-based contemplation intervention improve spiritual well-being compared to an active control condition (noticing nature) and a waitlist control condition? Does a nature-based contemplation intervention reduce grief severity and improve mental well-being, nature connectedness, selflessness, ability to adapt, personal recovery, and elevation compared to control conditions? How do spiritual well-being, ability to adapt, nature connectedness, selflessness, grief reactions, and positive/negative affect change during the intervention period? Researchers will compare a nature-based contemplation intervention to both a noticing-nature active control group and a waitlist control group to isolate mindfulness-specific effects from possible general nature exposure benefits. Participants will: Complete baseline, post-intervention, and follow-up assessments (at one and three months) Engage in either 10 sessions of nature-based contemplation practice or noticing nature activities over a two-week period (intervention and active control groups) Provide daily diary responses about their experiences throughout the 14-day intervention period
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
SUPPORTIVE_CARE
Masking
NONE
Enrollment
262
The intervention consisted of a daily 30-minute self-guided practice structured in three parts: (1) participants first walked mindfully for 10 minutes in a natural environment of their choosing (e.g., local park, forest, garden), (2) upon reaching a suitable location, they engaged in a 10-minute guided contemplative practice, and (3) concluded with a 10-minute mindful walk back.
Participants allocated to the noticing-nature active control group will be instructed to walk in nature for 30 minutes per day and pay attention to how the natural objects/scenes they encounter in their daily surroundings make them feel over the 14-day period.
University of Twente
Enschede, Netherlands
Spiritual well-being measured by Spiritual Attitude and Involvement List-Short Form
Measured using the Spiritual Attitude and Involvement List-Short Form (SAIL-SF; Bohlmeijer et al., 2023). The SAIL-SF measures seven dimensions of spiritual well-being: meaningfulness, trust, acceptance, caring for others, connectedness with nature, transcendent experiences, and spiritual activities. Each dimension is assessed by one item (e.g., "I experience the things I do as meaningful", "I try to take life as it comes"). Items are rated on a 6-point Likert scale ranging from 1 (not at all) to 6 (to a very high degree), with higher scores indicating greater spiritual well-being. The total score is calculated as the mean of all items.
Time frame: Baseline
Spiritual well-being measured by Spiritual Attitude and Involvement List-Short Form
Measured using the Spiritual Attitude and Involvement List-Short Form (SAIL-SF; Bohlmeijer et al., 2023). The SAIL-SF measures seven dimensions of spiritual well-being: meaningfulness, trust, acceptance, caring for others, connectedness with nature, transcendent experiences, and spiritual activities. Each dimension is assessed by one item (e.g., "I experience the things I do as meaningful", "I try to take life as it comes"). Items are rated on a 6-point Likert scale ranging from 1 (not at all) to 6 (to a very high degree), with higher scores indicating greater spiritual well-being. The total score is calculated as the mean of all items.
Time frame: 1 month after baseline
Spiritual well-being measured by Spiritual Attitude and Involvement List-Short Form
Measured using the Spiritual Attitude and Involvement List-Short Form (SAIL-SF; Bohlmeijer et al., 2023). The SAIL-SF measures seven dimensions of spiritual well-being: meaningfulness, trust, acceptance, caring for others, connectedness with nature, transcendent experiences, and spiritual activities. Each dimension is assessed by one item (e.g., "I experience the things I do as meaningful", "I try to take life as it comes"). Items are rated on a 6-point Likert scale ranging from 1 (not at all) to 6 (to a very high degree), with higher scores indicating greater spiritual well-being. The total score is calculated as the mean of all items.
Time frame: 2 months after baseline
Spiritual well-being measured by Spiritual Attitude and Involvement List-Short Form
Measured using the Spiritual Attitude and Involvement List-Short Form (SAIL-SF; Bohlmeijer et al., 2023). The SAIL-SF measures seven dimensions of spiritual well-being: meaningfulness, trust, acceptance, caring for others, connectedness with nature, transcendent experiences, and spiritual activities. Each dimension is assessed by one item (e.g., "I experience the things I do as meaningful", "I try to take life as it comes"). Items are rated on a 6-point Likert scale ranging from 1 (not at all) to 6 (to a very high degree), with higher scores indicating greater spiritual well-being. The total score is calculated as the mean of all items.
Time frame: 4 months after baseline
Grief intensity measured by Traumatic Grief Inventory-Self Report Plus
Measured using the 22-item Traumatic Grief Inventory-Self Report Plus (TGI-SR+; Lenferink et al., 2022). Participants rated the extent to which they experienced each grief symptom during the past two weeks on 5-point Likert scale (1 = never to 5 = always). Total scores are calculated by summing all items (range: 22-110), with higher scores indicating greater grief intensity. A total score ≥71 indicates probable clinical DSM-5-TR PGD.
Time frame: Baseline
Grief intensity measured by Traumatic Grief Inventory-Self Report Plus
Measured using the 22-item Traumatic Grief Inventory-Self Report Plus (TGI-SR+; Lenferink et al., 2022). Participants rated the extent to which they experienced each grief symptom during the past two weeks on 5-point Likert scale (1 = never to 5 = always). Total scores are calculated by summing all items (range: 22-110), with higher scores indicating greater grief intensity. A total score ≥71 indicates probable clinical DSM-5-TR PGD.
Time frame: 1 month after baseline
Grief intensity measured by Traumatic Grief Inventory-Self Report Plus
Measured using the 22-item Traumatic Grief Inventory-Self Report Plus (TGI-SR+; Lenferink et al., 2022). Participants rated the extent to which they experienced each grief symptom during the past two weeks on 5-point Likert scale (1 = never to 5 = always). Total scores are calculated by summing all items (range: 22-110), with higher scores indicating greater grief intensity. A total score ≥71 indicates probable clinical DSM-5-TR PGD.
Time frame: 2 months after baseline
Grief intensity measured by Traumatic Grief Inventory-Self Report Plus
Measured using the 22-item Traumatic Grief Inventory-Self Report Plus (TGI-SR+; Lenferink et al., 2022). Participants rated the extent to which they experienced each grief symptom during the past two weeks on 5-point Likert scale (1 = never to 5 = always). Total scores are calculated by summing all items (range: 22-110), with higher scores indicating greater grief intensity. A total score ≥71 indicates probable clinical DSM-5-TR PGD.
Time frame: 4 months after baseline
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Nature connectedness measured by Inclusion of Nature in Self scale
Measured using 1-item Inclusion of Nature in Self scale (INS; Schultz, 2001). The INS is a single-item pictorial measure that assesses the extent to which individuals include nature within their cognitive representation of self. The measure consists of seven pairs of circles labeled "self" and "nature" with varying degrees of overlap, from completely separate (1) to almost completely overlapping (7). Participants select the picture that best describes their relationship with the natural environment.
Time frame: Baseline
Nature connectedness measured by Inclusion of Nature in Self scale
Measured using 1-item Inclusion of Nature in Self scale (INS; Schultz, 2001). The INS is a single-item pictorial measure that assesses the extent to which individuals include nature within their cognitive representation of self. The measure consists of seven pairs of circles labeled "self" and "nature" with varying degrees of overlap, from completely separate (1) to almost completely overlapping (7). Participants select the picture that best describes their relationship with the natural environment.
Time frame: 1 month after baseline
Nature connectedness measured by Inclusion of Nature in Self scale
Measured using 1-item Inclusion of Nature in Self scale (INS; Schultz, 2001). The INS is a single-item pictorial measure that assesses the extent to which individuals include nature within their cognitive representation of self. The measure consists of seven pairs of circles labeled "self" and "nature" with varying degrees of overlap, from completely separate (1) to almost completely overlapping (7). Participants select the picture that best describes their relationship with the natural environment.
Time frame: 2 months after baseline
Nature connectedness measured by Inclusion of Nature in Self scale
Measured using 1-item Inclusion of Nature in Self scale (INS; Schultz, 2001). The INS is a single-item pictorial measure that assesses the extent to which individuals include nature within their cognitive representation of self. The measure consists of seven pairs of circles labeled "self" and "nature" with varying degrees of overlap, from completely separate (1) to almost completely overlapping (7). Participants select the picture that best describes their relationship with the natural environment.
Time frame: 4 months after baseline
Nature connectedness measured by Connectedness to Nature Scale
Measured using 14-item Connectedness to Nature Scale (CNS; Mayer \& Frantz, 2004). The CNS measures individuals' trait levels of feeling emotionally and experientially connected to the natural world. Participants rated items such as "I often feel a sense of oneness with the natural world around me" and "I think of the natural world as a community to which I belong" on a 5-point Likert scale (1 = strongly disagree to 5 = strongly agree). The total score is calculated as the mean of all items after reverse-scoring items 4, 12, and 14, with higher scores indicating greater connectedness to nature.
Time frame: Baseline
Nature connectedness measured by Connectedness to Nature Scale
Measured using 14-item Connectedness to Nature Scale (CNS; Mayer \& Frantz, 2004). The CNS measures individuals' trait levels of feeling emotionally and experientially connected to the natural world. Participants rated items such as "I often feel a sense of oneness with the natural world around me" and "I think of the natural world as a community to which I belong" on a 5-point Likert scale (1 = strongly disagree to 5 = strongly agree). The total score is calculated as the mean of all items after reverse-scoring items 4, 12, and 14, with higher scores indicating greater connectedness to nature.
Time frame: 1 month after baseline
Nature connectedness measured by Connectedness to Nature Scale
Measured using 14-item Connectedness to Nature Scale (CNS; Mayer \& Frantz, 2004). The CNS measures individuals' trait levels of feeling emotionally and experientially connected to the natural world. Participants rated items such as "I often feel a sense of oneness with the natural world around me" and "I think of the natural world as a community to which I belong" on a 5-point Likert scale (1 = strongly disagree to 5 = strongly agree). The total score is calculated as the mean of all items after reverse-scoring items 4, 12, and 14, with higher scores indicating greater connectedness to nature.
Time frame: 2 months after baseline
Nature connectedness measured by Connectedness to Nature Scale
Measured using 14-item Connectedness to Nature Scale (CNS; Mayer \& Frantz, 2004). The CNS measures individuals' trait levels of feeling emotionally and experientially connected to the natural world. Participants rated items such as "I often feel a sense of oneness with the natural world around me" and "I think of the natural world as a community to which I belong" on a 5-point Likert scale (1 = strongly disagree to 5 = strongly agree). The total score is calculated as the mean of all items after reverse-scoring items 4, 12, and 14, with higher scores indicating greater connectedness to nature.
Time frame: 4 months after baseline
Mental well-being measured by Mental Health Continuum-Short Form
Measured using the Mental Health Continuum-Short Form (MHC-SF; Lamers et al., 2011), a 14-item scale measuring three dimensions of well-being: emotional (3 items), psychological (6 items), and social well-being (5 items). Participants rated the frequency of experiencing various feelings of well-being during the past month on a 6-point Likert scale (0 = never to 5 = every day). Scores are calculated as the mean of all items, with higher scores indicating greater well-being.
Time frame: Baseline
Mental well-being measured by Mental Health Continuum-Short Form
Measured using the Mental Health Continuum-Short Form (MHC-SF; Lamers et al., 2011), a 14-item scale measuring three dimensions of well-being: emotional (3 items), psychological (6 items), and social well-being (5 items). Participants rated the frequency of experiencing various feelings of well-being during the past month on a 6-point Likert scale (0 = never to 5 = every day). Scores are calculated as the mean of all items, with higher scores indicating greater well-being.
Time frame: 1 month after baseline
Mental well-being measured by Mental Health Continuum-Short Form
Measured using the Mental Health Continuum-Short Form (MHC-SF; Lamers et al., 2011), a 14-item scale measuring three dimensions of well-being: emotional (3 items), psychological (6 items), and social well-being (5 items). Participants rated the frequency of experiencing various feelings of well-being during the past month on a 6-point Likert scale (0 = never to 5 = every day). Scores are calculated as the mean of all items, with higher scores indicating greater well-being.
Time frame: 2 months after baseline
Mental well-being measured by Mental Health Continuum-Short Form
Measured using the Mental Health Continuum-Short Form (MHC-SF; Lamers et al., 2011), a 14-item scale measuring three dimensions of well-being: emotional (3 items), psychological (6 items), and social well-being (5 items). Participants rated the frequency of experiencing various feelings of well-being during the past month on a 6-point Likert scale (0 = never to 5 = every day). Scores are calculated as the mean of all items, with higher scores indicating greater well-being.
Time frame: 4 months after baseline
Selflessness measured by Perceived Body Boundaries Scale
Perceived Body Boundaries Scale (PBBS; Dambrun, 2016). This scale comprises a single item designed to assess the strength of participants' perceived body boundaries. A series of images of human forms with increasingly transparent boundaries to indicate gradations of body boundary salience. "Which images best represent your perception of your body's boundaries right now?" Responses range from 1 (no boundary dissolution) to 7 (a lot of boundary dissolution).
Time frame: Baseline
Selflessness measured by Perceived Body Boundaries Scale
Perceived Body Boundaries Scale (PBBS; Dambrun, 2016). This scale comprises a single item designed to assess the strength of participants' perceived body boundaries. A series of images of human forms with increasingly transparent boundaries to indicate gradations of body boundary salience. "Which images best represent your perception of your body's boundaries right now?" Responses range from 1 (no boundary dissolution) to 7 (a lot of boundary dissolution).
Time frame: 1 month after baseline
Selflessness measured by Perceived Body Boundaries Scale
Perceived Body Boundaries Scale (PBBS; Dambrun, 2016). This scale comprises a single item designed to assess the strength of participants' perceived body boundaries. A series of images of human forms with increasingly transparent boundaries to indicate gradations of body boundary salience. "Which images best represent your perception of your body's boundaries right now?" Responses range from 1 (no boundary dissolution) to 7 (a lot of boundary dissolution).
Time frame: 2 months after baseline
Selflessness measured by Perceived Body Boundaries Scale
Perceived Body Boundaries Scale (PBBS; Dambrun, 2016). This scale comprises a single item designed to assess the strength of participants' perceived body boundaries. A series of images of human forms with increasingly transparent boundaries to indicate gradations of body boundary salience. "Which images best represent your perception of your body's boundaries right now?" Responses range from 1 (no boundary dissolution) to 7 (a lot of boundary dissolution).
Time frame: 4 months after baseline
Selflessness measured by Spatial Frame of Reference Continuum
Spatial Frame of Reference Continuum (SFoRC; Hanley \& Garland, 2019). This scale comprises a single item used to assess the extent to which the field of awareness is perceived to extend beyond the physical body. How far does your self extend into the world? Using the letters and image below, please indicate how far you feel that your self extends beyond your physical body. "A" represents your self stopping at your physical body. "F" represents your self extending into everything (e.g., the entire Universe). The letters inbetween "A" and "F" represent different levels of self-extension. The rings are symbolic, and do not represent actual distances.
Time frame: Baseline
Selflessness (Spatial Frame of Reference Continuum)
Spatial Frame of Reference Continuum (SFoRC; Hanley \& Garland, 2019). This scale comprises a single item used to assess the extent to which the field of awareness is perceived to extend beyond the physical body. How far does your self extend into the world? Using the letters and image below, please indicate how far you feel that your self extends beyond your physical body. "A" represents your self stopping at your physical body. "F" represents your self extending into everything (e.g., the entire Universe). The letters inbetween "A" and "F" represent different levels of self-extension. The rings are symbolic, and do not represent actual distances.
Time frame: 1 month after baseline
Selflessness measured by Spatial Frame of Reference Continuum
Spatial Frame of Reference Continuum (SFoRC; Hanley \& Garland, 2019). This scale comprises a single item used to assess the extent to which the field of awareness is perceived to extend beyond the physical body. How far does your self extend into the world? Using the letters and image below, please indicate how far you feel that your self extends beyond your physical body. "A" represents your self stopping at your physical body. "F" represents your self extending into everything (e.g., the entire Universe). The letters inbetween "A" and "F" represent different levels of self-extension. The rings are symbolic, and do not represent actual distances.
Time frame: 2 months after baseline
Selflessness measured by Spatial Frame of Reference Continuum
Spatial Frame of Reference Continuum (SFoRC; Hanley \& Garland, 2019). This scale comprises a single item used to assess the extent to which the field of awareness is perceived to extend beyond the physical body. How far does your self extend into the world? Using the letters and image below, please indicate how far you feel that your self extends beyond your physical body. "A" represents your self stopping at your physical body. "F" represents your self extending into everything (e.g., the entire Universe). The letters inbetween "A" and "F" represent different levels of self-extension. The rings are symbolic, and do not represent actual distances.
Time frame: 4 months after baseline
Elevation measured by Elevating Experiences Scale
Measured using the Elevating Experiences Scale (EES; Huta \& Ryan, 2010), a 13-item measure that captures feelings of transcendence, moral inspiration, and connection to something greater than oneself. Participants rated their experiences over the past two weeks using a 7-point Likert-type scale ranging from 1 (not at all) to 7 (extremely). Scores are calculated as the mean of all items, with higher scores indicating greater elevation.
Time frame: Baseline
Elevation measured by Elevating Experiences Scale
Measured using the Elevating Experiences Scale (EES; Huta \& Ryan, 2010), a 13-item measure that captures feelings of transcendence, moral inspiration, and connection to something greater than oneself. Participants rated their experiences over the past two weeks using a 7-point Likert-type scale ranging from 1 (not at all) to 7 (extremely). Scores are calculated as the mean of all items, with higher scores indicating greater elevation.
Time frame: 1 month after baseline
Elevation measured by Elevating Experiences Scale
Measured using the Elevating Experiences Scale (EES; Huta \& Ryan, 2010), a 13-item measure that captures feelings of transcendence, moral inspiration, and connection to something greater than oneself. Participants rated their experiences over the past two weeks using a 7-point Likert-type scale ranging from 1 (not at all) to 7 (extremely). Scores are calculated as the mean of all items, with higher scores indicating greater elevation.
Time frame: 2 months after baseline
Elevation measured by Elevating Experiences Scale
Measured using the Elevating Experiences Scale (EES; Huta \& Ryan, 2010), a 13-item measure that captures feelings of transcendence, moral inspiration, and connection to something greater than oneself. Participants rated their experiences over the past two weeks using a 7-point Likert-type scale ranging from 1 (not at all) to 7 (extremely). Scores are calculated as the mean of all items, with higher scores indicating greater elevation.
Time frame: 4 months after baseline
Ability to adapt measured by Generic Sense of Ability to Adapt Scale
Measured using the Generic Sense of Ability to Adapt Scale (GSAAS; Franken et al., 2023). The GSAAS is a 10-item scale measuring perceived ability to readjust and actively deal with the psychosocial consequences of challenging events. Items (e.g., "If something unexpected happens, I can easily adapt") are rated on a 5-point Likert scale from "not at all" (0) to "always" (4). The total score is calculated as the mean of all items, with higher scores indicating greater ability to adapt.
Time frame: Baseline
Ability to adapt measured by Generic Sense of Ability to Adapt Scale
Measured using the Generic Sense of Ability to Adapt Scale (GSAAS; Franken et al., 2023). The GSAAS is a 10-item scale measuring perceived ability to readjust and actively deal with the psychosocial consequences of challenging events. Items (e.g., "If something unexpected happens, I can easily adapt") are rated on a 5-point Likert scale from "not at all" (0) to "always" (4). The total score is calculated as the mean of all items, with higher scores indicating greater ability to adapt.
Time frame: 1 month after baseline
Ability to adapt measured by Generic Sense of Ability to Adapt Scale
Measured using the Generic Sense of Ability to Adapt Scale (GSAAS; Franken et al., 2023). The GSAAS is a 10-item scale measuring perceived ability to readjust and actively deal with the psychosocial consequences of challenging events. Items (e.g., "If something unexpected happens, I can easily adapt") are rated on a 5-point Likert scale from "not at all" (0) to "always" (4). The total score is calculated as the mean of all items, with higher scores indicating greater ability to adapt.
Time frame: 2 months after baseline
Ability to adapt measured by Generic Sense of Ability to Adapt Scale
Measured using the Generic Sense of Ability to Adapt Scale (GSAAS; Franken et al., 2023). The GSAAS is a 10-item scale measuring perceived ability to readjust and actively deal with the psychosocial consequences of challenging events. Items (e.g., "If something unexpected happens, I can easily adapt") are rated on a 5-point Likert scale from "not at all" (0) to "always" (4). The total score is calculated as the mean of all items, with higher scores indicating greater ability to adapt.
Time frame: 4 months after baseline
Personal recovery measured by Brief INSPIRE-O
Measured using the 5-item Brief INSPIRE-O, modified from the Brief INSPIRE support measure (Williams et al., 2015). Items are rated on a 5-point Likert scale from 0 (not at all) to 4 (very much). Following scoring guidelines (Moeller et al., 2023), raw scores were summed and multiplied by 5 to give a total score ranging from 0 to 100, with higher scores indicating better personal functioning.
Time frame: Baseline
Personal recovery measured by Brief INSPIRE-O
Measured using the 5-item Brief INSPIRE-O, modified from the Brief INSPIRE support measure (Williams et al., 2015). Items are rated on a 5-point Likert scale from 0 (not at all) to 4 (very much). Following scoring guidelines (Moeller et al., 2023), raw scores were summed and multiplied by 5 to give a total score ranging from 0 to 100, with higher scores indicating better personal functioning.
Time frame: 1 month after baseline
Personal recovery measured by Brief INSPIRE-O
Measured using the 5-item Brief INSPIRE-O, modified from the Brief INSPIRE support measure (Williams et al., 2015). Items are rated on a 5-point Likert scale from 0 (not at all) to 4 (very much). Following scoring guidelines (Moeller et al., 2023), raw scores were summed and multiplied by 5 to give a total score ranging from 0 to 100, with higher scores indicating better personal functioning.
Time frame: 2 months after baseline
Personal recovery measured by Brief INSPIRE-O
Measured using the 5-item Brief INSPIRE-O, modified from the Brief INSPIRE support measure (Williams et al., 2015). Items are rated on a 5-point Likert scale from 0 (not at all) to 4 (very much). Following scoring guidelines (Moeller et al., 2023), raw scores were summed and multiplied by 5 to give a total score ranging from 0 to 100, with higher scores indicating better personal functioning.
Time frame: 4 months after baseline
Daily diary (assessed daily during 14-day intervention period)
"Please respond to the following items based on your experiences and feelings today, reflecting specifically on the past 24 hours." Responses range from 1 (not at all) to 7 (very much). 1. Grief reactions (2 items) 2. Positive affect (2 items) 3. Negative affect (2 items) 4. Nature connectedness (1 item; Schultz, 2001) 5. Selflessness (1 item; Dambrun, 2016) 6. Spiritual well-being (1 item; Underwood, 2011) 7. Ability to adapt (1 item; Franken et al., 2023) * Analysis metric: Daily fluctuations and sudden gains
Time frame: From baseline to post-intervention (2-weeks)