Nature-based Contemplation and Spiritual Well-being Among Adults With Moderate Prolonged Grief Symptoms

Nature-based Contemplation and Spiritual Well-being Among Adults With Moderate Prolonged Grief Symptoms: A Randomized Controlled Trial

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 Overview

• Status: Completed
• Conditions: Grief; Spiritual Wellbeing
• Intervention / Treatment: Behavioral: Noticing-nature; Behavioral: Nature-based contemplation

• Study Type: Interventional
• Enrollment (Actual): 262
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Netherlands
  • Enschede, Netherlands, 7522 NB
    • University of Twente

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Be a family member, spouse, or friend of a person who died at least 6 months prior to study enrollment;
• Be ≥18 years of age;
• Report moderate subclinical grief (score range from 47-70) based on the Traumatic Grief Inventory-Self Report Plus (TGI-SR+, Lenferink, Eisma, et al., 2022);
• Have access to a natural environment suitable for the intervention;
• Be willing and able to move in nature daily (with or without mobility assistance devices) and engage in brief mindfulness practices;
• Have sufficient Dutch language proficiency;
• Have access to Internet and mobile applications.

Exclusion Criteria:

• Acute suicide risk assessed in the screening step;
• A score lower than 47 or higher than 70 on TGI-SR+;
• Physical limitations that prevent moving outdoors for 30 minutes daily, even with mobility assistance devices.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Waitlist
Active Comparator: Noticing-nature; 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.	Behavioral: Noticing-nature; 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.
Experimental: Nature-based contemplation; 10 minutes walking to a chosen natural location, 10 minutes guided contemplation practice, 10 minutes walking back.	Behavioral: Nature-based contemplation; 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	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.	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.	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.	4 months after baseline

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	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.	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.	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.	4 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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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).	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).	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).	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).	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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).; Grief reactions (2 items); Positive affect (2 items); Negative affect (2 items); Nature connectedness (1 item; Schultz, 2001); Selflessness (1 item; Dambrun, 2016); Spiritual well-being (1 item; Underwood, 2011); Ability to adapt (1 item; Franken et al., 2023)Analysis metric: Daily fluctuations and sudden gains	From baseline to post-intervention (2-weeks)

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Demographic characteristics	Age, gender, education level, employment status	Baseline
Loss-related characteristics	(1) Relationship to the deceased (categorized as spouse/partner, child, parent, sibling, other family member, or friend); (2) Time since loss (measured in months since death occurred); and (3) Cause of death (categorized as natural anticipated, natural sudden, accident, suicide, homicide, or other/unknown). These variables will be reported using descriptive statistics, with categorical variables presented as frequencies and percentages, and continuous variables (time since loss) presented as means and standard deviations.	Baseline
Previous mindfulness experience	Using two complementary items. First, participants will respond to the question "Do you have experience with meditation?" with three response options: "Yes, I would call myself an expert and have a lot of experience with meditation," "Yes, I have a little experience with meditation," or "No, I have no experience with meditation (yet)." Second, current practice frequency will be assessed with the question "How many times have you meditated in the past month?" with four response options: "Daily," "Weekly," "Occasionally," or "Never."	Baseline
Previous Nature experience	Participants will respond to the question "Are you regularly in nature (such as the forest, a park or the beach)?" with five response options: "Yes, every day," "Yes, one or more times a week," "Yes, once a month," "No, rarely," or "No, never."	Baseline
Intervention adherence	A post-intervention adherence item measuring self-reported frequency of practice completion and duration of practice sessions. Adherence will be operationalized as the percentage of assigned sessions completed (ranging from 0-100%) and reported as means, standard deviations, and frequency distributions.	1 month after baseline
Co-intervention use	Participants will respond to the question: "During the past 2 weeks, did you receive additional psychological professional support from a psychologist, therapist, or psychiatrist for dealing with your emotional problems?" Results will be reported as frequencies and percentages. Co-intervention use will be examined as a potential confounding variable in the analysis to determine whether concurrent psychological support interacts with the intervention effects.	1 month after baseline
Client satisfaction measured by Client Satisfaction Questionnaire	Measured using 8-item Client Satisfaction Questionnaire (CSQ-8; Attkisson & Zwick, 1982). Items will be scored on a 4-point scale, and a sum score (8-32) will be calculated with higher scores being indicative of a larger satisfaction with the intervention.	1 month after baseline

Collaborators and Investigators

• Sponsor: University of Twente

Study record dates

Study Major Dates

• Study Start (Actual): March 24, 2025
• Primary Completion (Actual): October 1, 2025
• Study Completion (Actual): October 1, 2025

Study Registration Dates

• First Submitted: March 12, 2025
• First Submitted That Met QC Criteria: March 24, 2025
• First Posted (Actual): April 1, 2025

Study Record Updates

• Last Update Posted (Actual): May 5, 2026
• Last Update Submitted That Met QC Criteria: April 28, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: 250441

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
• product manufactured in and exported from the U.S.: No