Effectiveness of Nature Walks in Depressed Adults

McGill University47 enrolled

Overview

Over the past few years, a growing number of campaigns from around the world, including Canada, are highlighting the positive impact of spending time in nature on well-¬being. Indeed, mounting evidence suggests that spending time with nature is associated with a myriad of affective and cognitive benefits. Surprisingly few studies to date have tested the assumption that walking in nature versus in urban settings could alleviate stress and depressive symptoms in clinically depressed adults. The main purpose of this study is to investigate the effectiveness of walking in nature versus in urban settings to improve depression related symptoms and reduce stress. The trial initially included 2 primary outcomes: patients stress levels (salivary cortisol) and depression-related symptoms (eg, affect, rumination, executive functioning). However, due to hygienic concerns in light of the COVID-19 pandemic in 2020, the collection of saliva samples (and in turn, the measurement of stress levels via salivary cortisol) was removed from the study's procedure. The main outcome was changed to effects on positive and negative affect.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

SUPPORTIVE_CARE

Masking

SINGLE

Enrollment

Conditions

Experimental

Interventions

Eligibility

Sex: ALLMin age: 18 YearsMax age: 65 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Men and women aged between 18 and 65 years, inclusively; * Ability to speak French or English; * Diagnosis major depressive disorder (DSM-IV); Exclusion Criteria: * Acute psychotic symptoms; * Acute suicidal intent (within 48 hours); * Unable to walk for 60 min or serious medical reasons (e.g. major surgery) * Heart condition as per history or detected on electrocardiogram

Outcomes

Primary Outcomes

Change in affect from baseline up to 48 hours post-walk

Positive and Negative Affect Schedule (PANAS)

Time frame: Day 1 to Day 3

Secondary Outcomes

Change in Executive Functions

The stroop color word test is a widely used task to assess selective attention and inhibitory control. In the first block of this task (A), color words (red, blue, yellow, green) printed in black ink are presented in random order and participants are asked to read out loud the words. In the second block (B), solid color patches in one of the same four colors are shown and participants name the colors. Finally, in the third block (C), color words are printed in an incongruous ink color and participants must name the ink color (e.g. GREEN \[typed in red\]; response = red). Participants are asked to complete each block as quickly and accurately as possible and the time to complete each trial is calculated and averaged for each block. An interference score is calculated as followed: C - \[(A + B) /2\].

Time frame: The Stroop test will be administered at 2 time points: 1) before the walk (between 9:45-10:30); 2) after the walk (between 11:30-11:50)

Change in suicidal Ideations

Severity of Suicidal Ideations The severity of current suicidal ideation will be assessed with three items derived from a prior study of momentary assessment of suicidal risk: "How intense is your desire to kill yourself right now"?; "How strong is your intention to kill yourself right now"?; "How strong is your ability to resist the urge to kill yourself right now"? Each item is scored on a scale from 0 (not strong \[intense\] at all) to 4 (very strong \[intense\]).

Time frame: Day 1

Change in depressive symptoms

The Beck Depression Inventory (BDI-II) The BDI is a widely used 21-item depression inventory with good internal consistency (α = .93 in the current sample) and validity. Items are answered on a 4-point scale from 0 to 3.

Time frame: Day 1 to Day 2

Change in rumination

The Rumination-Reflection Questionnaire (RRQ) The RRQ is a 24-item self-reported questionnaire assessing both self-rumination and self-reflection, 57 with 12 items corresponding to each subscale. Participants rate the degree to which they engage in self- rumination (e.g. "sometimes it is hard for me to shut off thoughts about myself") and self-reflective thoughts (e.g. "I love to meditate on the nature and meaning of things") on a Likert scale ranging from one (strongly disagree) to five (strongly agree)