Walking in Nature May Improve Negative Major Depressive Disorder Symptoms

Walking in nature may improve negative symptoms for patients with major depressive disorder (MDD), according to study results published in Journal of Affective Disorders.

Patients (N=37; mean age 49.27 [SD, 10.95] years; 67.6% women) with MDD were recruited from the Douglas Mental Health University Institute in Canada between 2019 and 2021. Study participants were randomly assigned in a 1:1 ratio to go on nature (n=20) or urban (n=17) walks. The walks occurred between 8:00 am and 12:00 pm and included 1 or 2 participants who were accompanied by 2 research assistants. The walks lasted 60 minutes, and were paced at 3 to 5 km per hour.

Participants were instructed to refrain from social engagement during walks. The nature walks occurred in a 97-hectare biodiversity urban park near the study site and totaled 4.41 km. The urban walks occurred on the busiest street near the study site with 3 to 4 lanes of automobile traffic and totaled 4.46 km. The primary outcome was the change in Positive and Negative Affect Schedule (PANAS) scores.

Among the study population, 64.9% were single, 67.6% were unemployed, 37.8% had a previous psychiatric hospitalization, 91.9% currently received psychiatric medications, respectively, and Hamilton Depression Rating Scale score was 15.43 (SD, 5.88) points.

Stratified by condition, participants who went on the nature walk had significantly lower PANAS-Negative symptom scores during the following times:

• Before the walk (mean, 18.80 vs 25.06; P =.022);
• During the walk (mean, 13.45 vs 17.77; P =.031);
• Immediately after the walk (mean, 12.00 vs 17.11; P =.005);
• Before bedtime (mean, 13.78 vs 21.00; P =.005);
• 24 hours after the walk (mean, 15.00 vs 23.25; P <.001); and
• 48 hours after the walk (mean, 16.28 vs 23.33; P =.017).

No significant effects were observed for PANAS-Positive symptom scores (all P ≥.294).

In the final model, a significant effect of condition was observed on PANAS-Negative symptom scores (F_[1,35.039], 4.239; P =.047) and a significant effect of time was observed for PANAS-Positive symptom scores (F_[4,127.556], 6.059; P <.001).

The major limitation of this study was the significantly lower PANAS-Negative symptom scores prewalk observed among the nature group.

Study authors concluded, “Our results suggest that walking in nature might be a useful complementary strategy to improve negative affect in the short-term for individuals diagnosed with MDD. Prior evidence suggests that wilderness therapy and group walks in nature can serve as complementary treatment options for adults with depression. […] Further investigation of these potential mediators, as well as the optimal elements and doses of nature exposure, would enable clinicians to target key processes and improve the efficacy of nature-based interventions.”