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.”
Watkins-Martin K, Bolani D, Richard-Devantoy S, et al. The effects of walking in nature on negative and positive affect in adult psychiatric outpatients with major depressive disorder: a randomized-controlled study. J Affect Disord. 2022;318:291-298. doi:10.1016/j.jad.2022.08.121