Mood and physiological effects of visual stimulation with images of the natural environment in individuals with depressive and anxiety disorders

Tomohiro Mizumoto; Harumi Ikei; Kosuke Hagiwara; Toshio Matsubara; Fumihiro Higuchi; Masaaki Kobayashi; Takahiro Yamashina; Jun Sasaki; Norihiro Yamada; Naoko Higuchi; Kenichi Haraga; Fumiaki Kirihara; Emi Okabe; Kumi Asai; Masako Hirotsu; Chong Chen; Yoshifumi Miyazaki; Shin Nakagawa

doi:10.1016/j.jad.2024.04.025

Mood and physiological effects of visual stimulation with images of the natural environment in individuals with depressive and anxiety disorders

J Affect Disord. 2024 Jul 1:356:257-266. doi: 10.1016/j.jad.2024.04.025. Epub 2024 Apr 7.

Authors

Tomohiro Mizumoto¹, Harumi Ikei², Kosuke Hagiwara¹, Toshio Matsubara¹, Fumihiro Higuchi¹, Masaaki Kobayashi¹, Takahiro Yamashina¹, Jun Sasaki³, Norihiro Yamada¹, Naoko Higuchi¹, Kenichi Haraga¹, Fumiaki Kirihara¹, Emi Okabe¹, Kumi Asai¹, Masako Hirotsu¹, Chong Chen⁴, Yoshifumi Miyazaki², Shin Nakagawa¹

Affiliations

¹ Division of Neuropsychiatry, Department of Neuroscience, Yamaguchi University Graduate School of Medicine, Ube, Japan.
² Center for Environment, Health and Field Sciences, Chiba University, Chiba, Japan.
³ Division of Neuropsychiatry, Department of Neuroscience, Yamaguchi University Graduate School of Medicine, Ube, Japan; Koryo Hospital, Ube, Japan.
⁴ Division of Neuropsychiatry, Department of Neuroscience, Yamaguchi University Graduate School of Medicine, Ube, Japan. Electronic address: cchen@yamaguchi-u.ac.jp.

PMID: 38588725
DOI: 10.1016/j.jad.2024.04.025

Abstract

Background: Nature therapies are gaining attention as non-pharmacological treatments for depressive and anxiety disorders, but research on their effectiveness in patients is limited. This study investigates the mood-improving effects of visual stimulation with natural environmental images in patients with depressive and anxiety disorders.

Methods: We conducted a randomized crossover comparison trial involving 60 right-handed adult participants with depressive or anxiety disorders and receiving outpatient treatment. Visual stimuli of natural environments consisted of green-themed nature images, while the control stimuli featured urban scenes dominated by buildings. The stimulation lasted for 3 min, during which orbital prefrontal brain activity was measured using a 2-channel Near-infrared Spectroscopy (NIRS) system, and heart rate variability was assessed using fingertip accelerated plethysmography.

Results: Mood enhancement effects were observed in both the depressive and anxiety disorder groups following visual stimulation with nature images. In the depression group, orbital prefrontal oxygenated hemoglobin concentration significantly increased after visual stimulation with nature images, while there were no significant changes in the anxiety group. However, in the anxiety group, a correlation was found between reduced orbital prefrontal oxygenated hemoglobin in response to nature images and increased mood-enhancement. Furthermore, the severity of depressive symptoms did not significantly affect the intervention effects, whereas heightened anxiety symptoms was associated with a smaller mood enhancement effect.

Discussion: Our study demonstrates the benefits of nature image stimulation for patients with depressive and anxiety disorders. Differential orbital prefrontal brain activity impacts notwithstanding, both conditions exhibited mood enhancement, affirming the value of nature image stimulation.

Keywords: Heart rate variability; Mood; Nature therapy; Near-infrared spectroscopy; Prefrontal cortex.

Publication types

Randomized Controlled Trial
Research Support, Non-U.S. Gov't

MeSH terms

Adult
Affect* / physiology
Anxiety Disorders* / physiopathology
Anxiety Disorders* / therapy
Cross-Over Studies*
Depressive Disorder / physiopathology
Depressive Disorder / therapy
Environment
Female
Heart Rate* / physiology
Humans
Male
Middle Aged
Nature
Photic Stimulation*
Prefrontal Cortex* / physiopathology
Spectroscopy, Near-Infrared*
Young Adult