Natural environments and adolescent depression: A literature review

Table 1 Overview of reviewed studies by research dimension

Category	Specific factors	Key findings/mechanisms	Ref.
Core factors	Green space (positive)	Reduces physiological stress, restores attention (attention restoration theory), and builds social capital	Markevych et al[27]; James et al[28]; Bloemsma et al[30]; Larsen et al[31]
		Long-term exposure in childhood predicts lower depression in early adulthood
		Ecological quality (e.g., biodiversity) matters more than quantity
	Blue space (positive)	Provides “soft fascination” and sensory stimulation (sound of water)	Gascon et al[50]; Pasanen et al[42]
		“Blue gym” effect: Promotes water-based physical activities
		Reduces internalization problems (depression/anxiety)
	Natural disasters (negative)	Short-term: Tornadoes, earthquakes, and floods trigger acute stress, posttraumatic stress disorder, and depression	Paul et al[52]; Feng et al[55]; Meltzer et al[64]; Proulx et al[70]
		Long-term: Disruption of social support and chronic stress from climate change lead to persistent psychological issues
Mediating mechanisms	Physical activity	Nature increases frequency/intensity of exercise (“environmental attractiveness”)	McCormick[77]; Lubans et al[78]; Thompson Coon et al[79]
		Neuroendocrine regulation through active behavior
	Social interaction	Nature serves as a “safe social haven” and “neutral medium”	Sugiyama et al[84]; Birch et al[86]
		Enhances social cohesion and reduces loneliness
	Positive psychological experiences	“Optimizing internal states”: Reduces rumination and enhances subjective well-being	Bratman et al[88]; Liu et al[89]; Marselle et al[98]
		Builds psychological resilience and self-efficacy
Moderating variables	Individual factors	Gender: Context-specific results (e.g., males benefit more from physical activity in nature; females from social support)	Larsen et al[31]; Liu et al[101]; Bratman et al[106]
		Behavioral problems: “Amplification effect”, adolescents with behavioral issues benefit more from nature’s nonjudgmental setting
	Environmental factors	SES: “Priority protective effect”, nature benefits low-SES adolescents more significantly	Mitchell et al[107]; Geary et al[108]; Beyer et al[115]; Anglin et al[116]
		Urbanization: “Stress compensation”, nature acts as an antidote to high-density urban stress
		Sunlight: Regulates vitamin D synthesis and circadian rhythms

SES: Socioeconomic status.