This study aimed to systematically examine and meta-analyze the effectiveness of aromatherapy in alleviating stress, depressive symptoms, and sleep disturbances among adult populations. A comprehensive literature search was conducted following PRISMA ...
This study aimed to systematically examine and meta-analyze the effectiveness of aromatherapy in alleviating stress, depressive symptoms, and sleep disturbances among adult populations. A comprehensive literature search was conducted following PRISMA 2020 guidelines, and 70 studies on stress, 28 on depression, and 39 on sleep were included in the final analysis. Random-effects models were applied, and publication bias was assessed using Egger's regression test and the Trim-and-Fill method.
The meta-analysis revealed significant effects of aromatherapy across all three outcome domains. For stress reduction, aromatherapy demonstrated a medium effect size (ES=0.70, 95% CI: 0.57~0.81, p<.001), which remained significant after correcting for publication bias (ES=0.67, 95% CI: 0.51~0.79, p<.001). For depressive symptoms, a medium effect size was observed (ES=0.67, 95% CI: 0.44~0.83, p<.001); however, substantial publication bias was detected, and the corrected effect size became non-significant (ES=0.31, 95% CI: -0.07~0.63). For sleep improvement, aromatherapy showed a small but significant effect (ES=-0.37, 95% CI: -0.58~-0.13, p<.01) with no evidence of publication bias.
Hypothesis testing confirmed that all six research hypotheses were supported, either fully or partially. Main hypotheses regarding stress (H1), depression (H2, conditional), and sleep (H3) were accepted. Subgroup analyses revealed that both inhalation and combined intervention methods were effective for stress (H4), with combined interventions showing superior effects for depression (H₅). For sleep, only inhalation demonstrated significant effects, though the effect size was reduced after statistical adjustment (H₆).
These findings provide quantitative evidence that aromatherapy exerts meaningful effects on mitigating stress responses, relieving depression, and improving overall sleep quality. The therapeutic mechanisms appear to be primarily driven by essential oils' influence on the limbic system and autonomic nervous system through olfactory stimulation, thereby regulating neurotransmitters such as serotonin and dopamine, and reducing cortisol levels. The inclusion of publication bias assessment and correction procedures helped prevent confirmation bias and enhanced the clinical validity of the findings.
Nevertheless, this study highlights several challenges and directions for future research. First, variations in essential oil types, concentrations, and quality control measures may yield inconsistent results across studies. Second, individual factors such as personal scent preferences, allergies, and comorbid health conditions can moderate aromatherapy outcomes. Third, most existing investigations have focused on short-term interventions, leaving questions regarding long-term efficacy and relapse prevention relatively underexplored. Therefore, longitudinal designs and larger-scale randomized controlled trials are needed to elucidate the sustained effects and safety profile of aromatherapy. Additionally, greater standardization and the development of clinical guidelines—including specific recommendations on optimal oil selection, dilution ratios, and administration protocols—will help ensure consistent and safe implementation in both clinical and community settings.
Overall, the findings support the notion that aromatherapy can serve as an accessible and beneficial complementary modality for individuals coping with stress, depression, or sleep-related problems. By providing a natural, user-friendly avenue for managing psychological and physiological burdens, aromatherapy holds significant potential for enhancing the mental health and overall quality of life of adult populations worldwide.