Inhalation Aromatherapy for Improving Sleep Quality in Adults: A Systematic Review and Meta-analysis of Trials Using the Pittsburgh Sleep Quality Index (PSQI)

Abstract

Adults frequently experience sleep disturbances, which add to their health burden. Although inhalation aromatherapy is an inexpensive, non-pharmacological approach, evidence based on standardized assessments remains inconsistent. We conducted a PRISMA 2020-guided systematic review and meta-analysis of controlled clinical trials in adults aged 18-65 years, searching PubMed and Google Scholar in December 2025. Eligible trials compared inhalation aromatherapy with a control condition and reported post-intervention Pittsburgh Sleep Quality Index (PSQI) total score. We pooled standardized mean differences using a random-effects model (Hedges' g). After screening 219 titles/abstracts and assessing 51 full texts, nine studies met inclusion criteria and five contributed to the meta-analysis. Aromatherapy improved sleep quality versus control (SMD = -0.83; 95% CI: -1.19 to -0.48; I² = 53.5%), where lower PSQI indicates better sleep. Most trials used lavender (Lavandula angustifolia) or damask rose (Rosa damascena) in clinical settings or among participants with insomnia. Certainty is limited by few trials, heterogeneity, and risk of bias. Larger, well-designed randomized trials with standardized dosing, adequate blinding, and longer follow-up are needed.