Olfactory Training and Aromatherapy for Treating Depressive Symptomatology: A Scoping Review

Abstract

Background

Repeated exposure to odorants through olfactory training (OT) and aromatherapy (AT) represents a noninvasive approach for psychological well-being.

Objective

This scoping review investigated how OT/AT can be used to reduce depressive symptoms, summarized intervention characteristics reported in the literature, and pointed out gaps in the literature.

Methods

A scoping review of the literature published between 2000 and 2026 was conducted using a broad search across PubMed, CINAHL, Scopus, and PsycINFO based on inclusion/exclusion criteria on June 17, 2025, and April 13, 2026. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Scoping Reviews guidelines, 29 peer-reviewed interventional studies examining depressive symptomatology outcomes were synthesized.

Results

Most studies (e.g., 22/29) demonstrated improvements in depressive symptomatology (Cohen's d = −0.90 to 1.56; mean Cohen's d = 0.41); however, these effects were not consistently greater than control conditions, as several studies reported only within-group improvements. Results varied likely due to protocol differences (i.e., OT/AT sessions per day/week, odorant types, total intervention durations, measurement tools). Assessing adherence to OT/AT was challenging due to incomplete reporting across studies.

Conclusions

The OT/AT are simple, noninvasive, and relatively affordable interventions for reducing depressive symptoms in several vulnerable populations, except in clinically diagnosed depressive outpatients with moderate symptom severity. The OT/AT aligns with holistic nursing principles by integrating the sensory and emotional components to improve mental health and overall well-being. There is a lack of methodological standardization and inconsistency in monitoring adherence to OT/AT; thus, more rigorous randomized controlled trials are needed to examine its therapeutic benefit.

Impact

This scoping review contributes to future nursing research priorities and provides evidence for integrating OT/AT into holistic nursing practice.