Olfactory Training and Emotional State (ENOLFEA)

During the past three decades, researchers have paid particular attention to the study of olfactory disorders in depression. Recent studies have shown that depression is characterized by a change in olfactory and emotional perception resulting in a decrease of the perception of positive stimuli (odors and facial expressions) and an increase in perception of negative stimuli (odors). Moreover, it has also been shown in healthy subjects that the presence of minor depressive symptoms leads to a decreasing of olfactory sensitivity. However, odor discrimination was not impaired in these subjects. This observation suggest the presence of a change in "targeted" olfactory perception in people with depressive symptoms without reporting major depression. In addition, studies in subjects with olfactory disorders (following respiratory tract infections or following Parkinson's disease) have shown an improvement in olfactory function after daily training with odors during 12 weeks.

From all these observations, the hypothesis is that an olfactory training could improve the overall olfactory functioning and the emotional perception of the subjects presenting minor depressive symptoms and of the depressed patients.

Study Overview

• Status: Completed
• Conditions: Depressive Symptoms; Depressive Disorder, Major
• Intervention / Treatment: Other: Sensory training

Detailed Description

Recent studies have shown that depression is characterized by a change in olfactory and emotional perception resulting in a decrease of the perception of positive stimuli (odors and facial expressions) and an increase in perception of negative stimuli (odors). Moreover, it has also been shown in healthy subjects that the presence of minor depressive symptoms leads to a decreasing of olfactory sensitivity. However, odor discrimination was not impaired in these subjects. This observation suggest the presence of a change in "targeted" olfactory perception in people with depressive symptoms without reporting major depression. In addition, studies in subjects with olfactory disorders (following respiratory tract infections or following Parkinson's disease) have shown an improvement in olfactory function after daily training with odors during 12 weeks. Therefore, the hypothesis is that an olfactory training could improve the overall olfactory functioning and the emotional perception of the subjects presenting minor depressive symptoms and of the depressed patients.

The main objective is to study the effect of daily olfactory training on the emotional state and emotional perception of the subject. The effect of the training will be evaluated using three types of evaluations: (1) a clinical evaluation and the psychometric scales, (2) the investigation of the olfactory function and (3) the study of the emotional perception.

The secondary objectives are:

• The identification of olfactory parameters and emotional valences associated with minor depressive symptoms.
• The study of the link between the subjective and objective emotional response on the one hand, and the link between olfactory function, emotional perception and emotional state on the other hand in depressed patients and in individuals with minor depressive symptoms.

• Study Type: Interventional
• Enrollment (Actual): 150
• Phase: Not Applicable

Contacts and Locations

Study Locations

• France
  • Tours, France, 37000
    • University health service, University ,Tours
  • Tours, France, 37032
    • UMR 1253 IBrain, University, Tours
  • Tours, France, 37044
    • University Psychiatric Clinic, University hospital,Tours

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria healthy subjects:

• Without psychiatric history
• QIDS scale score less than or equal to 15
• Affiliation to a social security system
• Able to give his written informed consent

Inclusion Criteria depressed patients:

• With a diagnosis of depressive episode characterized according to the DSM-5 criteria, confirmed by the Mini International Neuropsychiatric Interview (MINI)
• No argument for bipolar disorder or schizophrenia, confirmed by the MINI
• QIDS scale score greater than or equal to 16
• Follow-up in hospitalization and / or ambulatory consultation
• Without comorbidities (alcoholism, eating disorders ...)
• Affiliation to a social security system
• Able to give his written informed consent

Exclusion Criteria healthy subjects and depressed patients:

• Pathology or condition likely to modify their olfactory and / or taste perception
• Allergies with one or more odors, food allergies and / or known anosmias and ageusia
• Legal incapacity and / or circumstances rendering the person incapable of understanding the nature, objectives or consequences of the study

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Other: Sensory training; Sensory (Olfactory or visual) training will be done at home for 12 weeks. The effect of the training will be evaluated using an experimental protocol includes (i) clinical and psychometric evaluations, (ii) the study of olfactory perception using Sniffin' Sticks Test and (iii) the study of the emotional perception using the "subjective" Sense'n Feel method and the "objective" measurement of the spontaneous pupillary dilatation.

Other: Sensory training; 12 weeks sensory training; Other Names: Olfactory or visual training

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from Baseline Olfactory Perception at 3 months	Score obtained with the Sniffin 'Stick test	Baseline (T0), a month and a half (T1.5), 3 months (T3)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Emotional perception measured Sense'n Feel Method	Score obtained with Sense'n Feel Method	Baseline (T0), a month and a half (T1.5), 3 months (T3)
Emotional perception measured with SMI RED-m Scientific device	Observation of spontaneous pupillary dilatation with SMI RED-m Scientific device	Baseline (T0), a month and a half (T1.5), 3 months (T3)
Psychometric scale MINI : Psychiatric disorders exploration	Mini International Neuropsychiatric Interview	Baseline (T0), a month and a half (T1.5), 3 months (T3)
Psychometric scale TAS-20 : alexithymia assessment	Twenty-item toronto Alexithymia Scale (TAS-20)	Baseline (T0), a month and a half (T1.5), 3 months (T3)
Psychometric scale STAI-Y : anxiety assessment	State Trait Anxiety Inventory	Baseline (T0), a month and a half (T1.5), 3 months (T3)
Psychometric scale SHAPS : anhedonia assessment	The Snaith-Hamilton Pleasure Scale	Baseline (T0), a month and a half (T1.5), 3 months (T3)
Psychometric scale QIDS-SR16 : Depression assessment	Quick Inventory of Depressive Symptomatology	Baseline (T0), a month and a half (T1.5), 3 months (T3)

Collaborators and Investigators

• Sponsor: University Hospital, Tours
• Investigators: Study Director: Wissam EL-HAGE, MD-PhD, University Hospital, Tours

Study record dates

Study Major Dates

• Study Start (Actual): August 28, 2018
• Primary Completion (Actual): June 27, 2023
• Study Completion (Actual): June 27, 2023

Study Registration Dates

• First Submitted: July 12, 2018
• First Submitted That Met QC Criteria: July 20, 2018
• First Posted (Actual): July 30, 2018

Study Record Updates

• Last Update Posted (Estimated): December 30, 2025
• Last Update Submitted That Met QC Criteria: December 23, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: Depression; Emotion; Perception; Olfaction; Sensory training
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Mental Disorders; Behavioral Symptoms; Mood Disorders; Sensation Disorders; Depressive Disorder; Olfaction Disorders; Pathological Conditions, Signs and Symptoms; Behavior; Signs and Symptoms; Anosmia; Depression; Depressive Disorder, Major; Musculoskeletal and Neural Physiological Phenomena; Nervous System Physiological Phenomena; Sensation; Smell
• Other Study ID Numbers: PHAO17-WEH/ENOLFEA; 2018-A00653-52 (Other Identifier: IdRCB); 2018.05.02 (Other Identifier: CPP)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No