Olfactory Training and Emotional State

NCT ID: NCT03605524

Last Updated: 2025-12-30

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 150 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2018-08-28
• Study Completion Date: 2023-06-27

Brief Summary

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.

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.

Conditions

Depressive Symptoms; Depressive Disorder, Major

Keywords

Sensory training; Depression; Olfaction; Emotion; Perception

Study Design

• Allocation Method: NA
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: OTHER
• Blinding Strategy: NONE

Study Groups

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.

Group Type: OTHER

Sensory training

Intervention Type: OTHER

12 weeks sensory training

Interventions

Sensory training

12 weeks sensory training

Intervention Type: OTHER

Other Intervention Names

Olfactory or visual training

Eligibility Criteria

Inclusion Criteria

• 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

• 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

• 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

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 65 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

University Hospital, Tours

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Wissam EL-HAGE, MD-PhD

Role: STUDY_DIRECTOR

University Hospital, Tours

Locations

University health service, University ,Tours

Tours, , France

UMR 1253 IBrain, University, Tours

Tours, , France

University Psychiatric Clinic, University hospital,Tours

Tours, , France

Countries

France

Other Identifiers

2018-A00653-52

Identifier Type: OTHER

Identifier Source: secondary_id

2018.05.02

Identifier Type: OTHER

Identifier Source: secondary_id

PHAO17-WEH/ENOLFEA

Identifier Type: -

Identifier Source: org_study_id