Characterization of Olfactory Perception in Post-Traumatic Stress Disorder

NCT06494306 — Unknown, 40 participants, Hospices Civils de Lyon

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Registry	NCT06494306, acronym TRAUMODO
Status	Unknown
Study type	Observational
Enrollment	40 (Estimated)
Sponsor	Hospices Civils de Lyon (Other)
Conditions	Post Traumatic Stress Disorder
Interventions	European Test of Olfactory Capabilities (ETOC), Standardized Hedonicity Test, Questionnaires, Odor / trauma association questionnaire (Behavioral)
Dates	start 2024-08-26 (estimated), primary completion 2026-08-25 (estimated), completion 2026-08-25 (estimated), first posted 2024-07-10, last updated 2024-07-10
Locations	1 site in France

-Summary

The core symptoms of post-traumatic stress disorder (PTSD) include flash backs, intrusive pictures and thoughts related to the traumatic event, hyperalertness, avoidance of traumatic relevant environmental triggers and emotional dysregulation. Some studies suggest that PTSD is also associated with impaired olfactory perception, which seems quite intuitive regarding the close anatomical-functional connections between olfactory and emotional circuits. Furthermore, some studies reported that olfactory stimuli can trigger flashbacks in subjects with PTSD. However, up to know available data is scarce and heterogeneous concerning that topic. The goal of the study is to determine the olfactory phenotype of subjects with PTSD. More precisely, this project aims at filling the above mentioned gap by systematically assessing the olfactory perception of subjects with PTSD along five dimensions: olfactory identity, hedonic value, familiarity, desirability and edibility. As a secondary goal, the relative weight of olfaction compared to the other senses in the relived memories of subjects with PTSD will be assessed.

The investigators here hypothesize a global impairment in olfactory processing (intensity, hedonicity, familiarity and edibility judgments) in PTSD subjects, compared with healthy subjects.

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+Arms and interventions

Arm	Type	Interventions	Description
Patients with PTSD		Behavioral: European Test of Olfactory Capabilities (ETOC); Behavioral: Standardized Hedonicity Test; Behavioral: Questionnaires; Behavioral: Odor / trauma association questionnaire	They are outpatients receiving psychological and medical treatment in the clinical department connected to the inclusion site
Control group		Behavioral: European Test of Olfactory Capabilities (ETOC); Behavioral: Standardized Hedonicity Test	Data from subjects without PTSD included in a previous study

European Test of Olfactory Capabilities (ETOC) (Behavioral): Investigators will collect the ETOC score in patient of both arms
Standardized Hedonicity Test (Behavioral): To smell 20 odorant solutions and for each odor and evaluate it along five dimensions: familiarity, hedonicity, edibility, desire to smell again, perceived intensity). Each dimension is assessed with a Likert scale (from 1 (not at all) to 9 (extremely))
Questionnaires (Behavioral): Patients with PTSD will have the following questionnaires : PTSD Checklist for Diagnostic and Statistical Manual (DSM)-V (PCL-5), Peri-trauma Dissociation Experience Questionnaire (PDEQ), Patient Health Questionnaire-9 (PHQ9), Snaith-Hamilton Pleasure Scale (SHAPS), Childhood Trauma Questionnaire (CTQ) and Apathy Evaluation Scale (AES)
Odor / trauma association questionnaire (Behavioral): Patients with PTSD will have Odor / trauma association questionnaire

+Outcome measures

Primary outcomes

Standardized Hedonicity Test score [at inclusion]: Results obtained in patients will be compared to those obtained in control group

Secondary outcomes

Effects of potential moderators on odor judgement [at inclusion]: Analysis of covariance (ANCOVA) to determine the effect of different moderators (age, gender, type of trauma, time elapsed since trauma, type of treatment received, symptom intensity) on olfactory perception
Evaluation of sensory impressions of memories evoked by certain odors. [at inclusion]: Sensory impressions: Nature and frequency of sensory descriptions associated with odor-evoked memories
Evaluation of emotional valence of memories evoked by certain odors. [at inclusion]: Language analysis: Use of Natural Language Processing (NLP) techniques to assess the emotional valence of odor-evoked memories and recurrent themes in oral responses concerning evoked memories. Analysis of the association of trauma-related odors with the 5 senses

+Eligibility

Sex: All, ages: 18 Years to 50 Years

Inclusion Criteria:

* Age between 18 to 50
* Subjects with PTSD

Exclusion Criteria:

* Patients with a neurological history such as stroke, head trauma (e.g. exposure to explosions, sports injury…), neurodegenerative disease…
* Any psychiatric condition except PTSD and major depressive disorder
* Current or recent use of psychotropic drugs that may affect olfactory function.
* Any current or remitted addictive disorder.
* Pregnancy and breast-feeding women

+Locations (1)

Facility	City	Country	Status
Auvergne-Rhône-Alpes Regional Center for Psychotrauma	Lyon	France

+Investigators

VIGNAUD Philippe, MD, PhD, Principal investigator, Auvergne-Rhône-Alpes Regional Center for Psychotrauma