Perception of Stressful Social Stimuli After Trauma Exposure.

Study Overview
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Brief Summary
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Post-traumatic stress disorder is associated with altered processing of sensory stimuli. The clinical phenotype PTSD has predominantly been described for the visual and auditory sensory modalities. However, PTSD symptoms such as intrusive memories are often evoked by olfactory and tactile cues in the environment. Moreover, little is known about whether aberrant responses to social olfactory and tactile stimuli are also present in a subclinical population.The purpose of this study is to compare trauma-exposed subjects (e.g. childhood maltreatment) with non-exposed controls in the processing of olfactory and tactile stimuli. This sensory characterizations hold potential to identify potential biomarkers for the course of trauma-related disorders and to inform trauma therapies focusing on sensory integration.

Official Title
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Abnormal Processing of Stressful Social Stimuli After Trauma Exposure, in Particular After Childhood Maltreatment.

Conditions
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Post-traumatic Stress Disorder

Intervention / Treatment
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* Behavioral: Processing of social olfactory and tactile stimuli


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Signed informed consent Subjects that have experienced a traumatic event that meets the DSM-5 criteria Exclusion Criteria: Schizophrenia, schizoaffective or other psychotic disorder Neurological disorders Psychotropic medication Subjects suffering from a respiratory tract infection or other respiratory disorder known to affect olfactory functioning at investigator's discretion Subjects with anosmia or other previous primary olfactory dysfunction (olfactory threshold score using the Sniffin' Sticks ≤ 5) Dermatitis of the extremities or other skin disorders that affect the skin sensitivity of the extremities

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Individuals exposed to an intentional/non-intentional trauma<br> | Behavioral: Processing of social olfactory and tactile stimuli<br>* Processing of social olfactory and tactile stimuli in trauma-exposed individuals and controls is examined using functional magnetic resonance imaging.<br>|
| Healthy controls without trauma-exposure<br> | Behavioral: Processing of social olfactory and tactile stimuli<br>* Processing of social olfactory and tactile stimuli in trauma-exposed individuals and controls is examined using functional magnetic resonance imaging.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Emotion recognition ratings obtained during a forced-choice emotional face recognition task with stimuli of varying intensities (neutral to fearful). |  | Ratings will be assessed throughout fMRI scanning over the course of 25 minutes. | 
| Neural substrates of social tactile stimuli processing. | fMRI scanning will be used to measure neural respones to tactile stimuli. | The neural substrates will be assessed througout fMRI scanning over the course of 20 minutes. | 
| Valence ratings of social tactile stimuli. |  | Ratings will be assessed throughout fMRI scanning over the course of 20 minutes. | 
| Neural substrates of social olfactory stimuli processing. |  | The neural substrates will be assessed througout fMRI scanning over the course of 25 minutes. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Oxytocin plasma concentrations. |  | The oxytocin plasma concentrations of all participants will be assessed 15 minutes before fMRI scanning onset.. | 
| Olfactory performance in a n-butanol odor staircase threshold test. | Participants' olfactory performance will be assessed by administering the 'Sniffin' Sticks' test, which measures nasal chemosensory performance based on pen-like odor dispensing devices. | The olfactory threshold of all participants will be assessed in a screening session at least 24 hours prior to fMRI scanning. |