The Role of Expectations in the Development of Intrusive Memories

Study Overview
=================
Brief Summary
-----------------
In the experimental study, the well-established trauma film paradigm will be used to investigate the impact of expectations on the development of intrusive memories as a hallmark symptom of PTSD.

Detailed Description
-----------------
The study aims to examine the influence of different expectations on the development of intrusive memories by using a well-established experimental paradigm - the trauma film paradigm. In healthy volunteers, intrusion-like symptoms are to be induced with an analogue stressor, i.e., aversive film clip footage (trauma film). After viewing this so-called trauma film, the expectations of intrusions during the following week are manipulated by assigning participants randomly to three different groups. In the first group, negative expectations are induced (experimental group 1), the second group is exposed to positive expectations (experimental group 2) and a third group does not face any kind of manipulation of their expectations (control group). Participants are asked to report occurring intrusions in a diary during the following week and are invited to a subsequent cued laboratory inquiry at follow-up.

Official Title
-----------------
The Role of Expectations in the Development of Intrusive Memories: An Experimental Approach Using the Trauma Film Paradigm

Conditions
-----------------
Posttraumatic Stress Disorder

Intervention / Treatment
-----------------
* Behavioral: Positive Expectation Manipulation
* Behavioral: Negative Expectation Manipulation


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: healthy volunteers fluent in German language Exclusion Criteria: history of traumatic experiences (LEC-5) presence of a mental disorder (SCID-I according to DSM-IV) cut-off in depression screening (PHQ-9) current suicidal thoughts/behavior or non-suicidal self-injury behavior (C-SSRS) medical history of heart disease or epilepsy history of fainting work experience in the medical field (e.g., nurses, paramedics, etc.) visual impairment students of psychology and medicine

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Participants are assigned to one of three arms in parallel for the duration of the study.
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Negative Expectations<br>Expectations on the severity and frequency of intrusions are increased while expectations on the controllability of intrusions are decreased. | Behavioral: Negative Expectation Manipulation<br>* Participants are watching a video tape of a trauma expert who provides selective information on the development of intrusive memories. This video tape aims to increase negative expectations.<br>|
| Experimental: Positive Expectations<br>Expectations on the severity and frequency of intrusions are decreased while expectations on the controllability of intrusions are increased. | Behavioral: Positive Expectation Manipulation<br>* Participants are watching a video tape of a trauma expert who provides selective information on the development of intrusive memories. This video tape aims to increase positive expectations.<br>|
| No Intervention: No Expectation Manipulation<br>Expectations on the severity and frequency of intrusions and on the controllability are neither increased nor decreased. | |

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Frequency and severity of intrusive memories: Daily intrusion diary | Participants are asked to complete a pen-and-paper diary 7 days in a row, reporting on intrusive memories in reference to the trauma film. They are asked to state the number of intrusions per day; each day of the diary is labeled and split into three sections (morning, afternoon, evening), and they are asked to mark in a box in the appropriate section when they experienced an intrusion. For each intrusion, they indicate the quality of the intrusion (image, thought or both), the intensity of and distress caused by the intrusion both on a scale ranging from 0 (not at all) to 10 (extremely), the content of the intrusion, and the situation in which the intrusion occurred. Intrusive memory frequency across 7 days are calculated, whilst higher sum scores represent more intrusions. Severity of intrusions are calculated by combining the average score of the intensity and distress scale across all intrusions, whilst higher values indicate higher intensity/distress of reported intrusions. | Record of any intrusive memories of the trauma film content for Days 1 to 7 after the experimental manipulation. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Distress caused by the trauma film: Impact of Event Scale-Revised (IES-R) | Participants are asked to respond 22 items in reference to the trauma film (e.g., Pictures about the film popped into my mind.) by indicating how often each reaction occurred during the past seven days with respect to the film they watched last week. Items are rated on a 4-point-Likert-scale ranging from 0 (not at all), 1 (rare), 3 (sometimes) to 5 (often). The IES-R consists of three subscales: intrusion, hyperarousal, and avoidance. The total score (sum score for the total scale comprising the sum scores of all three subscales) is calculated ranging from 0 to 110 with higher values represent a worse outcome, i.e., higher total distress due to the trauma film in the past week. In addition, the sum score for the intrusion subscale is separately calculated ranging from 0 to 35 (Items 1, 3, 6, 9, 14, 16, 20) with higher values represent more intrusions due to the trauma film in the past week. | At the follow-up measurement (7 days after the experimental manipulation). | 
| Laboratory assessment of intrusive memories: Intrusion Provocation Task (IPT) | In the Intrusion Provocation Task (IPT), participants are presented with a ten-second long neutral still image from each of the film clips. Immediately afterwards for the next two minutes, they are allowed to think freely and report intrusions by raising a finger. The investigator counts how often the participant lifts his finger in the two minutes. The IPT intrusion score is calculated by the total frequency of intrusions, whilst higher values represent more intrusions. | At the follow-up measurement (7 days after the experimental manipulation). |