Impact of Event Scale - Revised

The Impact of Event Scale - Revised (IES-R) is a widely used 22-item psychometric instrument designed to measure the current subjective distress associated…

Questions: 22
Duration: 10 min
Original title: IES-R — Impact of Event Scale – Revised
Adaptation: Impact of Event Scale - Revised
Authors: Weiss, D. S. & Marmar, C. R.
Created: 1997

The Impact of Event Scale - Revised (IES-R) is a widely used 22-item psychometric instrument designed to measure the current subjective distress associated with a specific traumatic event. Developed by Weiss and Marmar to align with the evolving diagnostic understanding of post-traumatic stress, this revised version builds upon the original IES by adding a crucial hyperarousal subscale alongside the established intrusion and avoidance dimensions. By explicitly anchoring the patient's symptom reporting to a designated index event, it allows clinicians to clearly isolate trauma-specific reactions from general distress.

In clinical practice, the IES-R provides a robust, validated framework for recognizing post-traumatic symptoms during the intake phase. Because it evaluates symptom frequency and intensity over the past seven days, it is highly sensitive to clinical change, making it an excellent tool for monitoring treatment response throughout therapy. Whether assessing common post-traumatic reactions after a recent accident or evaluating chronic distress years after an assault, the IES-R gives practitioners a reliable metric to complement their clinical formulation and guide targeted interventions.

Example result

Fictitious result, computed from a sample set of answers.

Overall score

41/ 88

A 22-item self-report questionnaire measuring subjective distress experienced over the past 7 days in connection with a specific traumatic event. It assesses three symptom dimensions of post-traumatic stress disorder: intrusion (re-experiencing), avoidance, and hyperarousal. Used in clinical and research settings with adults exposed to a potentially traumatic event, it provides an overall severity score and three dimensional subscores.

0–23

Low

24–32

Clinically significant

33–36

Probable PTSD

37–88

Extreme

Severe PTSD symptoms — a score ≥ 37 is associated with impaired immune functioning up to 10 years after the event (Kawamura et al., 2001).

généralemixed · general population · n = 999 · Aljaberi et al. (2022)

088

M = 21.06 ± 16.3

cliniquemixed · pathology: PTSD · United States · n = 71 · Rash et al. (2008)

088

M = 45.4 ± 17.8

Scoring

Total sum and sum by subscale, total score from 0 to 88, each item is scored on a 5-point scale (from 0 to 4).

Avoidance

12/ 32

Subscale assessing avoidance symptoms, including efforts to avoid thoughts, feelings, or external reminders related to the trauma. It consists of 8 items.

items 5, 7, 8, 11, 12, 13, 17, 22

032

Intrusion (re-experiencing)

13/ 32

Subscale assessing intrusive symptoms like recurrent thoughts, nightmares, and distressing feelings or imagery related to the traumatic event. It consists of 8 items.

items 1, 2, 3, 6, 9, 14, 16, 20

032

Hyperarousal

16/ 24

Subscale assessing hyperarousal symptoms, such as irritability, anger, difficulty concentrating, hypervigilance, and an exaggerated startle response. It consists of 6 items.

items 4, 10, 15, 18, 19, 21

024

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What the test measures

The IES-R measures the severity of post-traumatic stress symptoms linked to a specific life event across three primary clinical domains. It maps directly onto the core symptom clusters historically associated with PTSD, capturing both the internal experience of the trauma memory and the behavioral efforts to manage it.

Intrusion: Measures the unbidden re-experiencing of the traumatic event, including nightmares, spontaneous intrusive images, and emotional or physical reactivity to reminders.
Avoidance: Captures the conscious and unconscious efforts to evade trauma-related triggers, encompassing behavioral avoidance, deliberate thought suppression, and emotional numbing.
Hyperarousal: Assesses generalized sympathetic nervous system overactivity, including irritability, hypervigilance, exaggerated startle response, and difficulty concentrating or sleeping.

This instrument is validated for use with adults who have experienced a potentially traumatic event, serving as a structured PTSD symptom checklist to gauge current distress levels.

When and why to use it

Clinicians use the IES-R across multiple phases of care to objectify distress, support differential diagnosis, and evaluate the trajectory of recovery. It is particularly valuable when treatment directly targets trauma processing or avoidance behaviors.

Intake and screening: To systematically evaluate the presence and severity of post-traumatic stress, providing a baseline metric before initiating deeper trauma work.
Treatment monitoring: To track symptom fluctuation week by week, helping clinicians and patients see concrete progress when engaging in therapies like EMDR or trauma-focused cognitive behavioral therapy.
Evaluating medical trauma: To assess distress in specialized settings, such as evaluating PTSD symptoms following critical illness or complex medical interventions.
Psychoeducation support: To help patients categorize their diffuse, overwhelming experiences into understandable clusters, making sense of their autonomic nervous system responses to triggers.

While a validated score strongly correlates with diagnostic status, it adds the most clinical value when used to measure symptom severity over time rather than serving as a standalone diagnostic tool.

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The questions

Below is a list of difficulties people sometimes have after stressful life events. Please read each item, and then indicate how distressing each difficulty has been for you DURING THE PAST SEVEN DAYS with respect to the event. How much were you distressed or bothered by these difficulties?
1. Any reminder brought back feelings about it.
Assesses emotional reactivity triggered by external or internal trauma reminders.
- Not at all
- A little bit
- Moderately
- Quite a bit
- Extremely
2. I had trouble staying asleep.
Probes for sleep maintenance difficulties often linked to nocturnal arousal or trauma processing.
- Not at all
- A little bit
- Moderately
- Quite a bit
- Extremely
3. Other things kept making me think about it.
Evaluates the frequency of spontaneous, unbidden cognitive intrusions related to the index event.
- Not at all
- A little bit
- Moderately
- Quite a bit
- Extremely
4. I felt irritable and angry.
Checks for the presence of generalized emotional dysregulation and lowered threshold for frustration.
- Not at all
- A little bit
- Moderately
- Quite a bit
- Extremely
5. I avoided letting myself get upset when I thought about it or was reminded of it.
Captures deliberate emotional suppression and attempts to disconnect from trauma-related affect.
- Not at all
- A little bit
- Moderately
- Quite a bit
- Extremely
6. I thought about it when I didn't mean to.
Measures the degree to which trauma memories intrude upon conscious awareness against the patient's will.
- Not at all
- A little bit
- Moderately
- Quite a bit
- Extremely
7. I felt as if it hadn't happened or it wasn't real.
Assesses dissociative features, specifically derealization and denial surrounding the trauma.
- Not at all
- A little bit
- Moderately
- Quite a bit
- Extremely
8. I stayed away from reminders of it.
Probes for active behavioral avoidance of people, places, or situations associated with the event.
- Not at all
- A little bit
- Moderately
- Quite a bit
- Extremely
9. Pictures of it popped into my mind.
Evaluates the presence of intrusive visual flashbacks or spontaneous distressing imagery.
- Not at all
- A little bit
- Moderately
- Quite a bit
- Extremely
10. I was jumpy and easily startled.
Checks for an exaggerated startle response, a hallmark sign of chronic sympathetic nervous system activation.
- Not at all
- A little bit
- Moderately
- Quite a bit
- Extremely
11. I tried not to think about it.
Measures active cognitive avoidance and deliberate thought suppression strategies.
- Not at all
- A little bit
- Moderately
- Quite a bit
- Extremely
12. I was aware that I still had a lot of feelings about it, but I didn't deal with them.
Assesses the conscious deferral or avoidance of emotional processing.
- Not at all
- A little bit
- Moderately
- Quite a bit
- Extremely
13. My feelings about it were kind of numb.
Probes for emotional numbing, a common protective dissociative mechanism in chronic trauma.
- Not at all
- A little bit
- Moderately
- Quite a bit
- Extremely
14. I felt and acted as if I were back in that situation.
Captures the experience of dissociative re-experiencing or vivid flashbacks where the past feels present.
- Not at all
- A little bit
- Moderately
- Quite a bit
- Extremely
15. I had trouble falling asleep.
Evaluates sleep onset insomnia, frequently associated with pre-sleep hyperarousal and anxiety.
- Not at all
- A little bit
- Moderately
- Quite a bit
- Extremely
16. I had waves of strong feelings about it.
Measures the occurrence of sudden, overwhelming surges of trauma-related emotion.
- Not at all
- A little bit
- Moderately
- Quite a bit
- Extremely
17. I tried to remove it from my memory.
Assesses extreme cognitive avoidance and the desire to actively erase the traumatic memory.
- Not at all
- A little bit
- Moderately
- Quite a bit
- Extremely
18. I had trouble concentrating.
Checks for cognitive impairment and reduced attentional capacity resulting from sustained hyperarousal.
- Not at all
- A little bit
- Moderately
- Quite a bit
- Extremely
19. Reminders of it caused me to have physical reactions, such as sweating, trouble breathing, nausea, or a pounding heart.
Probes for intense somatic distress and physiological reactivity when exposed to trauma cues.
- Not at all
- A little bit
- Moderately
- Quite a bit
- Extremely
20. I had dreams about it.
Evaluates the presence of trauma-related nightmares and sleep disturbance.
- Not at all
- A little bit
- Moderately
- Quite a bit
- Extremely
21. I was watchful and on my guard.
Measures hypervigilance and the chronic scanning of the environment for potential threats.
- Not at all
- A little bit
- Moderately
- Quite a bit
- Extremely
22. I tried not to talk about it.
Captures interpersonal avoidance and the reluctance to verbally disclose or process the event.
- Not at all
- A little bit
- Moderately
- Quite a bit
- Extremely