Outcome MeasurePTSD

IES-R

Impact of Event Scale – Revised

4 Papers in Blossom

About This Instrument

The Impact of Event Scale – Revised (IES-R) is a 22-item self-report measure designed to assess subjective distress caused by traumatic events. Developed by Daniel Weiss and Charles Marmar as a revision of the original 15-item IES, it evaluates three symptom clusters: intrusion (8 items), avoidance (8 items), and hyperarousal (6 items). Each item is rated on a 5-point scale (0 = not at all, 4 = extremely) over the past seven days, yielding a total score of 0–88. A score of 33 or above suggests probable PTSD. The IES-R is frequently used as a secondary outcome in psychedelic-assisted therapy trials targeting PTSD and trauma-related conditions. It has strong internal consistency (α > 0.90 for all subscales) and correlates well with clinician-rated PTSD measures like the CAPS.

Clinical Thresholds

088
Subclinical
Score 0–23
Clinical concern
Score 24–32
Probable PTSD
Score 33–36
Severe
Score 37–88

Outcome Data Across Studies

Reported results for IES-R across 3 studies with quantitative data.

Outcome data across 12 study arm–timepoint observations
SD
The safety and efficacy of ±3,4-methylenedioxymethamphetamine-assisted psychotherapy in subjects with chronic, treatment-resistant posttraumatic stress disorder: the first randomized controlled pilot study
2010Secondary
MDMA-AT(experimental)01244.94.3—
The safety and efficacy of ±3,4-methylenedioxymethamphetamine-assisted psychotherapy in subjects with chronic, treatment-resistant posttraumatic stress disorder: the first randomized controlled pilot study
2010Secondary
MDMA-AT(experimental)41223.75.30.016
The safety and efficacy of ±3,4-methylenedioxymethamphetamine-assisted psychotherapy in subjects with chronic, treatment-resistant posttraumatic stress disorder: the first randomized controlled pilot study
2010Secondary
MDMA-AT(experimental)71218.24.1—
The safety and efficacy of ±3,4-methylenedioxymethamphetamine-assisted psychotherapy in subjects with chronic, treatment-resistant posttraumatic stress disorder: the first randomized controlled pilot study
2010Secondary
MDMA-AT(experimental)601215.05.00.038
The safety and efficacy of ±3,4-methylenedioxymethamphetamine-assisted psychotherapy in subjects with chronic, treatment-resistant posttraumatic stress disorder: the first randomized controlled pilot study
2010Secondary
Placebo + therapy(inactive)0845.15.3—
The safety and efficacy of ±3,4-methylenedioxymethamphetamine-assisted psychotherapy in subjects with chronic, treatment-resistant posttraumatic stress disorder: the first randomized controlled pilot study
2010Secondary
Placebo + therapy(inactive)4846.06.50.016
The safety and efficacy of ±3,4-methylenedioxymethamphetamine-assisted psychotherapy in subjects with chronic, treatment-resistant posttraumatic stress disorder: the first randomized controlled pilot study
2010Secondary
Placebo + therapy(inactive)7838.35.0—
The safety and efficacy of ±3,4-methylenedioxymethamphetamine-assisted psychotherapy in subjects with chronic, treatment-resistant posttraumatic stress disorder: the first randomized controlled pilot study
2010Secondary
Placebo + therapy(inactive)60832.66.10.038
Durability of improvement in post-traumatic stress disorder symptoms and absence of harmful effects or drug dependency after 3,4-methylenedioxymethamphetamine-assisted psychotherapy: a prospective long-term follow-up study
2012Secondary
MDMA-AT(experimental)611619.819.5—
Durability of improvement in post-traumatic stress disorder symptoms and absence of harmful effects or drug dependency after 3,4-methylenedioxymethamphetamine-assisted psychotherapy: a prospective long-term follow-up study
2012Secondary
MDMA-AT(experimental)13821622.121.8—

Papers Using IES-R

Open Accessindividual

Preliminary evidence for the importance of therapeutic alliance in MDMA-assisted psychotherapy for posttraumatic stress disorder

This analysis of a clinical trial (n=22) examines the role of therapeutic alliance in MDMA-assisted psychotherapy (MDMA-AP) for treating chronic PTSD. It reports that after controlling for baseline PTSD severity, a strong therapeutic alliance at the mid and late stages of treatment (sessions 4 and 9) significantly predicts lower clinician-assessed and self-reported PTSD severity post-treatment.

Published
Journal
European Journal of Psychotraumatology
Authors
Zeifman, R. J., Kettner, H., Ross, S., Weiss, B., Mithoefer, M. C., Mithoefer, A. T., Wagner, A. C.
Open Accessindividual

Efficacy of Intravenous Ketamine for Treatment of Chronic Posttraumatic Stress Disorder

This randomised, double-blind, active placebo-controlled crossover proof-of-concept study (n=41) compared the efficacy of ketamine (35mg/70kg) and midazolam (3.15mg/70kg) for the treatment of patients with depressive symptoms associated with chronic PTSD. They found a rapid reduction in symptom severity following intravenous ketamine infusion.

Published
Journal
JAMA Psychiatry
Authors
Feder, A., Parides, M. K., Murrough, J. W.
Open Accessindividual

Durability of improvement in post-traumatic stress disorder symptoms and absence of harmful effects or drug dependency after 3,4-methylenedioxymethamphetamine-assisted psychotherapy: a prospective long-term follow-up study

In a prospective long-term follow‑up (mean 45.4 months) of the first MDMA‑assisted psychotherapy trial for chronic, treatment‑resistant PTSD (n=19; 16 CAPS completers), symptom reductions observed at study exit were largely maintained (mean CAPS 24.6 vs 23.7; p=0.91) though two participants relapsed. No participants reported harm or evidence of drug dependency, suggesting durable clinical benefit and a favourable safety profile.

Published
Journal
Journal of Psychopharmacology
Authors
Mithoefer, M. C., Wagner, M. T., Mithoefer, A. T., Jerome, L., Martin, S. F., Yazar-Klosinski, B., Michel, Y., Brewerton, T. D., Doblin, R.
Open Accessindividual

The safety and efficacy of ±3,4-methylenedioxymethamphetamine-assisted psychotherapy in subjects with chronic, treatment-resistant posttraumatic stress disorder: the first randomized controlled pilot study

In the first randomised controlled pilot trial, MDMA-assisted psychotherapy produced significantly greater reductions in Clinician-Administered PTSD Scale scores than placebo in 20 patients with chronic, treatment‑resistant post‑traumatic stress disorder (83% response vs 25%). There were no drug‑related serious adverse events, adverse neurocognitive effects or clinically significant blood pressure increases, suggesting MDMA may be a safe and effective adjunct to psychotherapy in refractory PTSD.

Published
Journal
Journal of Psychopharmacology
Authors
Mithoefer, M. C., Wagner, M. T., Mithoefer, A. T., Jerome, L., Doblin, R.

Quick Facts

Full Name
Impact of Event Scale – Revised
Domain
PTSD
Papers Indexed
4
Score Range
0–88
Interpretation
Lower = better
Unit
points
All Measures