Smyth · British journal of health psychology 2008 · randomized controlled trial · n=25

Expressive writing and post-traumatic stress disorder: effects on trauma symptoms, mood states, and cortisol reactivity.

Cited 188 times in the scientific literature.

Level 2 - randomized trial

Individual randomized controlled trial

PubMed 18230238 · doi:10.1348/135910707X250866 · record verified 2026-08-29

What was done

A randomized controlled trial evaluated the feasibility, safety, and efficacy of an expressive writing intervention in 25 volunteers with a verified diagnosis of PTSD. Participants were randomly assigned to an experimental group (writing about their traumatic experience) or a control group (writing about time management). Outcomes measured at baseline and 3-month follow-up included PTSD severity and symptoms, mood states, and post-traumatic growth; cortisol reactivity to trauma-related stress was assessed post-intervention only.

What was found

The abstract reports no numerical values, confidence intervals, or exact p-values. No changes in PTSD diagnosis or symptom severity were observed between groups. The expressive writing group demonstrated significant improvements in mood states and post-traumatic growth, alongside an attenuation of neuroendocrine (cortisol) reactivity to trauma-related memories.

Why it matters

This trial suggests expressive writing is feasible and safe for individuals with PTSD, showing potential benefits for emotional regulation and physiological stress reactivity despite having no effect on core PTSD symptoms.

Limits

The sample size is very small (N=25). Cortisol reactivity lacked a baseline measurement (post-only). The abstract provides no quantitative data or effect sizes.

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