Time post-trauma

How is time since trauma exposure related to PTSD?

Exposure to at least one trauma is required for a diagnosis of PTSD. The latest version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) determines direct traumas as threatened death, actual or threatened serious injury, or actual or threatened sexual violence. Indirect traumas include witnessing the trauma, or learning that a relative or close friend was exposed to a trauma. Differences in trauma characteristics, including time since exposure, can affect the risk of having PTSD. Personal characteristics such as age and sex also influence risk.

What is the evidence for risk of PTSD at varying time intervals post-trauma exposure?

Moderate quality evidence found the prevalence of PTSD symptoms in patients with a coronavirus infection was around 29%. Rates of PTSD were highest when measured after rather than during outbreaks in patients and the general public, while healthcare workers showed higher rates of PTSD during rather than after outbreaks.

There was a medium-sized effect of increased PTSD symptoms in healthcare workers exposed to critical incidents compared to healthcare workers not exposed to critical incidents. The effect was larger after four weeks post-incident than before four weeks post-incident.

The incidence of PTSD after a flood was around 16%, with incidence highest within six months after the flood. The incidence of PTSD after an earthquake was around 24%, with incidence highest within nine months after the earthquake. There was medium-sized effect of fewer PTSD symptoms in older adults than younger adults following exposure to man-made disasters. The effect was largest up to 6 months after the disaster.

The prevalence of PTSD in people with cancer was around 11%. Rates of PTSD were higher in studies of people with a longer time since cancer diagnosis. For people with spinal cord injury, there was a small association between less PTSD symptoms and more time the injury.

There was a small association between less time after exposure to any trauma in children and adolescents and increased risk of PTSD. For child and adolescent asylum seekers and refugees, the prevalence of PTSD was around 23%, and was higher for those displaced for less than two years than for those displaced for over two years.

There were medium-sized associations between exposure to disasters and PTSD symptoms in youth ≤18 years. These associations were strongest measured at 6-12 months than at <6 months or over 12 months post-disaster.

There was a large effect of more PTSD symptoms in parents of chronically ill children than in parents of healthy children. Rates were lowest in parents of children with longer time since active treatment.

There were no associations between PTSD and time since exposure to mass shootings or road traffic accidents.

August 2021

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Last updated at: 11:16 pm, 11th October 2021
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