Eye- A Strong Indicator of PTSD

A person's pupils can reveal if they have suffered a traumatic experience in the past. Post-traumatic stress disorder pr PTSD causes reduced pupil constriction to stimulus indicating reduced parasympathetic arousal.

Individuals with PTSD also showed a greater pupil dilation to both happy and threatening stimulus. There is a generalized hyperarousal and sensitivity to emotional stimuli in individuals with PTSD.

‘If someone with post-traumatic stress disorder or PTSD is faced with any high-level of emotional stimulation, even if this is positive emotion, it can immediately trigger the threat system. Such individuals show exaggerated response in the pupil of the eyes.’

Post-traumatic stress disorder pr PTSD occurs when a person has experienced any kind of trauma in the past that can be physical or emotional. PTSD can leave a person with greater sensitivity, or hyperarousal to everyday events and the inability to relax.

The research, led by Dr Aimee McKinnon at Cardiff University and published in the journal Biological Psychology, looked for traces of these traumatic events in the eyes of patients who were suffering from PTSD by measuring the pupil of the eye while participants were shown threatening images such as vicious animals or weapons, as well as other images that showed neutral events, or even pleasant images.

The response of people with PTSD was different to other people, including people who had been traumatized but did not have PTSD.

At first the pupil failed to show the normal sharp constriction that is caused by changes in light level - but then their pupils grew even larger to the emotional stimuli than for the other participants.

Another unexpected result was that pupils of the patients with PTSD not only showed the exaggerated response to threatening stimuli, but also to stimuli that depicted "positive" images, such as exciting sports scenes.

Swansea University's Professor Nicola Gray, who co-authored the paper along with Professor Robert Snowden of Cardiff University, believes this is an important finding.

She said: "This shows that the hyper-response of the pupil is in response to any arousing stimulus, and not just threatening ones. This may allow us to use these positive pictures in therapy, rather than relying upon negative images, that can be quite upsetting to the patient, and therefore make therapy more acceptable and bearable. This idea now needs testing empirically before it is put into clinical practice."

Dr McKinnon, who is now at Oxford University, added: "These findings allow us to understand that people with PTSD are automatically primed for threat and fear responses in any uncertain emotional context, and to consider what a burden this must be to them in everyday life.

"It also suggests that it is important for us to recognize that, in therapy, it is not just the fear-based stimuli that need deliberately re-appraising.

"If someone with PTSD is faced with any high-level of emotional stimulation, even if this is positive emotion, it can immediately trigger the threat system. Clinicians need to understand this impact of positive stimuli in order to support their service-users overcome the significant challenges they face."

Source: Eurekalert