When 28-year-old Sara Halter was hospitalised for four months she had no idea what lay ahead of her. But countless surgeries and traumatic procedures later as the high-dependency unit became her home, she started having terrifying dreams and intrusive thoughts.

Post-traumatic stress disorder, more widely known as PTSD, is more commonly associated with experiences such as military combat or physical assault, but it can strike after any major trauma. Symptoms of PTSD include intrusive thoughts of the event, nightmares or flashbacks and increased arousal, which can cause sleep difficulties, outbursts of anger and difficulty concentrating.

According to EMDR developer, Dr Francine Shapiro, however, PTSD can also be caused by less dramatic life experiences, too, such as negative childhood memories. She explains PTSD as a series of “unprocessed memories” which control the self as a result of whatever negative incident has occurred, thus disrupting the normal processing system of the brain.

This is where EMDR comes in – the technique that more than 40,000 practitioners have been trained in worldwide since Dr Shapiro developed it in 1989. Relying not on talk therapy or medications, EMDR uses a patient’s own rhythmic eye movements to serve as a distraction to the traumatic events, gradually shifting these repressed, negative thoughts into more neutral or pleasant ones. The goal is to help the patient mentally revisit the traumatic event while concentrating on the movement of the therapist’s finger, thereby helping to “process distressing memories and flashbacks so their influence over your mind is reduced”, according to NHS Choices.

“People describe that the memories become less vivid and more distant, that they seem further in the past and harder to focus on,” Chris Lee, a psychologist and EMDR practitioner at Murdoch University in Australia, is reported to have said. He says that making eye movements during recall may compete with the space for recollection in the mind, which causes the memory to be less intense when recalled again.

A 2011 study in the Journal of Anxiety Disorders found that patients with PTSD who went through a proper session of EMDR reported a significant reduction in their levels of distress, compared with those who went through the same session but kept their eyes closed.

According to the American Psychiatric Association (APA), EMDR is effective for treating both acute and chronic PTSD. In 2011, the Ministry of Defence awarded a three-year contract to offer the treatment for those suffering from PTSD in the army and in America, the Department of Veterans Affairs and the Department of Defense jointly issued clinical practical guidelines which “strongly recommended” EMDR for the treatment of PTSD, too. In the UK EMDR is recommended as a treatment of choice for PTSD by the National Institute of Clinical Excellence (NICE). In 2014 the World Health Organisation (WHO) also recognised EMDR for the treatment of PTSD in adults, adolescents and children.

“Research shows that 84 to 100% of single trauma victims do not experience post-traumatic stress after three 90-minute therapy sessions using EMDR”, Dr Shapiro is reported to have said.

It certainly worked for Sara who, after a couple of sessions of EMDR, found that she gradually stopped thinking about everything that was happening to her and managed to get through the rest of her time in hospital free of the negative thoughts that had been plaguing her. “It really did help me!”, she says.