Paris Jackson, Prince Harry use EMDR to treat PTSD. Here's what that is.

At one point, simply admitting to battling issues like depression was seen as radical. But as the stigma surrounding mental illness continues to fall away, many celebrities are now opening about the treatment that's helped them manage their conditions. Recently, the discussion has centered on a lesser-known therapy known as Eye Movement Desensitization and Reprocessing or EMDR. This week, Paris Jackson mentioned the technique on Red Table Talk, telling Willow Smith she's used it as a way to treat post-traumatic stress disorder (PTSD) that she developed after years of relentless paparazzi.

Earlier this summer, Prince Harry described using the technique to work through his own PTSD in the wake of his mother's death. In his new documentary The Me You Can't See, the Royal tells the EMDR therapist that "London is a trigger" and leads to feelings that he's being "hunted." The therapist asks him to think of the emotions he feels upon landing there while tapping his shoulders with opposite arms.

Jackson did not go into as much detail about her EMDR experience but said that it's been helping in treating her "gnarly" social anxiety, as well as the "audio hallucinations" she hears (such as phantom camera clicks) that lead to intense paranoia. "[I've] been going to therapy for a lot of things, that included, and I've started EMDR," says Jackson. "I'll hear a trash bag rustling and I'll flinch and panic... I think it's just standard PTSD."

Video: Paris Jackson admits paparazzi triggered PTSD

So what exactly is EMDR and how does it work? Yahoo Life spoke with three experts in the field to help unpack the technique and what its potential benefits are. Here's what you need to know.

The technique dates back to the late 1980s

EMDR was the brainchild of the late Dr. Francine Shapiro, a psychiatrist based in California who — while walking in a park one day — realized that her own eye movements helped "decrease the negative emotion associated with her own distressing memories," according to the EMDR Institute. Shapiro began testing the technique on volunteers and soon found that engaging the brain in both remembering trauma and moving the eyes helped to alleviate some of the pain connected with it.

EMDR helps patients undergo a controlled "reprocessing" of a traumatic event

Justin C. Baker, clinical director of the Suicide and Trauma Reduction Initiative for Veterans (STRIVE) and assistant professor-research in the Department of Psychiatry & Behavioral Health at the Ohio State University Wexner Medical Center, says the technique works by "having the patient visualize and retell their story of the event; while the patient visualizes and narrates the event, bilateral eye movement (or some other form of bilateral stimulation like tapping, or playing of audio tones), are facilitated by the therapist."

Baker says that the pairing of eye movement and retelling may retrain the brain to store the trauma in a different way. "The leading hypothesis here is that a dual awareness of the environment helps to facilitate a reprocessing of the traumatic event similar to possibly how rapid eye movement takes place during REM sleep phases," Baker tells Yahoo Life. "The goal of treatment within EMDR is to help patients process unprocessed traumatic memories, and decrease current symptoms of PTSD."

Many experts were skeptical of the technique at first, and some remain so

Nancy Smyth, a professor at the University at Buffalo School of Social Work, has been using EMDR on patients since 1994. Even after receiving training from Shapiro, who invented the technique, she was still dubious about how it worked. "I have to admit, I wasn't quite sure what to make of it initially," Smyth tells Yahoo Life. "But at that time [Shapiro] sort of challenged us to say, 'Is it okay for people change in ways that we don't always understand?'"

Smyth says the first of her patients who tried it saw immediate results. "She came back a week later and I said, 'So, what do you think?' And she said, 'Well, it was amazing. All of a sudden I can now take showers without panic attacks,'" Smyth recalls. "Honestly, I was dumbfounded — and I found myself thinking maybe it's not okay with me if people change in ways I can't understand. I tell that mostly to explain that I was not a convert, I was skeptical. There has always been a little bit of me every time I use it that is surprised."

Smyth has found great success employing the treatment with trauma patients, including 9/11 survivors, but says that some areas of the science community have still yet to fully embrace the concept. Some critics, owing to how quickly it works and how simple it appears, have even referred to it as "pseudoscience."

The effectiveness of EMDR has been proven in multiple studies

Dr. Roger Solomon, a senior trainer at the EMDR Institute as well as its program director, does consultations on the technique with high-profile clients such as the U.S. Senate and NASA. He says that a collective of 44 randomized controlled studies (the gold standard for research) has proven the effectiveness of EMDR for treating PTSD. Those reading about EMDR for the first time, he says, should be aware that it is "evidence-based" and "can be effectively applied to a wide variety of problems."

"There is also strong evidence that the eye movement utilized in EMDR therapy, in and of itself, has a therapeutic effect," Solomon tells Yahoo Life. "Further, there are many more studies and case series that have been published showing EMDR therapy to be effective with a wide variety of disorders, including treatment of the trauma of disease and injury such as cardio problems and cancer."

All three experts commend Jackson and Prince Harry for speaking out about their experience

"I've actually said for decades that what EMDR needs are some celebrities to come forward," says Smyth. Solomon agrees. "It is a very positive thing that Prince Harry and other celebrities are coming forward and talking about treatment. Prince Harry had a lot of courage to share how EMDR therapy helped him deal with the death of this mother. This normalizes getting the help one needs and reduces the stigma that many people feel. Thank you, Prince Harry and other celebrities for your courage."

Baker is equally grateful and hopes that their coming forward may motivate others to seek treatment. "I believe that anytime we can help de-stigmatize mental health, and promote current evidence-based treatments, is a win both for the field of mental health and those in need of treatment," says Baker. "When people see celebrities, athletes and other prominent figures express [this] in an honest fashion, it has an immediate normalizing effect. People get to see that successful people need help, too."

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