Doctors discouraged patients with the mystery illness from participating in social media, saying Facebook and YouTube helped facilitate its spread. Flickr via Creative Commons

(Reuters) - Students whose mysterious twitches drew a national spotlight will accept their high school diplomas on Sunday, with most of them back to normal after a controversial diagnosis that the actions were caused by attention from social and news media.

A total of 20 patients - almost all of them girls enrolled at Le Roy Junior/Senior High School - first began exhibiting involuntary movements in October 2011 in this working class town about 50 miles east of Buffalo.

Doctors and state health department officials made the quick but controversial diagnoses of conversion disorder, in which psychological stress causes patients to suffer physical symptoms, and mass psychogenic illness, in which members of a tight-knit group subconsciously copy behavior.

Doctors determined the attention from social media and mainstream media aggravated the problem, and discouraged patients from participating in either. The result, doctors say, is that most of the patients shed the Tourette-like symptoms and returned to a normal life in time for high school graduation on Sunday.

The vindication for us is that the patients are better. They've got their lives back, said Dr. Laszlo Mechtler, who treated 15 of the girls at Dent Neurologic Institute, one of the nation's largest neurology clinics. He said his patients were 80 to 90 percent cured.

As the problem spiraled in the tiny community, celebrity doctors like Dr. Drew Pinsky hosted some of the girls on national television, others girls appeared regularly on local television and in print media with headlines about their mystery illness. The girls posted updates on their seemingly bizarre condition to Facebook and videos of their symptoms to YouTube.

We noticed that the kids who were not in the media were getting better; the kids who were in the media were still very symptomatic, Mechtler said.

One thing we've learned is how social media and mainstream media can worsen the symptoms, he said. The mass hysteria was really fueled by the national media, social media - all this promoted the worsening of symptoms by putting these people at the national forefront.

The patients included one confirmed case of Tourette Syndrome, which Mechtler said could have set the tone for the jerking motions.

The lone adult among the 20 patients is Margery Fitzsimmons, 37, whose friend's teenage daughter was one of the original affected teenagers. She wholeheartedly embraces the conversion disorder diagnosis, and said that it is possible the teen's symptoms may have played into her own over time.

She said learning to deal with stress is one reason she has improved.

My life has gotten back to normal, said Fitzsimmons, who returned to work in February and is now again able to play with her young daughter.

When it got really bad I would measure my progress by how often I didn't have any tics. Now I go a couple of weeks and you would never know I was ill at all, Fitzsimmons said.

After the first case was logged in October, the number of patients soon grew to 12, then 14, then 20 in little more than four months.

Critics including environmental activist Erin Brockovich scoffed at the psychological diagnosis, pressing instead a theory that the tics were caused by environmental contamination from a nearby site of a 1970s train derailment and chemical spill.

But testing at and around the school by the state and the school district ruled out environmental factors, latent side-effects from drugs or vaccines, trauma or genetic factors. School administrators last week released the results of a second environmental test, in which no pollutants were found to explain the students' illness.

The psychological diagnosis was a hard sell to parents of the students whose suburban lives were suddenly turned upside down.

Fitzsimmons said while she agrees with Mechtler's diagnosis, she understands the difficulty other patients' have accepting it.

Because it's considered a psychological diagnosis, they think psychological issues mean they're crazy, she said. I just never understood how connected the mind and body actually are.

(Editing by Barbara Goldberg, Greg McCune and Jackie Frank)