into madness somethings killing me
Her body was attacking her brain
01:20 - Source: CNN/HLN

Something’s Killing Me” airs Sundays at 9 p.m. ET/PT on HLN.

Story highlights

Autoimmune encephalitis is a disease in which the immune system mistakenly attacks the brain

Many cases have been mistaken for mental illnesses, such as schizophrenia

CNN  — 

Emily Gavigan was convinced that a nearby truck was following her. Someone was after her.

She was a sophomore at the University of Scranton in January 2009 when the “bizarre” behavior began, said her father, Bill.

Her parents noticed that she had been rambling, not making any sense. At one point, she called her family and friends to warn them: Something terrible was going to happen to all of them.

“Emily was like a different person. We didn’t know who she was,” Bill Gavigan said. “We had gone from having this daughter who was perfectly normal, happy, vibrant … with a bright future ahead.

“All of a sudden, this all came crashing down.”

Then, one day, Gavigan disappeared.

“We didn’t know where she was for more than 24 hours,” her father said.

She had gotten in her car and driven from Pennsylvania to New Jersey with no money. She went right through toll booths without paying. But she eventually found her way back to her grandparents’ house, still convinced that she was being followed.

Her grandfather peered out the window, looking for something suspicious. But they soon realized there was no one after her.

“I get emotional when I think about it,” said Gavigan’s grandfather Joseph Chiumento.

Her parents showed up and took her to the hospital.