Medical mystery: For decades, she was told she was ‘just anxious.’ A midair incident uncovered the truth.

All her life, Lorri Devlin had been told that the troubling feelings she frequently experienced had a simple cause: She was “just anxious.”

At age 5, Devlin remembers being jolted awake in the middle of the night by the sound of her teeth chattering. Feeling disoriented and that “something was very wrong,” she entered her parents’ bedroom. But when she spoke, the result was gibberish.

One morning at her elementary school in Stoughton, Mass., Devlin said she felt as though her body were buzzing, as a feeling of inexplicable terror rolled up her torso.

Her parents told her it was yet another “attack of nerves.”

“My mother was an anxious person and took it in stride,” recalled Devlin, now 60 years old and living on Cape Cod. “We went to church and prayed a lot. I felt I had to be strong — we’re stoic Yankees — but I was really ashamed.”

Once while playing softball, Devlin, then 12, felt the buzzing again, accompanied by a momentary inability to see or lift her arm. “You were shaking,” a cousin later told her.

At 17, she remembers waking up terrified, then summoning her courage and telling her mother, “I think I need to see somebody.”

She said she vividly remembers her mother’s response. “She was sewing and she looked up and said, ‘You think you need to see a psychiatrist? Go back to bed. There’s nothing wrong with you,’ ” Devlin recalled.

The dismissive response was crushing, but in the 1970s mental illness was often regarded as a shameful character flaw.

Devlin said she learned to live with her feelings, gutting it out through nursing school and two difficult pregnancies.

Her dentist remarked on the six teeth she cracked over several years and a ridge of scar tissue along the inside of her cheek and lip, which she bit during sleep. He, too, blamed a familiar culprit: anxiety.

In her 30s, Devlin decided she was probably suffering from panic attacks and began therapy, which lasted for years. After describing her feelings of detachment, disorientation and terror, the therapist concurred with her self-diagnosis.

The event that would change Devlin’s life occurred in April 2017, as she and her second husband were flying home from a vacation on Captiva Island, Fla.

Midway through the flight, Devlin had been napping when she awoke suddenly, feeling that something was “horribly wrong.” The walls of the plane seemed paper thin, she said, and she felt a rolling terror. The last thing she remembers before losing consciousness was asking her husband for help.

Devlin awoke soon afterward feeling confused and agitated. She lay across the middle and aisle seats, her head in her husband’s lap. Flight attendants crowded around her. Devlin realized that her jeans were wet: She had urinated involuntarily. “I was mortified,” she said.

An hour later, after landing in Providence, paramedics trundled her off to a small community hospital.

In the emergency room, “my husband told the doctor that I had said, ‘Something’s wrong, I’m going to faint,’ before falling back in my seat. After a few seconds my eyes opened and my mouth hung open. I began rocking back and forth violently, staring straight ahead.”

The doctor asked whether she had a fear of flying. He seemed to disregard her answer — she didn’t — and patted her arm, telling her he had once fainted during a flight.

Back home, Devlin decided that she hadn’t fainted. Her discharge papers had listed “seizure vs syncope,” which meant that doctors weren’t sure whether her brief loss of consciousness was due to syncope, also known as fainting.

She thought of all the times in her life she’d experienced something similar: the buzzing, the rolling feeling of terror, the detachment. Devlin compiled a log, then wondered how she — and especially her doctors — could have missed what seemed so glaringly obvious.

A few days later, Devlin saw her internist. “That wasn’t a faint,” she remembers her doctor saying. “You had a seizure.”

Devlin turned to Boston’s Beth Israel Deaconess Medical Center, a Harvard teaching hospital, where she had previously been a patient. Scrolling through the list of specialists, she settled on Bernard S. Chang, chief of the division of epilepsy and clinical neurophysiology.

Chang told Devlin that her history and medical records seemed consistent with temporal lobe epilepsy. More than three million Americans are believed to have epilepsy, a chronic neurological disorder. The in-flight event was probably a grand mal seizure — the dramatic convulsions that are popularly associated with epilepsy. Devlin’s inability to speak or move at other times signified partial or focal seizures.

Seizures are the result of abnormal electrical activity in the brain. Epilepsy can be caused by a head injury, illness or abnormal development; in many cases, Devlin’s included, the cause is unknown. It is common for people with epilepsy to experience strange emotions or sensations. Those with temporal lobe epilepsy may experience auras, which can cause a feeling of foreboding, an odd smell or taste, or a rolling sensation similar to being on a roller coaster.

Anxiety or depression can occur as a result of seizures or as a side effect of drugs to control them.

There is no cure for epilepsy, but in most cases drugs can control seizures.

The brain disorder has long been the subject of myth and stigma, arising in part from its centuries-old association with being “possessed” or demonic. Stigma, Chang said, has contributed to delayed diagnosis. Epilepsy is sometimes misdiagnosed as a psychiatric illness, including schizophrenia.

“We see kids who are diagnosed with [attention-deficit disorder] because they have staring episodes” — a behavior commonly seen in absence seizures.

Delayed diagnosis is not uncommon, Chang said, but a delay of 50 years is.

“It’s easy now in retrospect” to make the diagnosis in Devlin’s case, he added, but other disorders must be ruled out.

“We were convinced enough to start her on medication immediately,” Chang said. Devlin then underwent an MRI to rule out a brain tumor and an EEG, which records electrical activity in the brain. Both tests were normal; a normal EEG in someone with epilepsy is not unusual, neurologists say.

Devlin’s rapid and dramatic reaction to the epilepsy drug clinched the diagnosis.

“I was awed,” said Devlin, who felt transformed within days of starting it.

She no longer bit her lip or the inside of her cheek while she slept. She didn’t wake up with aching muscles. The sense of detachment vanished, along with the buzzing. She felt calm. The only side effect was sleepiness, to which she has adjusted.

“I literally wept with relief at finally having a diagnosis, an intelligent physician, and a drug to manage my symptoms,” she said.

In addition to stigma and denial, Devlin believes that her diagnosis might have been delayed by the time at which her seizures often occurred: during sleep.

The failure to consider epilepsy was particularly striking, given Devlin’s family history.

One of her sisters was diagnosed with temporal lobe epilepsy at age 20. And an aunt experienced staring spells, although she was never given a diagnosis. (Genetics is believed to play a role in the development of some forms of the disorder.)

Devlin said that the diagnosis triggered a wholesale reevaluation of her life.

“It’s overwhelming,” she said, adding “I wonder how my life would have been different” had she not spent decades convinced that she was “just anxious” — and seriously flawed.