A relatively new class of autoimmune diseases that affect the brain is making psychiatrists rethink some diagnoses.
Though rare, patients with autoimmune encephalitis often present with psychiatric symptoms, and that can lead to misdiagnosis with a mental illness instead, says Dr. Chris Hahn, a neurologist at the Cumming School of Medicine at the University of Calgary.
That’s what happened to Nora Scott of High River, Alta., a town about 70 kilometres south of Calgary.
Before her medical odyssey began in the fall of 2017, Scott says, “Everything was going well.”
But then she started having a hard time falling asleep. “It’s kinda like my mind was always going,” she told John Chipman of CBC’s audio documentary unit.
Scott had to take a break from her job in quality assurance at a local manufacturing plant. Stuck at home, Scott says she fixated on cleaning up her house.
Her partner, Chris Johnson, says he could tell this wasn’t an ordinary decluttering spree.
“I would come home from work and there’d be post-its all over the house, over pictures and everything with prices on it, trying to sell things off.”
Scott displayed other out-of-character behaviours as well, like planning several trips and other lavish spending — patterns that can also be present for people experiencing psychosis due to a mental illness.
Eventually Johnson got her to South Health Campus hospital in Calgary, where Scott was admitted to the psychiatry ward for 30 days.
By the end of that stay she was diagnosed with bipolar disorder.
But it would take another four years and a second lengthy hospital stay before it was discovered that Scott in fact had a rare autoimmune disease called anti-NMDA receptor encephalitis, first discovered in 2007.
As Hahn explains, autoimmune disease is a broad category of conditions where the body’s immune system goes into overdrive and begins attacking itself instead of outside threats like disease and infection.
With various forms of autoimmune encephalitis, it’s the brain that’s under immune attack, often targeting areas that affect mood and perception, in a sense, mimicking a mental disorder.
While anti-NMDA receptor encephalitis can be fatal if untreated, in rare cases it can go into remission on its own, says Hahn, which is why Scott or patients like her can appear to be getting better. And if they’re on mood-stabilizing drugs at the time, it can reinforce a psychiatric misdiagnosis.
Chris Johnson says that at the time of his partner’s diagnosis with bipolar disorder, the hospital staff were preparing him for some pretty tough scenarios.
“They had me meeting with social workers and everything, telling me that my life would change forever and she couldn’t be left home alone, and not trusted with any bills or cards or anything.”
When Nora Scott needed to be hospitalized a second time in November, 2021, she’d become confused and disoriented at work. Her memory of her second incident is a complete blackout.
“I was in the High River Hospital and woke up and it was January,” she said. “So I lost over a month of time.”
That kind of confusion she experienced, as well as the loss of bodily control that her partner observed, aren’t typical of bipolar disorder.
This time Scott was treated on a psychiatry unit at Calgary’s Rockyview Hospital. It was the holiday season, and a newer member of the psychiatry team, Dr. Jadah Johnson, was on duty.
Dr. Johnson says the head nurse was concerned that Scott was getting sicker and sicker.
Dr. Johnson noted that Scott had unusual symptoms for bipolar disorder, and the psychiatrist suggested to the hospital’s neurology unit that she may actually have anti-NMDA receptor encephalitis.
The unit had already considered and ruled out that diagnosis, so Dr. Johnson initially let it go.
Scott, however, wasn’t responding to treatment. So Dr. Johnson went back to the neurology unit again, pushing her colleagues to reconsider her alternate diagnosis.
“It didn’t feel good to go back and say, ‘I really think it’s this,’ and be told like, essentially, ‘you’re a junior idiot,’ like, go away. But, I think I have a healthy dose of not caring what people think.”
Dr. Johnson drew Scott’s blood, and insisted the lab immediately test it for anti-NMDA receptor encephalitis.
The results came back positive. A second, even more reliable, spinal fluid test confirmed it as well.
Patient reconnects with doctor who made her life-saving diagnosis in emotional video call
Recovery Alberta is the government agency responsible for mental health care in the province. A written statement provided to CBC said, in part, that autoimmune encephalitis is a complex condition that can be challenging to diagnose, but that “clinicians in Alberta have access to provincial clinical guidance and specialist consultation to support the assessment and diagnosis of complex conditions, including autoimmune encephalitis.”
It added that it couldn’t comment on individual patient care or earlier clinical decisions.
Dr. Chris Hahn is a member of Scott’s current medical team, but was not involved in her initial treatment.
However, the challenge with her case and others like it led Hahn to spearhead efforts to develop a set of national guidelines to help identify autoimmune encephalitis, which were released in 2024.
Still, he stresses that it’s rare to be misdiagnosed with a mental illness when autoimmune encephalitis is the root cause of psychosis.
A study published in the Lancet medical journal this month says a person is 1,500 times more likely to have a psychotic episode from, for example, young-adult onset psychosis associated with mental illness than from anti-NMDA receptor encephalitis.
Dr. Jai Shah an associate professor of psychiatry at McGill University in Montreal who is also a psychiatrist and researcher at McGill-affiliated hospital Douglas Mental Health University Institute, says episodes of psychosis can have a range of root causes, but that autoimmune origins have only come to be better understood over the past decade or so.
Unfortunately, says Hahn, there’s still a stigma around mental health conditions. “And then you read about autoimmune encephalitis … a condition that’s treatable or sometimes curable. There are [unaccredited private] labs who will do this testing in a fashion that is not up to standard and people will get false positives.”
Shah points out it’s wrong to assume that a diagnosis with autoimmune encephalitis is good news while mental illness is bad.
“We’re trying to avoid this dichotomy, where we present the autoimmune form as treatable and optimistic and hopeful, and the other one — the more common one as not — because that’s not the case.”
And, he points out, people can get better from — or learn to manage — mental illness and go on to live meaningful lives.
“This has been shown over and over and over again in … studies from here and [other countries] that people get better with typical-form psychosis, provided that they get best-practice care and treatment,” said Shah.
Four years following the judgement call that led to Scott’s diagnosis, she and Dr. Johnson spoke for the first time.
“I can honestly say that I did it for your kids,” the doctor told her during a recent video call.
“I heard that you had two kids at home and I was just like ‘I can’t in good conscience have you get sicker on my watch.’”
