This woman was misdiagnosed with bipolar disorder. It turns out she has a rare autoimmune disease instead

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.