Journalist Susannah Cahalan was nearly institutionalized for acute schizophrenia before brilliant neurologists discovered rogue antibodies systematically attacking her NMDA brain…

When a psychiatric crisis has a neurological cause

In anti-NMDA receptor encephalitis, the immune system makes antibodies that interfere with NMDA receptors—protein “receivers” on brain cells that help them communicate. The antibodies can cause many of these receptors to be pulled off the cell surface, disrupting signaling involved in memory, behavior, movement, and awareness. The result can look psychiatric at first, even as the illness develops into a broader brain disorder.

Symptoms often unfold over days or weeks. A person may become confused, paranoid, or unable to sleep, then develop problems with speech, seizures, unusual movements, or unstable heart rate and blood pressure. That progression matters: a sudden change in mental state accompanied by new neurological symptoms calls for a search beyond a primary psychiatric diagnosis.

Why the diagnosis can be missed

The condition is rare, and early symptoms overlap with more familiar psychiatric illnesses. Routine brain scans may not show an obvious abnormality, so clinicians may need to consider the pattern of symptoms and test spinal fluid or blood for antibodies. Finding antibodies in spinal fluid is especially useful; no single symptom alone establishes the diagnosis.

Journalist Susannah Cahalan’s illness became a well-known account of that diagnostic challenge. After an abrupt and frightening change in her behavior and cognition, neurologist Souhel Najjar recognized that a neurological illness might explain what had been treated as a psychiatric crisis. Testing identified anti-NMDA receptor encephalitis, giving her doctors a specific target for treatment.

Treatment addresses the immune attack

Care generally aims to reduce the harmful immune response. Depending on the case, doctors may use steroids, intravenous immune treatments, or plasma exchange, which filters antibodies from the blood. If a tumor is triggering the immune reaction, removing it can also be important. Recovery may be slow because the brain needs time to regain normal function after the attack subsides.

The practical lesson is not that psychosis is usually autoimmune. It is that a rapidly changing psychiatric picture—especially one joined by seizures, movement problems, or confusion—can be a clue to an illness that needs neurological testing and immune treatment.