The hallucinations and delusions in a subset of children with psychosis may be linked to overactive antibodies, according to a new study published in the journal Biological Psychiatry. The findings add to a growing body of research that supports an “immune hypothesis” for certain types of psychosis.
“The antibodies we have detected in children having a first episode of acute psychosis suggest there is a distinct subgroup for whom autoimmunity plays a role in their illness,” said Dr. Fabienne Brilot, senior author on the article and Head of the Neuroimmunology Group at The Children’s Hospital at Westmead in Sydney.
In a healthy person, antibodies protect the body against bacteria, viruses, and other invaders. But when the antibodies begin to attack healthy cells, an automimmune disorder can develop.
In the new study, researchers detected antibodies to the dopamine D2 receptor or the N-methyl-D-aspartate (NMDA) glutamate receptor in a subgroup of children experiencing their first episode of psychosis. Both are key neural signaling proteins that have previously been implicated in psychosis. These antibodies were not found in healthy children.
For decades, psychiatrists have administered drugs that stimulate dopamine D2 receptors or block NMDA receptors. Sometimes these drugs produce side effects that resemble psychosis, including changes in perception, delusions, and disorganization of thought processes. The current study suggests that people may develop antibodies that affect the brain in ways that are similar to these psychosis-producing drugs.
“This study adds fuel to the growing discussions about the importance of antibodies targeting neural proteins and it raises many important questions for the field. Do these antibodies simply function like drugs in the brain or do they ‘attack’ and damage nerve cells in some ways?” questioned Dr. John Krystal, Editor of Biological Psychiatry.
“Also, are these antibodies producing symptoms in everyone or do they function as a probe of an underlying, perhaps genetic, vulnerability for psychosis?”
Importantly, work is advancing rapidly in this area. Not too long ago, scientists first identified anti-NMDA receptor encephalitis, a disease characterized by inflammation of the brain. It is known to trigger acute psychiatric symptoms including psychosis, and it is commonly misdiagnosed as schizophrenia or bipolar disorder. It is far more treatable, however, as it is essentially brain inflammation caused by antibodies that attack the brain’s NMDA receptors.
“The data from this study suggests that better interventions are possible, providing hope that major disability can be prevented for the subset of children experiencing acute psychosis with antibodies,” Brilot added.
“These findings also contribute significantly to an emerging acceptance in the field of the involvement of autoimmune antibodies in neurological diseases. Combined, these investigations are providing a better understanding of the biology of psychiatric and neurological diseases, as well as pointing to novel treatment approaches for children with these debilitating illnesses.”