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Schizophrenia diagnosis may be autoimmune disease

December 19, 2016 in

Brisbane researchers have discovered that as many as three percent of people diagnosed with schizophrenia may actually have an autoimmune disease that can be treated with immunotherapy.

Brisbane Diamantina Health Partners (BDHP), a collaboration of hospitals and medical research institutes, is about to fund a Brisbane-wide study of all young people newly diagnosed with psychosis in an effort to find the causes of schizophrenia, after an initial study found some cases were caused by antibodies attacking the brain.

“We screened all patients coming through to the Royal Brisbane and Women’s Hospital and the Lady Cilento Children’s Hospital and we found that about three percent (four of 116 patients) ended up having this autoimmune encephalitis which was masquerading as what we previously called psychosis or schizophrenia,” said Dr James Scott, a psychiatrist with the Early Psychosis Service at the Royal Brisbane and Women’s Hospital, and an associate professor at the University of Queensland.

It follows the discovery in 2006 of a new cause of encephalitis, which is an inflammation of the brain. Blood tests showed antibodies were attacking what are called N-methyl-D-aspartate (NMDA) receptors in the brain and in some patients, the only symptoms are confusion personality changes and hallucinations and delusions. These people were presenting to psychiatric services for treatment of psychosis, and were often diagnosed with schizophrenia.

The patients actually had an autoimmune disorder, similar to coeliac or thyroid disease, or rheumatoid arthritis. Once diagnosed, rather than being treated with antipsychotic drugs and psychiatric therapy the patients were sent to an immunologist.

“And so the end result was that persons who were treated with immunotherapy did much better,” said Dr Scott.

The symptoms of schizophrenia resolved once those patients were treated with immunosuppressing drugs. If a simple blood test hadn’t been available to identify their autoimmune disease, these people might have been given anti-psychotic drugs that wouldn’t have worked, and might be categorised as having schizophrenia for the rest of their lives.

The recent Brisbane study showed that autoimmune encephalitis is more common than previously thought, responsible for as many as three percent of patients admitted to hospital for treatment of psychosis.  That might not sound like a lot, but it suggests that between 3000 and 11,000 Australians currently diagnosed with schizophrenia could be better treated with autoimmune drugs. It’s a discovery that could save the health system tens of millions of dollars each year, not to mention the indirect economic and social benefits of people returning to normal life.

The NMDA antibody is just one of a number of antibodies linked to autoimmune encephalitis that cause psychosis.

Our group here has made a very important finding that starts to unpack the causes of psychosis,” said Dr Scott. “We have this opportunity now, due to goodwill and collaboration in the partnership through the Brisbane Diamantina Health Partners, to actually bring together a massive coordinated research effort to really inform the medical community about causes and treatments for psychosis.”

There is a stigma attached to schizophrenia that makes it difficult to treat. It’s a disease that’s not well understood, because the brain is so complex and the changes that can cause mental illness so subtle.

“But we are now getting some hard data,” said Dr Scott. “We can measure these antibodies, for instance. We can show people whose psychosis is caused by an autoimmune response that when we give this treatment, these antibodies go down and your mental health gets better. Suddenly, the treatment makes sense to people, and so the treatment is much more likely to be taken.”

That’s important with illnesses such as schizophrenia, which have a high suicide rate. If an autoimmune disease causes a psychosis, anti-psychotic drugs won’t work. If immunosuppressing drugs can better treat even one percent of the nation’s 360,000 schizophrenia cases, hundreds of suicides could be prevented.

The Brisbane Diamantina Health Partners is launching a large study to find the causes of schizophrenia, enlisting every young person newly-diagnosed with psychosis in Brisbane.

“We’re establishing a collaboration with Brisbane’s hospital and medical research institutes such as the Queensland Brain Institute to establish an early psychosis research platform,” says Dr Scott. “So we’re hoping that every patient that comes into our services will participate in having information collected on their clinical status, as well as neuroimaging,  genetics, biological markers, family history, and we’ll follow them over two years.

“At the moment, we lump all psychoses into the same bucket, but as this study has shown, not all psychoses are the same. Some are caused by these antibodies. Others will be caused by other factors. If we can start separating them out, we can provide individualised care and treatment for each individual psychosis.”

The long-term study will also alert health professionals about the potential different causes of psychosis.

“By providing this platform for medical research, Brisbane Health Services will be providing the best possible care in the world for young people with psychosis,” said Dr Scott. Information produced by the study will  be available to other centres. “It’s a chance for us to lead the world.”