Simon Lauder reported this story on Tuesday, May 14, 2013 12:42:00

EMILY BOURKE: The accidental discovery that anti-inflammatory drugs can help treat mental illness has opened up a new field of research which experts are calling a "paradigm shift".



A mental health conference in Melbourne has heard that clinical trials of anti-inflammatory medicines, including aspirin, have significantly reduced the symptoms of depression, bipolar disorder and schizophrenia.



Professor of Psychiatry at the University of Melbourne, Brian Dean, says the discovery has opened up a new way to target proteins in the brain that cause mental illness.



Professor Dean told Simon Lauder the new weapon against mental illness was discovered by accident, when anti-inflammatory drugs were being used to treat a skin condition.



BRIAN DEAN: The first suggestion that anti-inflammatories might be useful in depression came out of the use of some new drugs that target inflammatory pathways in people with psoriasis.



But what this study found which is really exciting was that in treatment resistant depression, these drugs are used to treat inflammation and skin diseases which are associated with inflammation actually did act as antidepressants.



SIMON LAUDER: So it's a bit of an accidental discovery.



BRIAN DEAN: It is. Most of the treatments in psychiatry have been discovered accidentally, so this fits perfectly. What our work has done here, just to carry on from there, is actually explain why these drugs are likely to be working.



So these drugs target a particular protein in the brain called tumour necrosis factor-alpha, and when we looked at the levels of various tumour necrosis factor ulcers in the brains of people with depression, what our data showed was one of these forms was four and a half times higher in the brains of people with depression than it was in control brain.



Now these drugs that we've been talking about actually block that particular protein.



SIMON LAUDER: So the drugs that target inflammation can also block the proteins that cause mental illness?



BRIAN DEAN: That's what we think, but what that tells us is that if the pharmaceutical industry can get better and better drugs that are more selective at targeting TNF in the brain, because the drugs we have at the moment don't go in the brain very well, they could be a whole new way of treating depression.



SIMON LAUDER: What is the range of mental illnesses that you think might be treatable by anti-inflammatories?



BRIAN DEAN: It's quite interesting because there's been a lot of work done by a clinician called Michael Berk in Geelong. He's shown that if you target these pathways, you can actually have good outcomes in schizophrenia, in bipolar disorder and depression.



There's studies that show if you give someone with schizophrenia aspirin in addition to their existing anti-psychotic drug treatment, they do better. So I think this is a whole new playing field. We really don't know how far this will extend.



What our work is doing again is explaining in schizophrenia why aspirin has worked because we've now shown that the pathways that aspirin targeted are affected in the brains of people with schizophrenia.



So we're beginning to understand the changes in the target sites for these drugs in the brains of people with psychiatric illness, and as we understand more and more about the changes in those pathways, we should be able to make better and better drugs to target the site we need to get at to get the maximum decrease in psychiatric symptoms with the minimum side effect.



SIMON LAUDER: How exciting is this discovery?



BRIAN DEAN: For us it's very exciting because normally when your work, as we do in human brain, and the molecular structure of human brain, you really don't have an understanding of what the pathways you're working on might do.



But because of all the interest in inflammatory diseases in the periphery, we really know how these pathways in the brain work and so we can plan experiments that will do exactly what you said, it will allow us to eventually discover the cause of these changes and when we discover the cause of these changes, we'll discover the cause of psychiatric symptoms in some people with depression and some people with schizophrenia.



SIMON LAUDER: Are anti-inflammatories being used in treatments at the moment?



BRIAN DEAN: They're not, no. I think the important thing here is all the studies that have been done at present are proof of principle studies. They've shown that the concept works. We still don't have the drugs that allow us to get this really strong, therapeutic benefit in the absence of any unwanted side effects.



We still don't have drugs that really get into the brain really effectively and then target these systems. So that's work that all has to be done, but hopefully this work that we're doing and clinicians are doing with these proof of principle studies will get the pharmaceutical industry to focus on these areas of the brain and start making compounds that do target where we want to go to very effectively.



EMILY BOURKE: That's Professor of Psychiatry at the University of Melbourne, Brian Dean, speaking to Simon Lauder.