What has been learned about psychosis as a result of brain scanning research?

Professor Philip McGuire: Brain scanning has been fantastically useful in mental health in terms of understanding what causes psychiatric symptoms, and psychiatric problems.

So until the advent of brain scanning, it was very difficult to relate what one saw clinically with what was happening in the brain. There was a lot of theoretical guessing about how changes in the brain might cause psychiatric problems, but there wasn’t really a lot of evidence, and the only way to study it was in experimental animals, and that’s not the same as studying it in living people.

The real value of brain scanning is that it allows you to study in human beings who are often the only species who have these kind of symptoms, like hallucinations and things like that. Rats and monkeys don’t really experience these, as far as we know. It’s really the only way to study these kind of phenomena, and in the last 10 or 20 years, we’ve learned an awful lot about the basis of psychiatric problems from these kind of studies, so we know now, what changes in the brain, what parts of the brain seem to be involved in feeling anxiety, feeling depression, experiencing hallucinations, being paranoid. We know which parts of the brain are involved, we know how the chemistry of the brain changes in relation to these problems, and how the structure of the brain changes.

So this is incredibly valuable not just in terms of understanding what’s happening in mental health, but also in terms of devising better treatments in the future, because up until now the treatments that we have for common mental health disorders have really been discovered by trial and error, or by accident. They’ve not really been devised on the basis of research knowledge. So whereas in say cardiology, understanding how the heart works allows you to figure out clever ways of treating heart disease, we haven’t really been able to do that up until now in mental health.

For example in psychosis, we know that the structure of the brain is significantly altered, the function of many parts of the brain is altered and the chemistry of the brain is significantly altered.

So that’s potentially very useful information because it suggests that there’s a possibility of preventing, of intervening and changing these problems before they lead to illnesses.