Is there more than one type of schizophrenia? Brain scans now suggest there are at least two different kinds of the psychiatric disorder, a finding that backs up what many have long suspected and may one day lead to more specialised treatments for specific sets of symptoms.
About 1 per cent of people have schizophrenia, and those with it can have a range of symptoms, from hallucinations and delusions to problems with social interactions and cognitive performance. Not only do symptoms vary for each person, but so do their responses to drug treatments. Antipsychotic drugs clear only some people’s hallucinations, for example. And there are no good treatments for relieving the social and cognitive effects of the disorder.
This diverse range of symptoms and responses has led many people to wonder whether there are distinct types of schizophrenia. But so far this hasn’t worked very well – subcategories based on symptoms were after they were found to be unreliable. “There was no stability in symptoms over time,” says of Ludwig Maximilian University of Munich in Germany.
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Koutsouleris and his colleagues are on the hunt for ways to define subtypes of schizophrenia using biology, not symptoms. The idea is that biological factors should provide a more objective insight into a person’s condition, and be more informative about how to treat it.
Two groups
The team looked at MRI brain scans from 71 people with schizophrenia and 74 people without it. This revealed anatomical differences between people who had the disorder and those who didn’t. Further analysis revealed two subgroups within those with schizophrenia.
The two schizophrenia groups had differences in symptoms. For example, the group characterised by a smaller than usual volume in the brain’s frontal regions had had schizophrenia for less time, and experienced more hallucinations.
The other group had more severe symptoms, differences in more regions of their brains, and they had experienced more blunted emotions and social withdrawal, over longer periods of time.
Better diagnosis
The team can’t be sure that this is evidence for two distinct forms of schizophrenia. It is possible that simply having schizophrenia – and taking antipsychotic drugs – for longer could explain the difference. “We know antipsychotics have effects on brain volume over time,” says at the University of Oxford.
Tunbridge does also think that there are likely to be different subtypes of schizophrenia. “My hunch would be to go down the genetic route,” she says. Schizophrenia can run in families, and many gene variants that might predispose a person to the disorder have already been identified. Some of these seem to overlap with bipolar disorder and autism-like behaviour, further bolstering the idea that we should ditch symptom-based diagnosis for many mental health conditions and move toward biological markers, says Tunbridge.
Koutsouleris and his colleagues hope their method could eventually be used to predict which treatments might work for a person. The team is now sifting through nearly 3000 more brain scans to identify other variations in brain anatomy. “The two subtypes we’ve identified could just be the first layer,” says Koutsouleris. “If we increase the sample size, we may find that each splits into two or three.”
Schizophrenia Bulletin
