The hallucinations, delusions and cognitive difficulties experienced by people with schizophrenia are due to widespread damage to the brain’s wiring.

That’s according to research carried about by scientists across the world as part of the ENIGMA consortium and co-lead by NUI Galway.

“It’s almost 40 years since we had the first clues that schizophrenia was associated with changes in the brain structure,” said Professor Gary Donohue, NUIG, a senior author on the study published in Molecular Psychiatry.

“What the ENIGMA consortium has achieved here is to provide definitive proof that these changes are not specific to any one area of the brain, but rather reflect subtle, yet widespread changes throughout the brain.”

“In terms of the idea that schizophrenia might be caused by a mis-wiring of the brain, this study provides unequivocal evidence that this is the case,” said Professor Donohue. “The next step will be to identify the individual genetics variants that lead to the mis-wiring,” Prof Donohue added.

Schizophrenia has been the focus of neuroimaging studies for decades, yet its neurobiology remained only partially understood. The World Health Organisation has described the disease as a leading cause of disability, and more disabling than paraplegia or blindness in 18 to 35 year olds.

The ENIGMA consortium brought together researchers from all over the world to conduct the first large-scale, co-ordinated study of white matter differences in people with schizophrenia.

The researchers examined samples from 4,322 individuals, and that large number allowed for greater power to identify changes across the entire brain than has been possible with previous studies.

The consortium team used a technology called diffusion tensor imaging to show that, in people with schizophrenia, the white matter fibres which connect different brain regions are frayed making communication between different regions ‘sub optimal’. Changes were seen right across the brain.

This is the first conclusive evidence to support the ‘dysconnectivity hypothesis’ which held that schizophrenia may involve abnormal or inefficient communication between brain regions due to disturbances in the pattern of white matter.