Schizophrenia is a mental illness that affects roughly 24 million people a year, according to World Health Organization statistics.

Researchers know that the disorder runs in families, which points to a hereditary factor, and have also found evidence that it is characterized by abnormalities in the brain’s white matter.

But finding exactly where in the white matter is no easy feat. The most common brain-imaging method, Diffusion Tensor Imaging (DTI), works by mapping the spread of water molecules in cells. The snag is that pathways in white matter are so tightly packed together that getting a precise reading about where a problem is occurring is not possible using this technique.

Now, Harvard Medical School researchers are using a different set of tools to get a more complete picture of this part of the brain.

"The DTI approach was suggesting abnormality but it was non-specific, so couldn’t be sure if it was inside or outside the neuron," says Dost Ongur, senior author of a study published Sept. 15 in the journal Biological Psychiatry. "Now with our work, we can say where that abnormality is."

The results of their research may lead to more targeted treatments and different approaches to making white matter healthier.

The study pinpointed where the abnormalities that characterize schizophrenia are coming from using magnetic resonance spectroscopy, which measures brain chemical levels, and magnetization transfer imaging, which senses changes in myelin throughout the white matter.

"Myelin insulates the neurons and prevents electrical leakage from inside to outside," says Ongur. If there is a problem in the myelin, "that would cause abnormal information processing," he says, "and the connection between neurons in different parts of the brain would suffer."

Their results suggest that the abnormalities happen in both the long projections of neurons called axons, whose primary function is to transmit signals from neuron to neuron, and the myelin. If the axon is an electric wire, the myelin is the plastic covering. Both are important in transmitting information and, in schizophrenia, both appear to function abnormally.

brain image schizophrenia

Biological Psychiatry

Brain scan images showing the marker used to identify changes in white matter in the prefrontal cortex. Courtesy Biological Psychiatry.

"We found abnormalities in both locations," says Ongur. "The implication is if you know where the abnormality is, you can focus your treatment intervention at the place where the abnormality is. We know we need to worry about health of neurons and the myelin."

It’s still too early to use this new imaging method as a diagnostic tool. "One concern is people with other psychiatric problems may have similar abnormalities, too. We’re looking at that," says Ongur.

But it can be used to measure the effects of treatment interventions. For schizophrenia, treatment options include antipsychotic medications, but Ongur says there are other approaches, such as cognitive remediation.

"Cognitive remediation uses computer-based cognitive tasks, which force people to use their brain circuitry in a variety of ways," he says. "We’re hoping this would be a creative way to make healthier white matter."