Schizophrenia symptoms tend to appear in adolescence or young adulthood. And while there are some early warning signs which can identify a person at high risk for the disorder, there is no way to definitively diagnose it until the first psychotic episode.
Now, an international research team led by neuroscientists at Massachusetts Institute of Technology (MIT) have identified a specific brain activity pattern that correlates with the development of schizophrenia. This brain activity could potentially be used as a marker to help diagnose the disease earlier.
“You can consider this pattern to be a risk factor. If we use these types of brain measurements, then maybe we can predict a little bit better who will end up developing psychosis, and that may also help tailor interventions,” says lead author Guusje Collin, a visiting scientist at MIT’s McGovern Institute for Brain Research.
Before a person with schizophrenia experiences a psychotic episode — characterized by sudden changes in behavior and a loss of touch with reality — patients can experience milder symptoms such as disordered thinking.
Disordered thinking can involve jumping from topic to topic at random, or giving answers unrelated to the original question. Previous studies have shown that about 25 percent of people who experience these early symptoms go on to develop schizophrenia.
The study, published in the journal Molecular Psychiatry, was conducted at the Shanghai Mental Health Center due to the huge volume of patients who visit the hospital annually. This allowed a large enough sample of people at high risk of developing schizophrenia.
Overall, the researchers followed 158 people ages 13 to 34 who were identified as high-risk because they had experienced early symptoms. The team also included 93 control subjects wit no risk factors.
At the beginning of the study, the researchers used functional magnetic resonance imaging (fMRI) to measure a type of brain activity involving “resting state networks.” Resting state networks consist of brain regions that preferentially connect with and communicate with each other when the brain is not performing any particular cognitive task.
“We were interested in looking at the intrinsic functional architecture of the brain to see if we could detect early aberrant brain connectivity or networks in individuals who are in the clinically high-risk phase of the disorder,” says principal investigator Susan Whitfield-Gabrieli, a visiting scientist at the McGovern Institute and a professor of psychology at Northeastern University in Boston.
One year after the initial scans, 23 of the high-risk patients had experienced a psychotic episode and were diagnosed with schizophrenia. In those patients’ scans, taken before their diagnosis, the researchers identified a specific pattern of activity that was different from the healthy control subjects and the at-risk subjects who had not developed psychosis.
For example, in most people, a brain region known as the superior temporal gyrus, which is involved in auditory processing, is highly connected to brain regions involved in sensory perception and motor control. However, in patients who developed psychosis, the superior temporal gyrus became more connected to limbic regions, which are involved in processing emotions. This could help explain why patients with schizophrenia usually experience auditory hallucinations, the researchers say.
In addition, high-risk patients who did not go on to develop psychosis showed network connectivity nearly identical to that of the healthy subjects.
This type of distinctive brain activity could be useful as an early indicator of schizophrenia, especially since it may be seen in even younger patients. The team is currently conducting similar research with younger at-risk populations, including children with a family history of schizophrenia.
“That really gets at the heart of how we can translate this clinically, because we can get in earlier and earlier to identify aberrant networks in the hopes that we can do earlier interventions, and possibly even prevent psychiatric disorders,” Whitfield-Gabrieli says.
She and her colleagues are now testing early interventions, such as cognitive behavioral therapy and neural feedback, that could help mitigate the symptoms of schizophrenia. The neural feedback approach involves training patients to use mindfulness meditation to reduce activity in the superior temporal gyrus, which tends to increase before and during auditory hallucinations.
The researchers are still following the patients in the current study and analyzing data on the brain’s white matter connections to see if they yield any additional differences that could also serve as early indicators of disease.
The study also involved Jijun Wang of the Shanghai Mental Health Center; William Stone and the late Larry Seidman, both of Beth Israel Deaconess Medical Center in Boston; and Martha Shenton of Brigham and Women’s Hospital in Boston.