BOSTON (CBS) – New research findings, published in the American Journal of Psychiatry this month, report a disconnect between traditional diagnoses for psychotic disorders and biological signatures found in a patient’s brain.
“We need better labels that are based on objective, measurable, biological data, not just simply symptom based data,” said Dr. Matcheri Keshavan, a principal investigator in the study and Vice-Chair of Public Psychiatry with Beth Israel Deaconess Medical Center.
A traditional method for diagnosing a psychotic illness like schizophrenia or bi-polar disorder involves evaluating a patient’s symptoms, such as hallucinations or hearing voices. Experts do not always agree with each other on a person’s diagnosis based on those symptoms.
“If you want to distinguish between one kind of cancer versus another kind of cancer, a biopsy will tell you,” Keshavan told WBZ-TV. “We don’t have a reliable way of distinguishing between psychiatric disorders.”
Keshavan leads the Boston group of researchers, one of five teams across the country, who studied more than 2,000 participants over about 8 years. Roughly 800 patients diagnosed with a psychotic disease, 1,000 of their family members, and 200 healthy people were screened under the Bipolar Schizophrenia Network for Intermediate Phenotypes (B-SNIP) Consortium.
The project identified three categories that more precisely classify disorders based on a patient’s underlying brain biology, without regard for their symptoms.
The research team began by looking at two “biological markers” in each participant. Using electroencephalography (EEG) and cognitive tests, they discovered three clusters or “biotypes.” Brain scans were then used to make further inferences about the three categories.
In the first group, Biotype 1, participants showed lower brain wave response in the EEGs and demonstrated poor cognition. Their brains also have the most evidence of brain tissue loss, or gray matter, throughout the brain.
By contrast, Biotype 2 showed much higher brain wave responses, but also demonstrated cognitive impairments. Their brains showed slight damage, particularly in the frontal region.
The final group, Biotype 3, showed fairly normal EEG results and cognitive skills. Though some participants in this category may have been diagnosed with a disorder in the past, this group is for all intents and purposes, the control group.
“Even though we’ve known in the past few decades that these disorders are primarily brain disorders, people still believe they are due to mental weakness or a personal weakness of some kind,” said Keshavan. He believes studies like this underscore the point that these are biological diseases and not a moral failing.
The implications of looking for biological differences could be huge. Beyond just furthering the effort to reduce the stigma of mental illness, studies like this could provide scientists molecules to target for new treatments, better predict treatment response, rule out those who aren’t truly ill, and might one day point to a cause for psychotic disorders.
B-SNIP is funded by the National Institute of Mental Health (NIMH). Dr. Keshavan’s team at Beth Israel will be working for at least the next five years and hope to replicate their results and expand on their findings.