Conference Coverage

Metabolite levels might help differentiate schizophrenia, bipolar



ORLANDO – Profiling metabolites found in the plasma could be a way to get an earlier handle on how a person’s mental illness will progress, researchers said the annual congress of the Schizophrenia International Research Society.

Dr. Helena Joaquim, University of SãoPaolo Thomas R. Collins/MDedge News

Dr. Helena Joaquim

Investigators at the University of São Paulo found that certain substances – such as phospholipids and sphingolipids – were found in differing levels at the time of a first episode of psychosis, allowing them to accurately identify bipolar disorder or schizophrenia or healthy controls 87% of the time.

The findings suggest a way to help get patients more targeted treatment earlier in their disease course, said Helena Joaquim, MD, PhD, a postdoctoral fellow in the university’s psychiatry department.

“The levels of these metabolites can be a biomarker for psychosis, as well as a diagnostic marker for schizophrenia and bipolar disorder, aiding clinical practice,” the researchers wrote in a poster presentation.

At the time of a first episode of psychosis, the actual diagnosis can be difficult to pinpoint, making the illness more difficult to treat. Since lipid metabolism is altered in neuropsychiatric diseases, the researchers turned to the metabolite levels of patients to pin down a specific diagnosis sooner.

They collected plasma from 28 schizophrenia patients, 27 bipolar patients, and 30 healthy controls. They looked specifically at acylcarnitines, phospholipids, lysophospholipids and sphingolipids. They found that phospholipids were elevated in schizophrenia patients, compared with controls, and even more elevated in patients with bipolar disorder. A similar pattern was seen with lysophospholipids. Sphingolipids were found at lower levels in schizophrenia and elevated in bipolar disorder, compared with controls.

Levels of those three metabolites allowed researchers 87.1% of the time to correctly identify patients as a healthy control or as having schizophrenia or bipolar disorder. Acylcarnitines were not found to be differentiated between schizophrenia and bipolar disorder, the researchers found.

The most interesting part of their efforts so far, Dr. Joaquim said, was a shotgun analysis, an untargeted approach in which about 186 metabolites were measured and plotted on a graph. The compounds have not yet all been identified, but researchers found that levels of these substances were clustered in conspicuous ways.

“It seems like the negative schizophrenia patients are more like the depressive bipolar, and the positive symptoms are more like manic bipolar,” Dr. Joaquim said.

Once refined, these metabolite levels could be a way not only to differentiate schizophrenia patients and bipolar patients, but also to predict severity and directionality of their disorders. For example, looking at metabolite levels might help determine whether schizophrenia patients are more likely to be troubled by positive symptoms, such as hallucinations.

“We have to look back,” Dr. Joaquim said, “and try to identify those metabolites that are the most different between the groups.”

Dr. Joaquim reported no relevant disclosures.

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