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Blood Tests for Diagnosis of Schizophrenia and Depression?: Page 4 of 4

Blood Tests for Diagnosis of Schizophrenia and Depression?: Page 4 of 4

Test benefits

Both Renshaw and Williams believe the test will have benefits for primary care and psychiatry. “The technology will become a standard of care in both primary care and in psychiatry,” Renshaw predicted.

“Too many people with depression are not diagnosed using standard clinical assessment measures,” he said. “Moreover, there is also a real possibility that the Ridge biological marker technology will be useful in optimizing treatment selection by assessing 4 different marker domains (neurotrophic, metabolic, immune, and endocrine).”

Williams added that in the company’s main market research, psychiatrists reported up to 30% of their depressed patients are difficult to manage, do not comply with their treatment plan, and have work and family issues.

“By having a biological indication of depression, patients and their families have an improved understanding of the condition as a medical one, which reduces the stigma associated with mental health disorders and leads to an improvement in treatment compliance. We have several case studies citing examples of the test results being used by psychiatrists to improve communications with their patients and ultimately improve outcomes,” she said.

A simple blood test can also greatly assist primary care physicians in distinguishing true depression from overlying symptoms, particularly in situations of chronic pain or where patients cannot “self-report.”

“Market research,” she added, “also suggests that up to 50% of MDD cases are missed at the primary care level, leading to delayed treatment and other unnecessary, costly diagnostic evaluations.”

Simplified blood test

At the Japanese Society of Biological Psychiatry Conference in Tokyo last May, researchers reported devising a test that measures the concentration of phosphoric acid in the blood as an indicator of major depression.

Noriyuki Kawamura, MD, PhD, of the Gaien Mental Clinic in Tokyo, and Yoshiaki Ohashi, PhD, board member and chief security officer at Human Metabolome Technologies, Inc (HMT), a spinoff biotechnology company from Keio University, led the research project. This particular project was conducted independently from Keio University.

HMT’s “patented metabolomics techniques using Capillary Electrophoresis-Mass Spectrometry (CE-MS) enabled simultaneous measurement of more than 500 metabolites in blood plasma,” said Ohashi, who is also leader of biological research at HMT and a part-time lecturer at Keio University.

The simultaneous and comprehensive measurement of metabolites in plasma from depressed subjects (n = 34, diagnosed at the National Center of Neurology and Psychiatry in Kodaira, Tokyo) and demographically matched nondepressed subjects (n = 38) resulted in the identification of the new depression biomarker, ethanolamine phosphate (EAP), according to Ohashi. The study showed that patients with depression had lower plasma concentrations of EAP.

The marker (EAP), Ohashi added, is sensitive enough and accurate enough to diagnose major depression (true positive rate, 82%; true negative rate, 95%).

“We are developing a reagent to gauge the level of EAP within minutes,” Ohashi said. “We expect to complete the development of reagent in a year and to seek health ministry approval after conducting clinical trials.”

To conduct clinical trials of the depression test, HMT is attempting to recruit more than 1000 participants from the Gaien Mental Clinic and another research clinic in Tsuruoka, Japan. A journal article on the biomarker research also is being submitted.

Speaking about benefits of the test, Ohashi told Psychiatric Times, “the guidelines for diagnosing depression include elements that are difficult to capture objectively; for example, ‘insomnia or hypersomnia nearly every day,’ ‘loss of energy,’ and so on. What should doctors do if patients falsely report their symptoms? On the other hand, some depressed patients might underplay their symptoms because of the stigma of disclosure and perhaps because of the fear of receiving antidepressants. We have identified a biomarker of major depression that correlates with diagnosis by an experienced psychiatrist. This is very good news for general practitioners to whom many depression patients go at the first visit.”

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References

References

1. Holmes E, Tsang TM, Huang JT, et al. Metabolic profiling of CSF: evidence that early intervention may impact on disease progression and outcome in schizophrenia. PLoS Med. 2006;3:e327.
2. Schwarz E, Izmailov R, Spain M, et al. Validation of a blood-based laboratory test to aid in the confirmation of a diagnosis of schizophrenia. Biomark Insights. 2010;5:39-47.
3. Schwarz E, Guest PC, Rahmoune H, et al. Identification of a biological signature for schizophrenia in serum. Mol Psychiatry. 2011 Apr 12; [Epub ahead of print].
4. Ridge Diagnostics. Improving the Diagnosis of Major Depressive Disorder: a New Multi-Analyte Biomarker Panel and MDDScore. October 18, 2010.

 
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