Key TakeawaysResearchers have developed a new test—the first of its kind—to accurately predict depression, based on the levels of this protein found in the brain.Experts warn that this kind of test may not be applicable to all patients experiencing depression and can be limiting.More research needs to be done to see how a test on biomarkers can factor into treatment.

Key Takeaways

Researchers have developed a new test—the first of its kind—to accurately predict depression, based on the levels of this protein found in the brain.Experts warn that this kind of test may not be applicable to all patients experiencing depression and can be limiting.More research needs to be done to see how a test on biomarkers can factor into treatment.

Now, researchers have developed a new test—the first of its kind—to accurately predict depression, based on the levels of this protein found in the brain.

How Depression Is Diagnosed

With this assay kit, measuring mBDNF levels could help to diagnose depression and bipolar disorder.

At the same time, increased production of BDNF has also been linked to exercise, leading many experts to recommend physical activity as a way to ward off depression symptoms. A 2019 study recommended physical exercise when treating older individuals with depression.

Considering these factors, we should take the mBDNF finding as more than just a diagnostic tool, Charles Raison, MD, researcher and professor of human development and family studies at the University of Wisconsin-Madison, tells Verywell. “The first problem is this idea that major depression could ever have a biomarker,” Raison says. “There’d never be a biomarker that would identify every case of depression.”

The research is a collaboration between the University of Adelaide and Kunming Medical University and was published in theJournal of Psychiatric Researchthis month.

What This Means For YouResearchers are continuing to make innovations on how depression is diagnosed and treated. If you’re experiencing symptoms of depression, consider reaching out to your doctor or a mental health professional.

What This Means For You

Researchers are continuing to make innovations on how depression is diagnosed and treated. If you’re experiencing symptoms of depression, consider reaching out to your doctor or a mental health professional.

The Research

Researchers tested a new assay kit, an enzyme-linked immunosorbent assay (ELISA), in 215 people in China, 96 of which had not been diagnosed with clinical depression, 90 who had, 15 who had been diagnosed with bipolar disorder, and 14 who had a history of suicidal attempts.

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Confirming the link, researchers found that the more severe the depression, the lower the mBDNF level. Additionally, patients who had not been taking antidepressants had lower levels than those who had. Surprisingly, there was no difference in mBDNF between the 14 patients with a history of suicide attempts and the control group.

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The assay kit tested for mBDNF with 80-83% accuracy. It was important to develop their kit, researchers say, because the existing ones don’t distinguish between the three forms of BDNF, which have opposing functions. That is, the precursor and proBDNF “bind to different receptors, causing nerve degeneration and inflammation.”

More Emphasis on Therapies, Less on Diagnoses

While this research is important to a scientific understanding of how depression works, Raison says, it’s important that varied experiences of depression that don’t fall into this category aren’t invalidated.

“Let’s say that a person is desperately depressed, that they can’t get out of bed, that they’re planning on killing themselves,” Raison says. “They have really good levels of mBDNF. Would you tell them, ‘Sorry, it’s not possible. You can’t be depressed, you have good levels of mBDNF’? Or conversely, if somebody was perfectly happy, having a very good life, and they have low levels of mBDNF, would you tell them, ‘Well, look, you gotta get over this, you’re really depressed’?”

In addition to focusing too much on the diagnosis, Raison urges that research use biomarkers in the context of treatment.

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“If they showed that depressed people with low mBDNF had a very different response to treatment, then you’d want to measure it because it would tell you what to do right now in the world that we live in,” Raison says. “So, there is a need for these individualized predictive biomarkers, but the need is for things that will give us a treatment response, not a diagnosis.”

5 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Lin L, Fu X, Zhou X-F, Liu D, Bobrovskaya L, Zhou L.Analysis of blood mature BDNF and proBDNF in mood disorders with specific ELISA assays.Journal of Psychiatric Research. 2021;133:166-173. doi:10.1016/j.jpsychires.2020.12.021University of South Australia.Potential new biomarker for depression and bipolar disorder.Kurdi F, Flora R.Physical exercise increased brain-derived neurotrophic factor in elderly population with depression.Open Access Maced J Med Sci. 2019;7(13):2057-2061. doi:10.3889/oamjms.2019.574Lin L, Fu X, Zhou X, Liu D, Bobrovskaya L, Zhou L.Analysis of blood mature BDNF and proBDNF in mood disorders with specific ELISA assays.J Psychiatr Res. 2021;133:166-173. doi:10.1016/j.jpsychires.2020.12.021Medline Plus.BDNF gene.Additional ReadingBdnf gene: Medlineplus genetics.Potential new biomarker for depression and bipolar disorder. https://unisa.edu.au/Media-Centre/Releases/2021/potential-new-biomarker-for-depression-and-bipolar-disorder/Lin, L., Fu, X., Zhou, X.-F., Liu, D., Bobrovskaya, L., & Zhou, L. (2021). Analysis of blood mature BDNF and proBDNF in mood disorders with specific ELISA assays.Journal of Psychiatric Research,133, 166–173. https://doi.org/10.1016/j.jpsychires.2020.12.021

5 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Lin L, Fu X, Zhou X-F, Liu D, Bobrovskaya L, Zhou L.Analysis of blood mature BDNF and proBDNF in mood disorders with specific ELISA assays.Journal of Psychiatric Research. 2021;133:166-173. doi:10.1016/j.jpsychires.2020.12.021University of South Australia.Potential new biomarker for depression and bipolar disorder.Kurdi F, Flora R.Physical exercise increased brain-derived neurotrophic factor in elderly population with depression.Open Access Maced J Med Sci. 2019;7(13):2057-2061. doi:10.3889/oamjms.2019.574Lin L, Fu X, Zhou X, Liu D, Bobrovskaya L, Zhou L.Analysis of blood mature BDNF and proBDNF in mood disorders with specific ELISA assays.J Psychiatr Res. 2021;133:166-173. doi:10.1016/j.jpsychires.2020.12.021Medline Plus.BDNF gene.Additional ReadingBdnf gene: Medlineplus genetics.Potential new biomarker for depression and bipolar disorder. https://unisa.edu.au/Media-Centre/Releases/2021/potential-new-biomarker-for-depression-and-bipolar-disorder/Lin, L., Fu, X., Zhou, X.-F., Liu, D., Bobrovskaya, L., & Zhou, L. (2021). Analysis of blood mature BDNF and proBDNF in mood disorders with specific ELISA assays.Journal of Psychiatric Research,133, 166–173. https://doi.org/10.1016/j.jpsychires.2020.12.021

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Lin L, Fu X, Zhou X-F, Liu D, Bobrovskaya L, Zhou L.Analysis of blood mature BDNF and proBDNF in mood disorders with specific ELISA assays.Journal of Psychiatric Research. 2021;133:166-173. doi:10.1016/j.jpsychires.2020.12.021University of South Australia.Potential new biomarker for depression and bipolar disorder.Kurdi F, Flora R.Physical exercise increased brain-derived neurotrophic factor in elderly population with depression.Open Access Maced J Med Sci. 2019;7(13):2057-2061. doi:10.3889/oamjms.2019.574Lin L, Fu X, Zhou X, Liu D, Bobrovskaya L, Zhou L.Analysis of blood mature BDNF and proBDNF in mood disorders with specific ELISA assays.J Psychiatr Res. 2021;133:166-173. doi:10.1016/j.jpsychires.2020.12.021Medline Plus.BDNF gene.

Lin L, Fu X, Zhou X-F, Liu D, Bobrovskaya L, Zhou L.Analysis of blood mature BDNF and proBDNF in mood disorders with specific ELISA assays.Journal of Psychiatric Research. 2021;133:166-173. doi:10.1016/j.jpsychires.2020.12.021

University of South Australia.Potential new biomarker for depression and bipolar disorder.

Kurdi F, Flora R.Physical exercise increased brain-derived neurotrophic factor in elderly population with depression.Open Access Maced J Med Sci. 2019;7(13):2057-2061. doi:10.3889/oamjms.2019.574

Lin L, Fu X, Zhou X, Liu D, Bobrovskaya L, Zhou L.Analysis of blood mature BDNF and proBDNF in mood disorders with specific ELISA assays.J Psychiatr Res. 2021;133:166-173. doi:10.1016/j.jpsychires.2020.12.021

Medline Plus.BDNF gene.

Bdnf gene: Medlineplus genetics.Potential new biomarker for depression and bipolar disorder. https://unisa.edu.au/Media-Centre/Releases/2021/potential-new-biomarker-for-depression-and-bipolar-disorder/Lin, L., Fu, X., Zhou, X.-F., Liu, D., Bobrovskaya, L., & Zhou, L. (2021). Analysis of blood mature BDNF and proBDNF in mood disorders with specific ELISA assays.Journal of Psychiatric Research,133, 166–173. https://doi.org/10.1016/j.jpsychires.2020.12.021

Bdnf gene: Medlineplus genetics.

Potential new biomarker for depression and bipolar disorder. https://unisa.edu.au/Media-Centre/Releases/2021/potential-new-biomarker-for-depression-and-bipolar-disorder/

Lin, L., Fu, X., Zhou, X.-F., Liu, D., Bobrovskaya, L., & Zhou, L. (2021). Analysis of blood mature BDNF and proBDNF in mood disorders with specific ELISA assays.Journal of Psychiatric Research,133, 166–173. https://doi.org/10.1016/j.jpsychires.2020.12.021

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