Depression and bipolar depression can now be detected using a blood test

A recent study done on the levels of nerve growth factor could help doctors detect depression and bipolar depression using a simple blood test. The researchers found out that the levels of nerve growth factor were lower in people with depression or bipolar disorder than in healthy controls.

This would help doctors potentially use levels of the growth factor to monitor the effects of antidepressant treatments on patients.

A protein found in human blood lowers as a result of depression

In adults, a protein called brain-derived neurotrophic factor (BDNF) promotes the growth and survival of nerve cells. It’s been found that psychological stress reduces blood levels of one form of the protein, called mature BDNF (mBDNF), and the low levels are associated with depression.

Recent studies in animals by Professor Xin-Fu Zhou of the University of South Australia in Adelaide and his colleagues found out that the injection of proBDNF into the brain or muscle can trigger depressive behaviors.

Working with the University of Adelaide and Kunming Medical University in Yunnan, China, they used the new test to show that people with depression or bipolar disorder have significantly lower levels of mBDNF in their blood than healthy controls.

How the blood test measures the amount of mBDNF protein in the blood

Prof. Zhou and his team developed a test to measure mBDNF levels in the blood more accurately.

The researchers applied their test to blood samples from 90 inpatients with major depressive disorder, 15 inpatients with bipolar disorder, and 96 healthy controls. They also tested samples from 14 other people with a history of suicide attempts in the past 10 years.

The test revealed that the participants with major depression or bipolar disorder had significantly lower levels of mBDNF in their blood compared with the test controls.

Those with severe symptoms of depression also had significantly lower levels than those with moderate symptoms. In addition, people who were taking antidepressants had higher levels than those who were not.