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Blood test may predict effectiveness of depression treatment
Last reviewed: 01.07.2025
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Scientists at Loyola University say they have found the first reliable way to predict whether an antidepressant will work for a particular person with depression.
The method turned out to be a blood test for a protein called vascular endothelial growth factor (VEGF). Loyola scientists found that depressed patients who had high levels of VEGF in their blood experienced 85 percent or complete relief from their depression after taking escitalopram (brand name Lexapro®), compared with 10 percent of depressed patients who had low levels of VEGF.
About 60% of patients with depression do not fully respond to the medications prescribed by their doctor. Therefore, doctors often prescribe different drugs over and over again before they find one that really works. "If we could predict the effectiveness of antidepressants in advance, it would simplify the doctor's job and the patient's treatment," said study author Haleris.
The study involved 35 patients who were taking escitalopram to treat major depressive disorder. Escitalopram belongs to a class of antidepressants called selective serotonin reuptake inhibitors (SSRIs). Other common SSRIs include Prozac, Paxil, and Zoloft.
One possible hypothesis explaining the mechanism of action of SSRIs is the neurogenic theory, according to which SSRIs restore nerve cells in certain parts of the brain that atrophy in patients suffering from depression.
A study conducted by Loyola scientists confirmed this theory. The use of escitalopram led to the regeneration of inactive neurons in the corresponding areas of the brain. This regeneration occurred through VEGF. In the brain, VEGF stimulates the growth of blood vessels and activates brain cells. It seems that patients with higher levels of VEGF experienced more intensive regeneration of neurons, which was accompanied by a reduction in symptoms of depression.
If the findings of the study are confirmed by further research, it could greatly help doctors in determining the treatment strategy for depression. For example, if a patient has low levels of VEGF, a doctor might not prescribe an SSRI and try alternative classes of antidepressants, such as bupropion, or other treatments for depressive disorders, including psychotherapy or transcranial magnetic stimulation.
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