New blood test could personalise depression treatmentBMJ 2016; 353 doi: https://doi.org/10.1136/bmj.i3203 (Published 08 June 2016) Cite this as: BMJ 2016;353:i3203
Scientists have developed a blood test to predict whether depressed patients will respond to common antidepressants. They said that this could herald a new area of personalised treatment for people with depression, where patients who have blood inflammation above a certain threshold could receive more aggressive treatment.
The research, published in the International Journal of Neuropsychopharmacology,1 focused on two biomarkers that measure blood inflammation: macrophage migration inhibitory factor and interleukin 1β. Previous research has shown that patients with depression who are resistant to conventional antidepressants have higher concentrations of inflammatory biomarkers in plasma or serum.
The researchers measured absolute mRNA values of these two markers in a sample of 74 patients with moderately severe depression who were taking part in a randomised drug trial comparing the tricyclic nortriptyline with the selective serotonin reuptake inhibitor escitalopram. They also measured the two markers in a second independent sample of 68 patients who were drug-free at baseline and then took a range of antidepressant drugs.
The study, which was funded by the UK Medical Research Council, found that patients whose levels of the two biomarkers were above a specified threshold level showed a 100% chance of not responding to conventional antidepressants. But those with inflammation below the same threshold were found to respond to first line antidepressants.
About half of all patients with depression do not respond to first line antidepressants, and a third are resistant to all available drug treatments. Until now it has not been established whether a patient will respond to common antidepressants, meaning that patients are treated with a trial and error approach, which can take months.
The two biomarkers examined in the study are involved in several brain mechanisms relevant to depression, including the birth of new brain cells, as well as the death of brain cells through oxidative stress.
The researchers said the findings meant that patients with blood inflammation above a certain level could be directed towards more assertive antidepressant strategies, which could include a combination of more than one drug. They are recruiting for a clinical trial to test whether adding an anti-inflammatory drug to an antidepressant improves depression.
Annamaria Cattaneo, study author at the Institute of Psychiatry, Psychology and Neuroscience at King’s College, London, said, “This is the first time a blood test has been used to precisely predict, in two independent clinical groups of depressed patients, the response to a range of commonly prescribed antidepressants. These results also confirm and extend the mounting evidence that high levels of inflammation induce a more severe form of depression, which is less likely to respond to common antidepressants.”
She added, “This study moves us a step closer to providing personalised antidepressant treatment at the earliest signs of depression.”