LONDON, June 10 (UPI) -- Patients with depression often cycle through several antidepressant drugs before finding one that works, but a recent study suggests a blood test could help doctors more quickly determine the right one for each patient.
Measuring two biomarkers in blood correctly indicated the drug most likely to treat depression based on levels of inflammation in the body, which makes the condition worse and more difficult to treat, according to researchers at King's College London.
When doctors are selecting the right course of treatment for depression, they often cycle through a trial-and-error approach until finding the most effective one.
Each drug requires 12 or more weeks of use to get an accurate look at its effects, sometimes significantly prolonging the time before a patient improves, if they don't get worse during the process.
Previous research has linked elevated levels of inflammation to a lackluster response to drug treatment, often requiring stronger, less commonly used drugs in their treatment.
This lead researchers to test whether two indicators of inflammation -- macrophage migration inhibitory factor and interleukin-1β -- could tip them off to whether patients would respond to standard treatments, or be better off if given an alternative.
"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," Dr. Annamaria Cattneo, a researcher at King's College London, said in a press release. "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."
For the study, published in the International Journal of Neuropsychopharmacology, the researchers recruited two separate groups of patients, testing both before for the two biomarkers before selecting the drug to treat them with.
The first group of 74 patients was treated with either escitalopram or nortryptiline, and the second group of 68 patients was treated with a selective serotonin reuptake inhibitor, a serotonin and noradrenaline reuptake inhibitor or a tricyclic drug.
The researchers report in the study that 100 percent of patients with higher levels of the two biomarkers would not respond to more common drugs, while those below it responded to the most commonly prescribed medications.
"The identification of biomarkers that predict treatment response is crucial in reducing the social and economic burden of depression, and improving quality of life of patients," said Carmine Pariante, a professor at the Institute of Psychiatry, Psychology and Neuroscience at King's College London. "This study provides a clinically-suitable approach for personalizing antidepressant therapy -- patients who have blood inflammation above a certain threshold could be directed toward earlier access to more assertive antidepressant strategies, including the addition of other antidepressants or anti-inflammatory drugs."