Blood test can predict best depression treatment

7^th June 2016 - Scientists at King’s College London have developed a blood test to predict whether people with depression will respond well to certain types of antidepressants.

Currently doctors will try different medications until they find one that works.

Ending trial-and-error antidepressant prescribing

Finding the right antidepressant medication can be a hit and miss affair and difficult to get right first time when it comes to prescribing for depression. Until now there's been no accurate way of knowing which patients would respond well to which treatment.

Around half of all people with depression don't respond to first-line antidepressants and around a third are resistant to all available drug treatments. Some people may need higher doses of medication or a combination of treatments.

Each medication is usually tried for as long as 12 weeks, and if there is no response, another is tried, and again it may be weeks before it is evident the next treatment is not working either. This process can lead to a lengthy delay in finding the best treatment for an individual.

New blood test

The new research involved 142 volunteers in two groups with diagnosed depression and is published in The International Journal of Neuropsychopharmacology.

It involves testing for two things in the blood - macrophage migration inhibitory factor (MIF) and interleukin (IL)-1 beta. These are called 'biomarkers' and measure inflammation and oxidative stress in the brain. These factors have been linked with a poor response to antidepressants.

In the Kings College London study, samples were taken before and after people took different antidepressants.

Depending on the results, people were given the most appropriate dose of an antidepressant or were given combination treatment.

The researchers set a threshold in the test results to determine who'd get which treatment approach.

They found the blood test reliably predicted people's response to treatments, and therefore which treatments would be unlikely to work.

Quality of life

The authors of the paper have issued statements about their work. Professor Carmine Pariante says: "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.

"This study provides a clinically-suitable approach for personalising 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."

Dr Annamaria Cattaneo adds: "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."

More work would be needed before the test is used in the NHS, but the research team believes it brings ‘personalised psychiatry’ a step closer.

Dr Cattaneo says: "This study moves us a step closer to providing personalised antidepressant treatment at the earliest signs of depression."

This association of inflammatory markers with depression has led to the researchers developing a clinical trial to test whether adding an anti-inflammatory drug to an antidepressant improves treatment responses.

Although this is encouraging news, experts point out that medication is not the only answer when it comes to managing depression.

The research was funded by the Medical Research Council and the NIHR Maudsley Biomedical Research Centre.