Experts said, if successful, the test could be a key moment in the quest for the holy grail of biological psychiatry. Photograph: Anthony Devlin/PA
Patients will potentially be able to avoid medications that do not help them and the test could start a ‘new era’ for personalised treatment of depression
Scientists have developed a blood test that could identify which people with depression will respond to treatment so that patients can avoid spending months taking antidepressants that do not help them.
The experts involved believe the breakthrough could lead to depressed patients receiving personalised treatments that are more likely to relieve their symptoms.
The Royal College of Psychiatrists said that, if it worked, the test could prove to be a key moment in the quest for the holy grail of biological psychiatry.
The scientists at King’s College London behind the development claim that their test “accurately and reliably predicts whether depressed patients will respond to common antidepressants, which could herald a new era of personalised treatment for people with depression”.
If the test proves effective it is hoped that by measuring patients’ level of blood inflammation it would identify which of them would benefit from receiving antidepressants soon after their diagnosis to stop their condition worsening.
About half of all patients with depression get no benefit from antidepressants the first time they take them and they never work for one in three people.
Currently it is impossible to establish who should or should not be given antidepressants, or combinations of them. That means that patients are tried on a succession of different drugs for 12 weeks or more and experience prolonged periods of ineffective treatment because their medication does not benefit them.
One in six Britons will suffer depression at some point in their life. Last year 61.5m prescriptions for antidepressants were issued in England.
Researchers focused on two independent clinical groups of depressed patients on two biological markers that measure inflammation of the blood, as heightened levels are associated with poor response to antidepressants. They found that blood test results above certain levels reliably predicted how well patients would respond to commonly prescribed antidepressants. Their findings have been reported in the International Journal of Neuropsychopharmacology.
“The identification of biomarkers that predict treatment response is crucial in reducing the social and economic burden of depression and improving quality of life for patients,” said Prof Carmine Pariante from KCL’s institute of psychiatry, psychology and neuroscience.
“This study provides a clinically suitable approach for personalising antidepressants therapy. Patients who have blood inflammation above a certain threshold could be directed towards earlier access to more assertive antidepressant strategies, including the addition of other antidepressants or anti-inflammatory drugs,” Pariante added.
Dr Cosmo Hallstrom, a spokesman for the Royal College of Psychiatrists, said: “Finding biological markers for depression (and other mental illnesses) has been the holy grail of biological psychiatry.
“Such a finding and a test to back it up would be critical to advancing our understanding of the biological causes of depression. It would accelerate our therapeutic interventions and make them more tailored to the needs of the patient.”
But further clinical research is needed to see if the findings can be applied in a clinical setting, Hallstrom added.
Stephen Buckley, head of information at the mental health charity Mind, said: “We welcome research which adds to our understanding of treatments and medications that may work for people experiencing mental health problems. These initial findings are interesting, but, as with all areas of mental health, there is still more research to be done.”
Mental health problems, including depression, are estimated to cost £105bn a year in England. The World Health Organisation has predicted that by 2020 depression will be the second biggest cause of health problems in the world.
This story describes a British study published in the International Journal of Neuropsychopharmacology that identified two biomarkers of blood inflammation that predict the probability of a patient responding to common antidepressants.
The King’s College London researchers suggest the findings may lead to a blood test to identify patients who could benefit from more aggressive treatment including combinations of antidepressants as well as antidepressants in tandem with anti-inflammatory drugs. The story states that scientists “have developed a blood test that could identify which people with depression will respond to treatment so that patients can avoid spending months taking antidepressants that do not help them.”
While the possibility of targeted therapy is exciting, and these results look promising, the story downplays the need for more research before such a blood test could be used for patient care. Nevertheless, it puts forth sensational terms such as “breakthrough” and “holy grail” to describe the findings.
Antidepressants are among the most commonly prescribed drugs, but often they don’t work. Approximately half of all depressed patients do not respond to first-line antidepressants and a third of patients are resistant to all available pharmacological treatments, according to research cited in the King’s College London study.
Clinicians often have difficulty determining whether a patient will respond to standard antidepressants or require a combination of drugs. In addition, antidepressants are often prescribed for patients who are not clinically depressed or do not stick with a medication long enough due to side effects. These factors have led to a spate of recent articles questioning the efficacy of antidepressants in general.
Tests to predict a patient’s likely response would target antidepressants to patients who stand to benefit, potentially helping patients find effective treatment sooner and reducing medical costs. It also would allow those identified as likely “non-responders” to conventional treatment to be treated more aggressively, for example with other medicines, transcranial magnetic stimulation or electro-convulsive therapy.
Costs were not included. If it’s not too soon to speculate that “this breakthrough could lead to depressed patients receiving personalized treatments that are more likely to relieve their symptoms,” then it’s not too soon to think about what that test might cost.
The story talks about “breakthroughs” and “holy grails,” but doesn’t provide any numbers to that effect. The accuracy figures are included in the study’s abstract and the story should have discussed them along with an explanation of what they mean.
The story mentions no potential harms. However, as with all screening tests, false-positive and false-negative results can be harmful in a number of ways.
The story does not explain how the study was performed nor describe its limitations. The study itself, though, points to several limitations, including a small sample size, the fact that the proteins used as biomarkers did not predict responses to specific drugs but rather to antidepressants in general, and that the findings may not be relevant to patients with chronic depression or those who have been resistant to multiple antidepressants — the very patients that might benefit most from a personalized approach. The results of this small, backward-looking study are susceptible to bias. Only a much larger, prospective clinical trial will show the value of this test in a more realistic clinical situation.
We were pleased to see this cautionary note: “But further clinical research is needed to see if the findings can be applied in a clinical setting, Hallstrom added.” However, this isn’t enough to enlighten readers.
There’s no sign of disease mongering.
The story includes two independent sources, but does not mention study funding or conflicts of interest. The research was funded by the government-run Medical Research Council and the National Institute for Health Research Maudsley Biomedical Research Centre, according to the King’s College London news release.
One researcher, Carmine Pariante, M.D., received funding directly or indirectly from pharmaceutical firms Johnson & Johnson, Lundbeck, GSK, and Pfizer as well as the UK-based Wellcome Trust, according to the study.
J&J has a vested interest in developing drugs that might be used after this blood test is given, so this was important to disclose.
Given the main focus of the story is blood tests, the apparent alternative would be no blood tests.
The story acknowledges in the third-to-last paragraph that “further clinical research is needed to see if the findings can be applied in a clinical setting.” That’s good–but we would have liked to seen this detail much higher. Also, we would have liked to seen some discussion of how many more steps are in the process to develop an effective blood test for clinical use.
A blood test to predict patient response to antidepressants would likely have value, but not necessarily as a “holy grail” as mentioned in the story. There is other active research in this area, and as we’ve discussed before, there are lots of important caveats to keep in mind.
The story draws heavily on a news release from King’s College London without attribution. However, it barely satisfies our criteria by offering comments from two outside sources, the Royal College of Psychiatrists and mental health charity Mind.