Blood test may help GPs diagnose depression – and best treatment approach for patients

Blood test sample pot

Scientists at King’s College London believe they may have found a way to diagnose depression and identify the most appropriate treatment approach for patients - all via a simple blood test.

Publishing the findings in the International Journal of Neuropsychopharmacology, the researchers found that patients who tested positive for two specific biomarkers - macrophage inhibitory marker (MIF) and interleukin-1beta – were found to have depression that was more likely to respond to “more assertive” SSRI and tricyclic antidepressant medication.

The prescribing of antidepressants is, according to experts, often a process of trial and error, with numerous drugs trialled before a patient finds one that is effective and suited to them. While antidepressants are considered safe, some people may experience unwanted side effects, which may put patients who are already experiencing difficulties off the potentially lengthy process of finding the correct drug or combination of drugs that work for them.

Helping depressed people recover sooner

But lead researcher Professor Carmine Pariante, from the Institute of Psychiatry, Psychology & Neuroscience at King’s College says that, subject to further study and development, this breakthrough could be the key to providing a tailored-to-the-individual treatment plan from the outset, with the potential for helping depressed patients recover sooner. Professor Pariante says: “About a third of patients might have these inflammatory markers and they would be people we might encourage to go on more aggressive treatment.”

Blood test sample

Inflammation linked to effect of stress on the body

Raised inflammatory markers are suspected to be the result of stress on the body – which may also indicate the severity of the depressive episode. Adding to treatment complexity, this inflammation may prevent prescribed drugs from working efficiently, so the team are also looking into the possible benefits of taking anti-inflammatory medication alongside antidepressant treatment.

Professor Pariante explains: “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.”

However, he warns: “Patients should not change their medication on their own or take an anti-inflammatory without guidance from their doctor.”

New approach has “real game changer” potential

Brian Dow from the charity Rethink Mental Illness says of the development: "This new approach to antidepressants has the potential to be a real game changer, and these findings are a promising start.

"Anti-depressants can be a lifeline if you have a mental illness like depression, OCD (obsessive compulsive disorder) or anxiety, but it's not much of a lifeline if it takes years of trial and error to get to the right kind.

"In the meantime, changing from one kind of medication to the next can mean having to deal with different side effects every time, not to mention withdrawal symptoms from coming off one to go on another.

"We hope this new research creates a much needed short cut to a future where it's no longer luck of the draw when it comes to vital medication."

While medication is not the only treatment approach for depressive illness, many experts agree that a combination of treatment approaches is likely to yield the best results for patients.

Stephen Buckley, of UK mental health charity Mind says: "Different people will find that different treatments help to manage their mental health - what is most important is that people have the knowledge needed to access the treatment that works for them, whether this is medication, or alternatives such as talking therapies, or a mixture of both."

Woman sitting at windowsill

Recognising depression – when to seek help

According to the Royal College of Psychiatrists, signs that you may have developed depression include:

  • Persistent sadness or low mood
  • Feeling unable to enjoy things you used to
  • Losing interest in life
  • Difficulty making decisions
  • Feeling unable to cope with things that you used to find easy or straightforward
  • Feeling exhausted
  • Feeling restless or agitated
  • Loss of appetite or sometimes overeating
  • Difficulty sleeping
  • Loss of libido, or sex drive
  • Thoughts of harming yourself

If these symptoms sound familiar, make an appointment to see your GP or confide in someone you trust and tell them how you are feeling.

You may also find it useful to read our article, Men and Depression.


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About the author

Georgie Fenn, writes most of our news articles and social media posts.