20 September 2012

Why antidepressants work better for some

Scientists have identified biological markers in the blood which should help doctors match patients to the best type of treatment for depression.


British scientists have identified biological markers in the blood which should help doctors match patients to the best type of treatment for depression.

The aim is to end the "trial and error" prescription of antidepressants, which is often the only way depressed patients can find the most effective treatment, said researchers regarding what they described as a small but promising study.

"The study shows that we could use a blood-based "test" to personalise the treatment of depression," said Carmine Pariante of King's College London's Institute of Psychiatry, who led the study.

She and colleagues found that high levels of inflammation - which show up in biological markers in the blood - are part of the mechanism leading to depression, especially to particular forms of the condition that do not respond well to mild or low-dose antidepressants.

"If a patient had high levels of inflammation, they could immediately begin with a more intensive treatment programme, such as combining antidepressants or stepping up the doses," Pariante said.

Depression a growing problem

Major depression affects around 20% of people at some point in their lives. The World Health Organisation (WHO) predicts that by 2020, depression will rival heart disease as the health disorder with the highest global disease burden.

While there are many antidepressants on the market, including top seller Prozac, it is widely accepted that many antidepressants work in only half of patients half of the time, and drugmakers are struggling to come up with a new generation of drugs in this field.

In the study published in the journal Neuropsychopharmacology, Pariante's team set out to try to identify two types of biomarkers - ones which could predict future response to antidepressants, called predictors, and others which are targeted by antidepressants and change over the course of treatment, called targets.

The researchers explained that in human cells, information from genes is transcribed into so-called messenger RNA, or mRNA, before it becomes visible as a physical or biochemical sign. So the team monitored the patients' mRNA before and after they were treated with one of two antidepressants - escitalopram or nortriptyline.

What the study found

Escitalopram, sold under various brand names including Lexapro, Seroplex, Cipralex and made by generic drugmakers, is a serotonin reuptake inhibitor (SSRI).

Nortriptyline, sold under the brand names Sensoval, Aventyl and others, is an older type of antidepressant known as a tricyclic. They are both commonly prescribed as first line antidepressant treatments in Britain and other countries.

After eight weeks of treatment, the researchers found that patients who were not getting any better were ones who had significantly higher levels of three inflammation markers before treatment started.

This suggests these three signals could be used to find patients who are least likely to respond to antidepressants, allowing doctors to consider a more tailored or "personalised" approach to treatment from the start, the researchers said.

"This is a small study, but the findings are promising," they said in a statement.

"Personalised treatments for depression could help us avoid the current 'trial and error' way of prescribing antidepressant medication."

Do you suffer from depression? How do you cope? E-mail us at

(Reuters Health, September 2012)

Read more:

Caring for someone who is depressed


Read Health24’s Comments Policy

Comment on this story
Comments have been closed for this article.

Ask the Expert

Depression expert

Michael Simpson has been a senior psychiatric academic, researcher, and Professor in several countries, having worked at London University in the UK; McMaster University in Canada; Temple University in Philadelphia, USA.; and the University of Natal in South Africa.

Still have a question?

Get free advice from our panel of experts

The information provided does not constitute a diagnosis of your condition. You should consult a medical practitioner or other appropriate health care professional for a physical exmanication, diagnosis and formal advice. Health24 and the expert accept no responsibility or liability for any damage or personal harm you may suffer resulting from making use of this content.

* You must accept our condition

Forum Rules