Common antidepressant ‘works for anxiety, but not depression’

A common antidepressant does little to relieve symptoms of depression but is effective at cutting anxiety, researchers say.

Rise in numbers being prescribed antidepressants

The biggest study of its kind found that most people taking sertraline saw little or no effect on depressive symptoms, such as low mood, lack of interest and poor sleep, in the first six to 12 weeks of taking the drug.

However, sertraline did cut symptoms of anxiety, such as worrying and feeling nervous or restless, and people were twice as likely to say their overall mental health had improved and they felt better.

Experts said they were “surprised” by the findings relating to depression but it was clear the drugs helped cut anxiety and should continue to be prescribed.

The study, published in the journal the Lancet Psychiatry and led by University College London (UCL) researchers, was conducted in GP surgeries across England.

It included 653 people aged between 18 and 74 who experience depressive symptoms. The study split them into two groups.

The first group was given a dummy drug for 12 weeks while the second group was given sertraline.

The results showed depressive symptoms were 5 per cent lower after six weeks in the sertraline group, which was “no convincing evidence” of an effect.

After 12 weeks, there was a 13 per cent reduction – a finding the experts described as “weak”.

But the drug did offer clear benefits on reducing anxiety, with a 21 per cent reduction in symptoms at six weeks and 23 per cent at 12 weeks.

People on sertraline were twice as likely to say they felt better and their overall mental health had improved.

Professor Glyn Lewis, head of division at UCL Psychiatry, who led the study, said: “Antidepressants work but perhaps in a different way to the way we had originally thought.

“They seem to be working on anxiety symptoms first before any smaller, and later, possible effects on depression.

“We definitely need better treatments for depression – we need more research in this area.

“This is an unexpected result. Our primary hypothesis was that it would affect those depressive symptoms at six weeks and we didn’t find that. So it is an unexpected finding.”

The researchers said people with depression most often have symptoms of anxiety – something for which the drug seemed to offer clear benefits.

Dr Gemma Lewis, from UCL, said: “We hope that we have cast new light on how antidepressants work, as they may be primarily affecting anxiety symptoms such as nervousness, worry and tension, and taking longer to affect depressive symptoms.”

The study, funded by the National Institute for Health Research (NIHR), is the largest placebo-controlled trial of an antidepressant which has not been funded by the pharmaceutical industry.