Antidepressants are no better at making people feel happier than taking no medication at all, a study claimed today.
Patients on the drugs did not have a significantly better quality of life compared to depressed people who were not on the pills, the analysis found.
Researchers looked 17.5million US adults with depression over 10 years, with around half on medication and half not.
Results showed a slight improvement in mental health in both groups, regardless of whether they were on antidepressants.
The researchers from King Saud University, Saudi Arabia, called for more long-term studies on patients on antidepressants to evaluate their impact on quality of life.
NHS doctors are already moving away from prescribing the drugs, which can cause a host of side effects.
The health service now advises that patients with mild depression be offered group therapy sessions before pills.
But independent experts said strong conclusions from the study cannot be drawn because those given the drugs were typically more depressed at the start, and therefore it was not a fair comparison.
They insisted other clinical studies have shown the drugs to improve overall quality of life.
Taking antidepressants does not make depressed people any happier than not taking the drugs, a study of 17.5million US adults found today
Around 7.3million adults — 17 per cent of the adult population — took antidepressants in England from 2017 to 2018, the latest date data is available for.
Some of the most commonly prescribed are citalopram, sertraline and fluoxetine under the brand names Celexa, Zoloft and Prozac.
Some 27.6million over-18s (13.2 per cent) were taking the drugs regularly in the US between 2015 and 2018, according to the Centers for Disease Control and Prevention (CDC) estimates.
The latest study, published in the journal PLOS ONE, used data from people who were surveyed and given health checks as part of another study.
How do antidepressants work?
It’s not known exactly how antidepressants work.
It’s thought they work by increasing levels of chemicals in the brain called neurotransmitters, which are linked to mood and emotion.
While antidepressants can treat the symptoms of depression, they do not always address its causes.
So they are usually used in combination with therapy to treat more severe depression or other mental health conditions.
Research suggests that antidepressants can be helpful for people with moderate or severe depression.
Studies have shown that they’re better than placebo for people with these conditions.
They’re not usually recommended for mild depression, unless other treatments like therapy have not helped.
The Royal College of Psychiatrists estimates that 50 to 65 per cent of people treated with an antidepressant for depression will see an improvement, compared to 25 to 30 per cent of those taking a placebo.
These included all adults in the country who were diagnosed with depression that were not institutionalised.
They had an average age of 48 and were mostly women (67.9 per cent).
More than half took antidepressants, while 43 per cent were not on the medication but still had a clinical diagnosis.
Researchers checked their Health-Related Quality of Life (HRQoL) scores when they were first identified by the database and two years afterwards.
The measure is used by the CDC as an indicator of quality of life, both mentally and physically, and is determined by patients answering survey questions about their wellbeing.
It is split into two areas: mental and physical health. Healthy people typically score around 90 on the scale.
Mental health scores increased in both groups over the two years, while physical scores declined.
For those taking the medication, mental health scores increased 2.9 per cent from an average of 40.32 to 41.50. Their physical health scores fell 1.5 per cent from 42.5 to 41.85.
Meanwhile, those not receiving antidepressants saw their mental health scores increase 2.2 per cent from 42.99 to 43.92. Their physical scores dropped from 43.86 to 43.31 (1.3 per cent).
Dr Omar Almohammed, a clinical pharmacist at the Saudi university, said there was no statistical difference between those taking the medication and those who didn’t.
This suggests using antidepressants does not significantly improve quality of life over time, they claimed.
But independent experts criticised the study for not taking into account the difference in depression levels between the two groups.
Dr Gemma Lewis, a psychiatrist at University College London, said: ‘In this study, the people who received antidepressants had worse quality of life, and are likely to have been more severely depressed, than those who did not.
‘This type of bias is difficult to eliminate in a naturalistic study like this, which does not involve an experimental design.
‘Clinical trials with experimental designs have found that antidepressants improve mental health related quality of life.’
Professor Eduard Vieta, a psychiatrist at the University of Barcelona, said: ‘The major limitation of this paper is that, as is often the case with these kinds of studies, the confounder by indication.
‘The inability to control for severity of depression between the two different groups is a crucial flaw and therefore there is little we can learn from this data.’