Most common antidepressant barely relieves symptoms
THE most commonly prescribed antidepressant barely relieves symptoms of depression, a study has found.
The largest independent investigation ever undertaken found patients taking sertraline experienced negligible improvements in mood.
Published in The Lancet Psychiatry, it comes amid mounting controversy over increased use of antidepressants, with roughly 7.3 million people in England issued prescriptions every year. Last night the study’s authors said they were “shocked and surprised” by the results, and called for the development of new classes of medication.
But in the absence of better drugs, they did not call for current prescribing practice to be changed because the trial also showed sertraline was effective in reducing anxiety, which often accompanies depression.
The new trial is the largest held without the involvement of the pharmaceutical industry. It is also the most in-depth examination of sertraline, a type of selective serotonin reuptake inhibitor, in patients with a range of depression severities rather than just in severely depressed patients in specialist mental health units.
The study involved 654 people aged 18 to 74 who were given the antidepressant for 12 weeks or a placebo. The results showed depressive symptoms were 5 per cent lower after six weeks in the sertraline group, which was not “convincing evidence” of an effect.
After 12 weeks, there was a 13 per cent reduction, a finding experts described as “weak”. But the drug did offer clear benefits in reducing anxiety, with a 21 per cent reduction in symptoms at six weeks and 23 per cent at 12 weeks.
This is likely to explain why patients taking sertraline were twice as likely to say they felt generally better compared with the placebo group.
Symptoms of depression include poor concentration, low mood, trouble with sleep and lack of enjoyment, whereas anxiety is present as worry,
nervousness, irritability and restlessness. Prof Glyn Lewis, who led the research at University College London, said: “We were shocked and surprised when we did our analysis. There is no doubt 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.”
He suggested new, more effective classes of antidepressants could be based on ketamine, psilocybin (the psychedelic in magic mushrooms) and anti-inflammatories. It is thought that 4million people in England are longterm users of antidepressants. Prescribing data shows that SSRIS such as sertraline make up 54 per cent of antidepressant prescriptions.
Scientists responded to the study by pointing out some of the patients had very mild symptoms of depression, making it less likely that sertraline would cause an improvement. But others pointed out this was exactly the basis upon which doctors tended to hand out the drugs.
Dr Gemma Lewis, co-author of the research, said: “It’s really important to understand that anxiety symptoms are very common among people with depression. It appears that people taking the drug are feeling less anxious, so they feel better overall, even if their depressive symptoms were less affected.
“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.”
Prof Helen Stokes-lampard, of the Royal College of GPS, said: “It often takes a while for patients to feel the full benefits of modern antidepressants and they work best when taken for significant periods of time – one reason why doctors will often review patients after several weeks of use and then prescribe a fairly long course of the drugs, if they appear to be beneficial.”