People who continue to take antidepressants for a long period of time reduce their chances of relapse, a new study suggests.

The research, published in The New England Journal of Medicine today (29 September), found that patients who have been taking antidepressants for a long period of time are significantly less likely to experience a relapse into a depressive episode if they continue to take their medication than those who decide to stop.

The findings suggest long-term antidepressant use can be an effective method of reducing depression, it was concluded. The researchers hope this will help doctors and patients make more informed decisions on antidepressant prescribing and deprescribing.

It comes as the number of antidepressant items prescribed in England has increased over the past five years, with 20.5 million antidepressants prescribed between April to June of this year, a 7% increase from April to June last year.

Dr Gemma Lewis, lecturer at the division of psychiatry at UCL and lead author of the study, said: ‘Until now we didn’t know whether antidepressant treatment was still effective when someone has been taking them for many years.

‘We have found that remaining on antidepressants long-term does effectively reduce the risk of relapse. However, many people can stop their medication without relapsing, though at present we cannot identify who those people are.’

Of those who were involved in the study and discontinued the medication, over half (56%) experienced a relapse within a year, compared to 39% of those who stayed on medication.

The double-blind controlled study involved 478 primary care patients in England who had been taking antidepressants — including citalopram, sertraline, fluoxetine, or mirtazapine — for multiple years. Half the patients continued to take their medication and half discontinued for one year.

Dr Lewis also said: ‘Our findings add to evidence that for many patients, long-term treatment is appropriate, but we also found that many people were able to effectively stop taking their medication when it was tapered over two months.’

However, only half of the 56% of patients who experienced a relapse after discontinuation chose to return to antidepressant use.

The researchers said this could be because some of the relapses and withdrawal symptoms might not have been severe enough for the person to decide to return to their medication.

Professor Glyn Lewis, also from the division of psychiatry at and senior author of the study, said: ‘Antidepressants are effective but, like many medications, are not ideal for everyone. In our study, 39% of people who continued on the medication still experienced a relapse, although stopping antidepressants increased the risk of relapse further.

Other ways to prevent relapse include cognitive behavioural and mindfulness-based therapies, he explained.

Paul Lanham, a co-researcher, said: ‘Many patients taking antidepressants long-term have absolutely no idea what they would be like without antidepressants. Some will not want to find out, but others will.

‘These results show that staying on antidepressants does reduce the risk of relapse, but it does not guarantee well-being, and some people can stop antidepressants without a relapse.’

It follows a Cochrane review earlier this year, which found little evidence that current approaches for stopping long-term antidepressant use were safe and effective in people with recurrent depression.