According to the most extensive study of its kind, approximately one in six people who discontinue antidepressants will experience withdrawal symptoms directly caused by the medication, a figure lower than previously estimated.
A new analysis published in The Lancet Psychiatry of randomized controlled trials found that 15% of patients will experience one or more discontinuation symptoms that are directly caused by stopping the drugs, while around 2%-3% will suffer severe symptoms.
Previous research has suggested much higher rates of withdrawal symptoms, with 56% of all patients affected, though experts have said this figure is not robust.
Stopping antidepressants can lead to various symptoms or none at all. The most frequently reported are dizziness, headache, nausea, insomnia and irritability.
Discontinuation symptoms typically occur within a few days, and the new study found they lasted from 1-5 to 196 days.
Researchers in Germany looked at a range of antidepressants for the work, which included data from 21,000 patients involved in 79 pieces of research.
Most (72%) of those included were women and the average age was 45.
From a list of 11 separate antidepressants, citalopram, sertraline and fluoxetine – which are the most commonly used in the U.K. – they had the lowest chances of suffering withdrawal symptoms.
According to researchers, fluoxetine, for example, takes longer to leave the body and may account for fewer withdrawal effects.
However, venlafaxine was second highest for people experiencing symptoms.
In a linked editorial, professor Lewis and his colleague Dr. Gemma Lewis said many of the studies in the new overall analysis were small, "often using antidepressants not commonly used now, and studying people who had not taken the antidepressants for a very long time."
But they added: "Despite these limitations, the results here are a substantial improvement on anything that has been published before."
Dr. Jonathan Henssler, from Charite – Universitatsmedizin Berlin, an author of the study, said, "There is strong evidence that antidepressants can be effective for many people who are experiencing a depressive disorder, either alone or alongside other treatments such as psychotherapy.
"However, they do not work for everyone, and some patients may experience unpleasant side effects. In patients who have recovered with the help of antidepressants, the decision from doctors and patients may be to stop taking them in time," he said.
"Therefore, it’s important both doctors and patients have an accurate, evidence-based picture of what might happen when patients stop taking antidepressants. It’s important to note that antidepression discontinuation symptoms are not due to antidepressants being addictive. There is a crucial need for all patients stopping antidepressants to be counseled, monitored and supported by healthcare professionals. However, our findings, which consolidate data from a large number of studies, should also provide reassurance that rates of discontinuation symptoms are not as high as some previous single studies and reviews have suggested," he added.
The research found stopping taking imipramine, paroxetine and venlafaxine was associated with a higher risk of severe symptoms compared with other antidepressants.