Long-term antidepressant use associated with higher risk of withdrawal symptoms

Long-term antidepressant use associated with higher risk of withdrawal symptoms

People who have been taking antidepressants for more than two years are significantly more likely to experience withdrawal symptoms when stopping the drug compared to short-term users, finds a new study led by UCL researchers.

Long-term users also tend to have worse withdrawal symptoms and for a longer period of time than short-term users and are less likely to be able to stop taking the drug if they try to do so, according to published resultsPsychiatry research.

The study's lead author, Dr. Mark Horowitz, visiting clinical researcher from UCL's Department of Psychiatry, said: “Our results confirm what many researchers have long suspected, that the likelihood of experiencing withdrawal symptoms when stopping antidepressants is largely determined by duration of use.

"While coping with antidepressants may be easier for people who have only taken them for a short time, these drugs are commonly used for a long time. Half of people in the UK taking antidepressants have been taking the drug for over two years."

The study was based on survey responses from 310 participants in England who had accessed NHS primary care therapy services and had at one point tried to stop taking their prescribed antidepressant. Most participants - 62% - said antidepressants had been helpful for them.

Respondents were asked about an extensive list of potential withdrawal symptoms and self-reported whether the symptoms were mild, moderate, or severe. Across the group, 79% reported experiencing at least one withdrawal symptom and 45% reported experiencing symptoms that they classified as moderate or severe (30% and 15%, respectively).

Across the group, 38% said they couldn't stop taking antidepressants when they tried, rising to 79% among people who had been taking antidepressants for two years.

Because some withdrawal symptoms (such as anxiety, worsening mood, restlessness and fatigue) overlap with depression and anxiety symptoms and can represent a relapse, the researchers also found that 76% of respondents experienced at least one non-emotional withdrawal symptom such as dizziness, headache, vertigo or nausea, while 43% experienced four or none.

In the analysis by researchers in UCL's Department of Psychology and Linguistics, the team found that how long someone had been on an antidepressant was the main factor determining the incidence, severity and duration of withdrawal effects and whether someone was able to stop taking the medication. The differences between short-term and long-term users were not explained by the severity of the underlying depression or anxiety disorder.

The researchers found that those who had been on antidepressants for more than two years were 10 times more likely to experience withdrawal effects than those who had been taking them for less than six months.

Among people who had been taking antidepressants for two years, 64% reported moderate or severe withdrawal effects (25% reported severe effects), while among those who had been taking the drug for six months or less, the majority (73%) reported either no withdrawal effects or only mild symptoms, with only 7% experiencing severe withdrawal symptoms.

For long-term users, 30% reported withdrawal symptoms lasting more than three months. 12% experienced such symptoms for more than a year, while only 10.5% of short-term users experienced withdrawal symptoms for more than three months. For most short-term users, withdrawal symptoms resolved in less than four weeks.

This is one reason not to use antidepressants for longer than necessary - because this can make it harder to stop using them later. “

Dr. Mark Horowitz, visiting scientist at UCL's Department of Psychiatry

The researchers say one limitation of the study is that the survey response rate was less than one in five (18%). Respondents may have been more motivated to complete the survey if they were experiencing withdrawal symptoms, although the survey did not focus solely on withdrawal.

While researchers asked whether people tapered off antidepressants slowly using a tapering technique or quit all at once, the results were inconclusive because not enough participants tapered for more than four weeks. The researchers say that as other studies have suggested that tapering is beneficial, more research is needed into how best to taper off antidepressants and how they may blunt withdrawal symptoms.

Senior author Professor Joanna Moncrieff (UCL Department of Psychiatry) said: "Withdrawal symptoms are commonly experienced by people coming from antidepressants. Therefore we would recommend that people who wish to stop taking the medication should do so in consultation with an informed medical professional."

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