Do antidepressants work? Scientists are divided over the long-term benefits

The more prevalent antidepressants become, the more questions they raise. These drugs are one of the most prescribed types of medication in the United States, so much so that more than one in eight Americans over the age of 18 have already taken them, according to a survey by the CDC (Centers for Disease Control and Prevention). Despite this, very little is known about how well they work in the long term and, in particular, how they affect overall quality of life, experts say.

Most clinical trials of the drugs followed people who took antidepressants for just eight to 12 weeks. So it’s not clear what happens when patients take these drugs longer than that, said Gemma Lewis, a research psychologist at University College London who studies the causes, treatments and prevention of depression and anxiety.

“We need to follow people who are using and who aren’t using antidepressants longer to find out what the long-term ramifications are,” she explained.

A recent study published in the journal PLoS One, conducted to address these questions, compared changes in quality of life reported by Americans with depression who took antidepressants over two years to changes reported by people with the same diagnosis but who did not take the medicines.

The study included people who took all types of antidepressants, including selective serotonin reuptake inhibitors like Prozac, serotonin and norepinephrine reuptake inhibitors like Effexor, and older antidepressants like clomipramine and phenelzine.

The researchers assessed mental and physical quality of life, using a survey with questions about people’s physical health, their energy levels, moods, pain and ability to perform daily activities, among other issues.

The article found no major differences in the changes in quality of life reported by the two groups, a fact that suggests that antidepressant medications may not improve quality of life in the long term.

Both groups reported slight improvements in the mental aspects of quality of life over time and slight declines in their physical quality of life. But the study is flawed, researchers say, and certainly does not provide a definitive answer to the debate over the effectiveness of antidepressants.

One problem was that the study, based on data from more than 17 million Americans who participated in the US Medical Expenditure Committee Survey, compared people who may have had different levels of depression.

for Dr. F. Perry Wilson, a clinical public health researcher at the Yale School of Medicine and not involved in the study, it is likely that individuals who were prescribed antidepressants had more severe depression than those who were not prescribed.

Still, it’s difficult to draw conclusions based on the survey’s findings, he said, because “people with more severe depression may be less likely to improve their mental quality of life scores over time,” for reasons unrelated to the antidepressants they use. take.

Another issue is that people who were taking antidepressants could have been taking them for some time — so some of the quality-of-life improvements may have occurred before they were tracked by the study, Lewis said.

For her, this type of study “works best when it is possible to measure people’s quality of life before they start taking antidepressants”, when researchers can observe how people’s lives change immediately after starting to use the medication and also some time later. afternoon.

Omar Almohammed, a pharmacologist at King Saud University in Saudi Arabia and co-author of the study, countered that it is still reasonable to predict continued improvements in quality of life, even long after antidepressants have started.

“If we don’t see improvement with continued use of these drugs, the right decision may be to discontinue their continued use,” or add another type of treatment, such as cognitive behavioral therapy, which aims to change people’s thinking patterns, he said. .

But medications are often an easier and cheaper solution. People may have difficulty accessing therapy because of a lack of specialized professionals and because mental health treatments are often not fully covered by medical insurance.

Clinical trials suggest that while antidepressants provide benefits in the first few months, the benefits are modest and much less pronounced among people with mild depression compared with those with severe depression. Experts are divided on whether these small benefits make a noticeable difference to people’s moods or their overall functioning.

Some doctors, for example, argue that the improvements felt by people taking antidepressants are not much more than what they might feel if they took sugar pills.

“Antidepressants have marginal short-term effects compared with a placebo,” said research psychiatrist Mark Horowitz of University College London. That’s not to say that many people don’t feel better when they take the drugs — it’s just that much of the improvement may come from the placebo effect, not the drug itself.

If you are taking antidepressants, Horowitz’s suggestion is that you consult your doctor to see if you should continue taking them and, if so, to check that you are still taking the most appropriate dose. The American Psychiatric Association recommends that patients who have had just one episode of depression take antidepressants for four to nine months. But, Horowitz said, antidepressants should start slowly, ideally under medical supervision.

Many people can benefit profoundly from these drugs and can benefit from taking them for the long term. But we all deserve to know more about how well they work and the risks they can pose when taken for years or even decades.

Clearly, more careful research is needed to determine how best to help the more than 16 million Americans who suffer from depression today — and whose symptoms may have worsened during the pandemic.

Translation by Clara Allain