Antidepressants are generally safe, according to a new study by an international team of researchers. By assessing evidence from 45 meta-analyses, which combined the results from many studies, the researchers did not find strong evidence of adverse health outcomes associated with antidepressant use. The findings have been published in JAMA Psychiatry.

There has been a sharp growth of antidepressant use worldwide. These drugs rank third among prescribed medications and fourth among sold medications. It is estimated that up to 10% of American adults take at least one antidepressant. However, the safety profile of antidepressants has remained somewhat controversial. Meta-analyses combine the results from many studies, and some have found strong associations between antidepressants and some adverse health outcomes, while others have not.

"As far as we know, this is the first study to assess the safety and adverse health outcomes associated with antidepressant use on such a large scale considering real-world data. However, it is important to note that our study did not evaluate the efficacy of the drugs", says the study's lead author, Dr. Elena Dragioti, adjunct senior lecturer in the Department of Medicine and Health Sciences at Linköping University, Sweden.

Researchers systematically assessed the evidence from 45 reviewed meta-analyses that included more than 1,000 observational studies. These are studies that observe whether there are differences between individuals who are exposed to a treatment and those who are not, without any intervention from a researcher. The studies included covered different age groups, underlying psychiatric conditions, and possible adverse health outcomes.

"We found that all of the adverse health outcomes reported in observational studies that were supported by strong evidence were actually probably due to the underlying psychiatric conditions for which antidepressants had been prescribed, rather than the antidepressants themselves. Most of these studies also suffered from several biases, such as a lack of randomization," says Dr Marco Solmi, psychiatrist from the University of Padova, Neurosciences Department, and visiting researcher at the Institute of Psychiatry, Psychology & Neuroscience at King's College London, Psychosis Department, EPIC lab, who co-led the study.

"Even though we have shown that antidepressants are generally safe, we should note that adverse effects must be monitored clinically during antidepressant treatment. Further, we have only limited evidence from randomised clinical trials about long-term adverse health outcomes. Moreover, we were not able to assess several newer antidepressants due to limited available data", says senior author Dr. Evangelos Evangelou, epidemiologist from the University of Ioannina, Greece and Imperial College, London, UK.