A new paper out of Canada suggests that antidepressants are increasingly being used for conditions other than depression, with 45 percent of prescriptions in the study prescribed for conditions such as insomnia, anxiety and pain.

The study examined the prescription records of patients who visited select doctors in the province of Quebec between the years 2006 and 2015 and focused on those that were prescribed antidepressants.

The results revealed that out of 100,000 such prescriptions, just 55 percent were prescribed for the treatment of depression, while the remaining 45 percent were used to treat anxiety disorders, pain, insomnia and various other conditions. Furthermore, 30 percent of the prescriptions fit the criteria for off-label use, meaning the circumstances that they were prescribed under are not approved by regulatory agencies such as the Food and Drug Administration (FDA).

"I wasn't surprised by the indications themselves, but I was surprised by the extent," said Jenna Wong of McGill University and lead author of the study.

The data suggests that around six percent of all drugs prescribed were antidepressants. In terms of the rates of off-label antidepressant use, the numbers ranged from 47 percent for anxiety disorders to 97 percent for insomnia.

Off-label prescribing isn't illegal, and the FDA gives doctors the freedom to judge their patients' needs as they see fit. However, the problem with the practice is that there is no good evidence for the effectiveness of their use in many situations. This doesn't mean that anti-depressants are dangerous or ineffective in the treatment of insomnia, anxiety and pain, it just means that we don't know definitively whether they are or aren't.

Wong claims that she doesn't want to demonize off-label prescribing - she just wants to highlight how common the practice is.

"I think a lot of patients aren't aware that the antidepressants they're being prescribed for a particular problem sometimes have little sound scientific evidence behind them, and the same could be said for many doctors," she said.

Furthermore, pharmaceutical companies typically won't fund off-label research, and Wong hopes that her research will help push government policymakers to fund these studies due to the important implications that they have for the field.

The findings were published in the May 24 issue of The Journal of the American Medical Association.