For years, marijuana has been labeled a so-called “gateway” drug, blamed for leading drug users down the path toward harder, more destructive drug use.

A review of studies in the journal Trends in Neuroscience, however, indicates that not only is cannabis unlikely to lead to harder drug use, it shows signs of being useful in the treatment of opioid addiction.

The review examined multiple studies and found that states that had legalized marijuana reported a reduction in opiod use. Further, these states also reported fewer prescriptions for opioid painkillers, a lower number of opioid overdoses than states without medical marijuana and reported fewer opioid-involved car fatalities.

According to the study, more than 90 Americans die every day from opioid overdoses and 80 percent of new heroin users say they started out mis-using opioids.

The review suggests that one particular component of marijuana – cannabidiol or CBD – shows promise for treating opioid addiction. Researchers say CBD has minimal side effects and no toxicity.

The lead author of the review says the potential addiction-curbing properties of cannabis need more study.