America's addiction crisis is being ushered into a dangerous new era by rising levels of polysubstance abuse, as more people become addicted to deadly combinations of synthetic opioids and stimulants.

A massive survey recently released by a national drug-testing company strongly suggests we are well into the “fourth wave” of the opioid crisis. The three previous waves were driven by 1. prescription ...

Most research suggests that opioid overdoses involving multiple substances in the United States typically occur among people aged 25–54. However, a new study led by Boston University School of Public ...