To figure all this out, researchers from the Centers for Disease Control and Prevention researchers combed through a national database containing causes of death drawn from death certificates.
Because a quarter of death certificates don't specify the drugs involved in overdoses, the researchers say the findings on particular types of drugs are undercounts.
While it's clear that opioids present the biggest hazard overall, drugs prescribed for mental health conditions are also involved in many deaths.
Sedatives known as benzodiazepines were implicated in nearly 6,500 deaths and antidepressants in almost 4,000 deaths.
These bars show deaths attributed solely to one type of drug as a percentage of all deaths involving those drugs. The totals include deaths from combinations of medicines. There were, for example, 16,651 opioid-related overdose deaths in 2010, and 4,903 of those deaths, or 29.4 percent, involved no other type of drugs.
Courtesy of JAMA