The number of overdose deaths was up for the 11th year in a row with prescription drugs leading the way.

Opioid painkillers such as OxyContin and Vicodin are involved in many unintentional overdose deaths.

Researchers report drugs prescribed for mental health including benzo-diazepines, antidepressants, and anti-psychotics are often found in combination with opioids when patients overdose.