Nearly 20 percent of people in the study reported recent use of a prescription medication with the potential for impairment, but not all said they were aware that the medication could affect their driving, despite the potential for receiving warnings from their doctor, their pharmacist, or the medication label itself.
The percentages of those who said they had received a warning from one of those sources varied by type of medication: 86 percent for sedatives, 85 percent for narcotics, 58 percent for stimulants, and 63 percent for antidepressants.
In the report, researchers used data from the 2013-2014 National Roadside Survey, which asked drivers randomly selected at 60 sites across the United States questions about drug use, including prescription drugs. A total of 7,405 drivers completed the prescription drug portion of the survey.
Although it is unclear if the study participants actually received the warnings, or if they did receive the warnings but didn't retain the information, the authors say this scenario is in need of further research.
In this study, the type of medication in question was also related to drivers' perceptions about their impairment risk. They were most likely to think that sleep aids were the most likely to affect safe driving, followed by morphine/codeine, other amphetamines, and muscle relaxants. Attention-deficit hyperactivity disorder (ADHD) medications were viewed as least likely to affect driving risk. Sleep aids were also viewed as the most likely to cause an accident or result in criminal charges, and ADHD medications were viewed as the least likely.