By Ines Aviles-Spadoni, M.S., M.A., UFTI Research Coordinator/Communications
Sherrilene Classen, professor and chair of the UF Department of Occupational Therapy, is an expert in the field of older driver behavior. Affiliated with the UFTI, she is currently involved in a new National Institutes of Health (NIH)-funded study along with Nicole Ennis, associate professor and vice chair of the Department of Behavioral Sciences at Florida State University.
The study seeks to investigate how the long-term, daily use of medical marijuana affects the way people drive in adults 50 and older, those who are suffering from chronic or severe pain. The team is also investigating the combined effects of medical marijuana and prescription opioid use on driving.
“We are so excited to launch this study as it will be the first to provide evidence-based data to examine the on-road performance, in real-time and traffic, of older adults who are using medical marijuana, with or without opioids,” Classen said.
Among those aged 50 and older, the use of medical marijuana has more than doubled in the past 10 years and is expected to grow each year by 2050. The reason? Chronic pain. What’s more, is that this population tends to have an elevated use of prescription opioid use for pain management. Combined, these two factors have led researchers to examine their effects on driving safety.
To gauge these effects, Classen and Ennis will be incorporating a driving task that will be conducted on an open road, under natural driving conditions. Additionally, the amount of marijuana used by study participants will be measured through electronic medical records, urinalysis, and data from RYAH Smart Inhaler devices. A comparison between a group of users and non-users of the marijuana/opioid combination will help to determine how these substances affect driving performance.
“THC (the active ingredient in marijuana) is associated with a 50% increased risk for crashes and driving,” Classen said. “While under the influence of marijuana, and when compared to driving unimpaired, the risk for a motor vehicle collision increases two times.
“Opioid use is associated with a 47% increased risk of crash initiation, while aging is associated with increased crash risk and declines in fitness-to-drive. As such, this study will have real-time on-road data collected from older adults who drive in traffic and who are meeting the conditions for medical marijuana and opioid use.”
In addition to studying the effects of these two substances on drivers 50 and older, the researchers will be looking at how these adults self-regulate their use. This is equally important because knowing how people manage the combined use of marijuana and opioids in their daily lives, especially during high-risk activities such as driving or operating heavy machinery, may inform safer practices for pain management.
With the use of medical marijuana expected to grow in the next couple of decades, this study has the potential to create policy recommendations derived from evidence-based interventions. It will also equip older adults with the knowledge and tools to utilize pain management along with safe driving practices.
“This study is critical to inform clinical decision-makers (e.g., physicians), policymakers, regulators, and those involved with legislation pertaining to driving safety among older adults who are also using opioids and/or medical marijuana,” Classen said. “As such, we are expecting that this study will make a significant contribution to public health—both for older drivers who are driving impaired and for other road users who may be in their vicinity.”