Update On Driving Behaviors And Outcomes For Adults With ADHD
Update On Driving Behaviors And Outcomes For Adults With ADHD
Sam Goldstein, Ph.D.
This is a SamGoldstein.com Monthly Article - December, 2004
Copyright ? 2004 Dr. Sam Goldstein - All Rights Reserved
One of the most frequently asked questions by parents of children with ADHD as their children transition into the middle adolescent years concerns driving. This month's article directly summarizes the known scientific literature on driving and ADHD. Rather than incorporate these data into one continuous article, I have decided to summarize each article in a narrative format. It is my hope that both professional and lay readers will not have a problem understanding my interpretation of this research. My review of these studies also appears in the December issue of ATTENTION! Magazine published by the CHADD organization.
Medical and mental health professionals routinely advise parents that learning to drive safely is a challenge for youth with ADHD. In response, some parents delay teaching their teens with ADHD to drive. Others limit the amount of driving they allow, while still others advised by doctors that when youth with ADHD take their medication they drive safely, often link driving privileges to "taking your medication." Surprisingly, there is a very small scientific literature concerning driving behaviors and associated risks in people with ADHD. The following are the articles that currently shape our knowledge of ADHD and driving.
Barkley, R., Murphy, DuPaul, G., & Bush, T. (2002). Driving in young adults with ADHD: Knowledge, performance, adverse outcomes and the role of executive functioning. Journal of the International Neuropsychological Society, 8, 665-672.
Driving behavior in adults with ADHD was evaluated by comparing 105, 17-28 year-old adults with ADHD to 64 community controls on five domains of driving ability and a battery of executive functioning tasks. The group with ADHD reported significantly more traffic citations and accidents. The group with ADHD was less attentive and made more errors during a visual reaction task under rule reversed conditions than the control group. They also obtained lower scores on a test of driving rules and decision making. Interestingly their basic driving behavior on a simulator was not different than the control group. Relationships between the cognitive and driving measures and the adverse outcomes reported were limited or absent. The authors suggest that this raises questions as to the use of these types of tests to screen for driving risks in adults with ADHD. Particularly in this study it is important to note that driving difficulties were not a function of comorbid disorders.
Cox, D.J., Humphrey, J.W., Merkel, R.L., Penberthy, J.K., & Kovatchev, B. (2004). Controlled-release methylphenidate improves attention during on-road driving by adolescents with ADHD. Journal of the American Board of Family Practice, 17, 235-239.
This ph armaceutical company funded study is the first to evaluate driving behavior in a car on an actual road segment. Twelve male adolescent drivers with ADHD were prescribed a standard dose of 1.0 mg/kg of controlled release methylphenidate in a repeated measures cross over study on two separate occasions (off/on medication randomized). Participants drove a standard sixteen mild road course incorporating rural, highway and urban streets. A rater blind to medication condition sat in the back seat and rated impulsive and inattentive driving errors. Impulsive driving errors were observed to occur rarely under both medication and no-medication conditions. Inattentive driving errors were more common and were significantly reduced while taking medication. The improvement in driving performance from first to second testing was positively correlated with medication dosage.
Cox, D.J., Merkel, L., Kovatchev, B., & Seward, R. (2000). Effect of stimulant medication on driving performance of young adults with ADHD: A preliminary double-blind placebo controlled trial. Journal of Nervous and Mental Disease, 188, 230-234.
These authors examined the performance of seven males with ADHD compared to six matched controls in a double-blind methylphenidate versus placebo cross over study. Using a driving simulator the authors found that compared with subjects without ADHD, those with ADHD had more career driving accidents and motor vehicle violations, drove worse on the simulator under placebo conditions, demonstrated significant improvement under the methylphenidate condition, rated themselves as driving poorer during the placebo condition and tended to perceive their driving to be better during the methylphenidate condition.
Cox, D.J., Merkel, R.L., Penberthy, J.K., Kovatche, V.B., & Hankin, C.S. (2004). Impact of methylphenidate delivery profiles on driving performance of adolescents with ADHD: A pilot study. Journal of the American Academy of Child and Adolescent Psychiatry, 43, 269-275.
This study also funded by a ph.armaceutical company compared the effect of driving behavior over time on six male adolescent drivers prescribed with either single dose methylphenidate delivered through a controlled-release oral system versus immediate release methylphenidate given in equal doses three times per day. Under each treatment condition, participations were maintained on medication for seven days then drove a sophisticated driving simulator at four afternoon times into the late evening. The primary outcome measure was each participant's computer-quantified impaired driving score. Participants demonstrated significantly less variability and better driving performance when receiving the single controlled-release oral system compared to standard release methylphenidate, particularly in the evenings.
Murphy, K. & Barkley, R.A. (1996). Attention deficit hyperactivity disorder in adults: Comorbidities and adaptive impairments. Comprehensive Psychiatry, 37, 393-401.
One hundred seventy-two adults with ADHD were compared to 30 adults referred to an ADHD clinic who were subsequently not given a diagnosis of ADHD. The ADHD group demonstrated a specifically greater prevalence of oppositional, conduct and substance abuse disorders and greater illegal substance use than did the non-ADHD group. Subjects with ADHD displayed greater self-reportive psychological maladjustment, more driving risks and more frequent changes in employment. Significantly more subjects with ADHD had experienced a suspension of their driver's license, had performed poorly, quit or been fired from their job and had a history of poor educational performance and more frequent school disciplinary actions against them. Multiple marriages were more likely in the ADHD group as well. Anxiety and mood disorders were not more prevalent in the ADHD group than in the non-ADHD group.
Nada-Raja, S., Langley, J.D., McGee, R., Williams, S.M., Begg, D.J. & Reeder, A.I. (1997). Inattentive and hyperactive behaviors and driving offenses in adolescence. Journal of the American Academy of Child and Adolescent Psychiatry, 36, 515-522.
Symptoms of ADHD and conduct disorder were strongly associated with driving offenses. Female symptoms of ADHD were significantly associated with driving offenses in a sample of over 900 adolescents followed longitudinally. Female symptoms of ADHD were significantly associated with driving offenses and more traffic accidents compared with other disorders or no disorder. It appears that at risk driving behavior cannot be entirely attributed to symptoms of ADHD as symptoms of Conduct or Oppositional Disorder were more frequently associated with driving offenses. This study adds to an increasing body of data suggesting that it is the development of moderate to severe disruptive disorders possibly in combination with ADHD that best predicts a host of environmental consequences (e.g., automobile accidents, substance abuse, trips to the emergency room, etc.).
Woodward, L.J., Fergusson, D.M., & Horwood, J. (2000). Driving outcomes of young people with attentional difficulties in adolescents. Journal of the American Academy of Child and Adolescent Psychiatry, 39, 627-634.
The association between problems with attention at age 13 and adverse driving outcomes measured at 21 years of age was examined as part of a 21-year longitudinal study of 1,200 New Zealand children. Young adults with high levels of attentional difficulty were at greater risk of motor vehicle accident, drinking and driving, and traffic violations. These associations were largely explained by the personal characteristics (gender, conduct problems) and driving experiences (length of time they held a license, distance drive) of young people with attentional problems. Even after the adjustment for the effects of confounding factors, however, adolescent attentional problems placed young adults at an increased risk of an injury, accident, driving without a license, and other traffic violations.
These studies, though limited in number, were well conducted and reflect an emerging trend. First, there is a consensus that people with ADHD experience more career driving accidents, motor vehicle violations and adverse driving behavior as measured on driving simulators. Second, the treatment of ADHD with stimulant medication improves driving simulator behavior. One small study has now demonstrated that the use of medication reduces the incidence of inattentive but possibly not impulsive adverse driving outcomes on the road. Third, people with ADHD recognize their driving problems; and fourth, a host of other variables, including psychiatric problems such as Conduct or Oppositional Defiant Disorders are also associated with increased driving problems. However, even after the adjustment for the effects of other contributing factors, adolescents and young adults with ADHD are at increased risk of injury, accidents and other traffic violations. Future research may better identify the combination of variables that predict both risk and improved driving behavior for people with ADHD.
