Driving performance of 35 adolescent ADHD patients (19 boys/16 girls; mean age 17.8 years) on a driving simulator was compared while taking OROS methylphenidate (Concerta, 72 mg), mixed dl-amphetamine salts (Adderall XR, 30 mg), or placebo in a randomized, double-blind, crossover study at University of Virginia, Charlottesville. Both treatments led to better overall driving performance. A comparison of treatments showed that Concerta was associated with significantly better driving peformance than placebo or Adderall XR, and resulted in better steering (less driving across midline and off road), better speed control (less speeding and less erratic speeds), and less impulsive driving (less inappropriate breaking and indecision at intersections and left turns). Comparing driving performance tested at 5, 8, and 11 PM, the worst performance occurred at 8.00 PM, and the best performance for both Concerta and Adderall XR was at 11.00 PM, 15 hours after taking the medication. Participants’ subjective ratings were not significantly different from the simulator scores. They were aware of improved driving on Concerta compared with placebo, but not aware of improved performance on Adderall XR compared to placebo. Improvements in driving performance on the laboratory simulator corresponded with fewer lifetime collisions. 
COMMENT. Long acting stimulant medication in adolescent ADHD patients who drive results in improved performance and fewer collisions. Both stimulant preparations, OROS MPH (Concerta) and dl-amphetamine (Adderall)-XR, are effective. The greater improved performance with MPH versus amphetamine in this study is probably a reflection of the choice of dosage, which seems to favor Concerta. If further studies are planned, a dose optimization design should be included. It is also surprising that the best driving performance with medication in this study is at 15 hours after taking a dose, when lower blood levels of drug would be expected. The use of stimulants in adolescents with ADHD should not be limited to daytime and school hours, if patients are regular drivers. These findings confirm several previous reports showing a correlation between ADHD in adolescents and an increased rate of motor vehicle collisions, especially in untreated patients (Ped Neur Briefs Aug 1993) [2, 3, 4]. ADHD young adults are twice as likely to be cited for unlawful speeding, have more crashes, and more accidents involving bodily injury, when compared to non-ADHD adult control subjects.