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ADDERALL XR significantly improves driving performance, attention in young adults with ADHD

November 09, 2005

ADDERALL XR® (mixed salts of a single-entity amphetamine product) significantly improved driving performance, cognitive function and attention in young adults with attention-deficit/hyperactivity disorder (ADHD) in a controlled driving simulator study conducted by the Washington Neuropsychological Institute and presented today at the 18th Annual U.S. Psychiatric & Mental Health Congress in Las Vegas, NV. "Adolescent and adult patients often fail to appreciate the effect that ADHD symptoms such as inattention have on daily activities such as driving," said Gary Kay, Ph.D., president of the Washington Neuropsychological Institute. "Our study demonstrates that ADDERALL XR helps young adults improve their ability to drive and do so safely over a 12-hour period."

Accidents are the leading cause of death until age 40. A study by Barkley et al published in 2002 demonstrated that adults with ADHD had a significant higher incidence of traffic violations, and license suspensions than patients without ADHD. This research suggested that ADHD patients were five times more likely than non-ADHD patients to have five or more speeding tickets and three times more likely to have had three or more vehicular crashes. Because of this data, Kay felt it was important to study the effect that ADDERALL XR, a major ADHD therapy, has on driving performance in young adult patients with ADHD.

Patients with ADHD taking ADDERALL XR demonstrated significant improvement in driving safety and performance, as measured by a 2.5 point reduction in their average Driving Safety Score (DSS), compared to 2.5 point gain among those on placebo (P<.005). The investigators determined the participants' DSS from mean scores derived from safety-related driving parameters, including speeding tickets, traffic tickets, crashes, crash avoidance rating, time to collision and excess speed, as presented on the STISIM DriveTM Simulation System at both testing visits, weeks three and six.

Furthermore, ADDERALL XR significantly improved ADHD symptom control in young adults with ADHD as compared to those on placebo. Eighty percent of patients experienced at least a 30 percent reduction in their ADHD symptoms based on the ADHD Rating Scale (ADHD-RS) score when taking ADDERALL XR.

ADDERALL XR also had significant effects on the participants' attention, an important cognitive ability, as measured on the validated Kay Continuous Performance Test (KCPT), a 12-minute visual vigilance test that measures the ability to maintain attention during a monotonous, repetitive task.

For example, participants treated with ADDERALL XR had significantly improved reaction time and significantly fewer lapses in attention compared to those receiving placebo. There was a particular advantage for those patients who received ADDERALL XR at the first test visit. Their performance was normal on this test of vigilance. In contrast, those who had received placebo at the first visit performed in the deficient range. At the second test visit, those individuals who had been taking ADDERALL XR at the time of the first visit were now taking placebo. Their performance on the vigilance test declined, though not to the deficient level of individuals who had been taking placebo at the first visit. As expected, those individuals taking ADDERALL XR at the second visit performed normally on the vigilance test. These findings suggest that there is a carryover beneficial effect of having performed a mentally demanding task in a competent and effective state that is still evident when the individual is not taking the medication.

About the Study

During the six-week study period, investigators randomized 15 patients to receive an initial three weeks of treatment with ADDERALL XR or a placebo, but neither investigators nor participants knew to which group they were assigned until the end of the study. At the end of this period, investigators switched the group taking ADDERALL XR to receive three weeks of placebo treatment, while the group taking a placebo crossed over to receive three weeks of ADDERALL XR. All participants were diagnosed with ADHD using the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TRâ) criteria. Participants received doses of ADDERALL XR at 20 milligrams (mg) for the first week and then increased to 40 mg and 50 mg for the second and third weeks, respectively.

Following a screening period, investigators tested all patients on the driving simulator at a practice visit (testing visit one) and after each three-week treatment period (testing visits two and three). Investigators measured driving performance at two, seven and 12 hours after participants took medication. The STISIM, a validated system, assesses critical driving skills, including situation awareness, hazard perception, risk assessment and decision-making under time pressure.

The majority of side effects during the trial were mild or moderate and consistent with known side effects of stimulant medications. The most common side effects reported by patients taking ADDERALL XR during the trial included decreased appetite, weight loss, dry mouth, insomnia and bruxism (teeth grinding). The most common side effects reported by patients taking placebo during the trial included decreased weight and headache.

Porter Novelli