The purpose of this study is to determine whether motorcycle drivers with ADHD are at a greater risk for motorcycle accidents, and whether this risk can be mitigated by treatment with methylphenidate. We will evaluate the effectiveness of Methylphenidate on driving performance, among motorcycle drivers, and investigate the correlation between improvement of ADHD symptoms (inattention and impulsivity) and driving performance.

Traffic accidents (car and motorcycle) are the second leading cause of death in 15-34 year-old males. Within this group, the prevalence of motorcycle accidents is currently increasing at a significantly higher rate than the prevalence of car accidents, and studies in the international literature suggest that motorcycle drivers comprise a distinct driver profile to car drivers. Motorcycles are, by design, more difficult to control, and lend themselves more to performing dangerous stunts. Mistakes and lapses in judgment are likely to have more severe consequences when motorcycles are involved, especially when one considers the exposed nature of the driver. This is of special concern in Brazil, where a large population of so called "motoboys" delivers almost everything upon request, from food to work documents.

It is well known that individuals with ADHD have more traffic problems, such as: a higher risk of a car accident; more violent crashes; more traffic violations and a greater chance of losing the driver's license. On a driving simulator, subjects with ADHD usually present with more errors and crashes, in comparison to normal controls. Treatment with Methylphenidate (MPH), however, has been shown to improve driving performance on the simulator (For example, subjects significantly reduce their speed when necessary as compared to a placebo group), and this in turn is a good indicator of better real-life driving performance.

At present, there are no studies on the effect of ADHD treatment with MPH specifically on motorcycle drivers. This is relevant, since the increasing prevalence of traffic accidents can attributed to increased incidence of motorcycle accidents. If the treatment proves effective, this study will contribute to a reduction in a major social and health concern.

Inclusion Criteria:

• Professional Motorcycle Driver
• Current diagnosis of ADHD

Exclusion Criteria:

• Mental retardation
• ADHD treatment in the last month
• Psychosis