Although patients with attention-deficit hyperactivity disorder (ADHD) have
reported improved driving performance on methylphenidate, limited evidence
exists to support an effect of treatment on driving performance and
some regions prohibit driving on methylphenidate. A randomized, crossover
trial examining the effects of methylphenidate versus placebo on highway
driving in 18 adults with ADHD was carried out. After three days of no
treatment, patients received either their usual methylphenidate dose (mean:
14.7mg; range: 10–30mg) or placebo and then the opposite treatment
after a six to seven days washout period. Patients performed a 100 km driving
test during normal traffic, 1.5 h after treatment administration.
Standard deviation of lateral position (SDLP), the weaving of the car, was
the primary outcome measure. Secondary outcome measurements included
the standard deviation of speed and patient reports of driving performance.
Driving performance was significantly better in the methylphenidate than in
the placebo condition, as reflected by the SDLP difference (2.3 cm, 95%
CI#1;0.8–3.8, P#1;0.004). Variation in speed was similar on treatment and on
placebo (#2;0.05 km/h, 95% CI#1;#2;0.4 to 0.2, P#1;0.70). Among adults with
ADHD, with a history of a positive clinical response to methylphenidate,
methylphenidate significantly improves driving performance.