Stimulant effects of 3,4‐methylenedioxymethamphetamine (MDMA) 75 mg and methylphenidate 20 mg on actual driving during intoxication and withdrawal

ABSTRACT Background 3,4‐methylenedioxymethamphetamine (MDMA) is currently one of the most popular drugs of abuse in Europe. Its increasing use over the last decade has led to concern regarding possible adverse effects on driving. The aims of the present study were to investigate the acute effects of MDMA on actual driving performance during the intoxication and withdrawal phase.

Methods: Eighteen recreational MDMA‐users (nine males, nine females) aged 21–39 years participated in a double‐blind, placebo‐controlled, three‐way cross‐over study. MDMA 75 mg, methylphenidate 20 mg and placebo were administered on day 1 of treatment (intoxication phase). Driving tests were conducted between 3 and 5 hours post‐drug. Subjects returned the following day for a repetition of the driving tests between 27 and 29 hours post‐drug (withdrawal phase). On‐the‐road driving tests consisted of a road‐tracking test and a car‐following test. Its main parameters were standard deviation of lateral position (SDLP), time to speed adaptation (TSA), brake reaction time (BRT) and gain.

Findings: MDMA and methylphenidate significantly decreased SDLP in the road‐tracking tests by about 2 cm relative to placebo on day 1 (intoxication phase). In addition, MDMA intoxication decreased performance in the car‐following test as indicated by a significant rise in the ‘overshoot’ of the subjects’ response to speed decelerations of the leading vehicle. Driving performance was not affected by treatments during withdrawal on day 2.

Conclusion: Collectively, these data indicate that MDMA is a stimulant drug that may improve certain aspects of the driving task, such as road‐tracking performance, but may reduce performance in other aspects of the driving task, such as accuracy of speed adaptation during car‐following performance.