Effects of d-amphetamine on simulated driving performance before and after sleep deprivation.
BACKGROUND
Stimulant drugs are commonly abused and also used to promote wakefulness, yet their effects on driving performance during sleep deprivation have not been thoroughly researched in experimental studies.


OBJECTIVE
The aims were to assess the effects on fundamental driving parameters during simulated driving of two doses of d-amphetamine and further to assess the interaction between d-amphetamine and sleep deprivation.


METHODS
A double-blind, placebo-controlled experiment including 18 healthy male volunteers was conducted.


RESULTS
The participants felt more alert when taking a dose of d-amphetamine than when taking placebo, and the effect was stronger for the higher dose. However, the data did not show any evidence that taking d-amphetamine prevented the subjects from becoming successively sleepier during the night. A significant main effect of the dose was found for three out of the five primary indicators where the lower dose led to improved driving. These indicators were crossing-car reaction time, and coherence and delay from a car-following event. Regarding sleep deprivation, a main effect was found for four of the primary indicators and three of the secondary indicators. The results showed overall impaired driving with respect to standard deviation of lateral position and delay in reaction time when the sleep-deprived conditions were compared to the alert condition. We found no interactions between dose and sleep deprivation for any of the performance indicators.


CONCLUSIONS
Our results suggest that administration of d-amphetamine does not compensate for impairment of driving due to fatigue. The positive effects of 10 mg were not further improved or even sustained when increasing the dose to 40 mg.
Swedish Road and Transport Research Institute, SE-581 95 Linköping, Sweden. magnus.hjalmdahl@vti.se
Magnus
M
Hjälmdahl
Anna
A
Vadeby
Asa
A
Forsman
Carina
C
Fors
Gunnel
G
Ceder
Per
P
Woxler
Robert
R
Kronstrand
D000328:Adult; D001334:Automobile Driving; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D003913:Dextroamphetamine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D006801:Humans; D008297:Male; D011597:Psychomotor Performance / Q000187:drug effects*; D012890:Sleep / Q000187:drug effects; D012892:Sleep Deprivation / Q000523:psychology*; D011795:Surveys and Questionnaires
D000697:Central Nervous System Stimulants; D003913:Dextroamphetamine