Table 1

Experimental design

SessionDrugDoses (mg/70 kg)
Dose run-up sessions1-a 1Caffeine0, 100, and 200
2Caffeine0 and 400
3Nicotine0, 0.75, and 1.5
4Nicotine0 and 3.0
Experimental sessions1-b 5Caffeine200
6Nicotine1.5
7Caffeine400
8Nicotine0.75
9Nicotine3.0
10Placebo0.0
11Caffeine100

An example of the sequence of drug conditions for the dose run-up and experimental sessions.

    • ↵1-a  Half the subjects received the caffeine dose run-up first, and the other subjects received the nicotine dose run-up first.

    • ↵1-b  An example of a mixed drug and dose order.