Table 1.

Characteristics of the subjects of the different groups

	Subjects (males/females)	Age	Weight
Group 1 (natural history)	48  (26/22)	38.2  ± 8.5	63.4  ± 10.8
Group 2 (hidden naloxone)	20  (10/10)	36.1  ± 7.6	63.8  ± 7.8
Group 3 (placebo on left hand)	25  (13/12)	40.4  ± 9.8	59.7  ± 9.5
Group 4 (placebo on left hand plus naloxone)	27  (13/14)	36.7  ± 8.8	60.1  ± 11.4
Group 5 (placebo on right hand and left foot)	24  (12/12)	39.0  ± 7.6	65.2  ± 11.0
Group 6 (placebo on right hand and left foot plus naloxone)	29  (16/13)	37.5  ± 9.1	61.9  ± 8.4