TY  - JOUR
PY  - 1992//
TI  - Forced-choice versus free-choice procedures: caffeine self-administration in humans
JO  - Psychopharmacology
A1  - Oliveto, A. H.
A1  - Hughes, J. R.
A1  - Higgins, S. T.
A1  - Bickel, W. K.
A1  - Pepper, S. L.
A1  - Shea, P. J.
A1  - Fenwick, J. W.
SP  - 85
EP  - 91
VL  - 109
IS  - 1-2
N2  - Methodological comparisons of procedures for drug self-administration are rare. In studies examining the reinforcing effect of caffeine in humans, caffeine self-administration usually has been inferred from performance under forced-choice procedures. In the present experiment, caffeine self-administration via coffee was compared under forced-choice and free-choice conditions; i.e., when subjects were and were not required to use a minimum number of coffees. Ten moderate coffee drinkers (2-7 cups/day) were assigned to forced- and free-choice conditions using a randomized cross-over design. Under each choice condition, subjects completed six independent, double-blind trials, consisting of a 2-day exposure period followed by a 2-day test period. During exposure, subjects consumed either decaffeinated or caffeinated (100 mg/serving) coffee on day 1 and the other coffee on day 2. During the test period, subjects had concurrent access to the same decaffeinated and caffeinated coffees. Under the forced-choice condition, subjects were required to drink at least four cups of coffee per day during the test period. Under the free-choice condition, subjects did not have a minimum-cup requirement. In general, the relative rate at which subjects self-administered caffeinated versus decaffeinated coffee was similar across choice conditions, even though subjects self-administered significantly fewer cups of both coffee types under the free-choice than the forced-choice condition. These results suggest that, at least for caffeine, forced-choice and free-choice procedures produce comparable results. Whether this finding generalizes to a context in which caffeine or another drug is more robustly self-administered, remains to be determined.<p /> <p>Language: en</p>
LA  - en
SN  - 0033-3158
UR  - http://dx.doi.org/
ID  - ref1
ER  -