SUBJECTIVE EFFECTS OF ORAL CAFFEINE IN FORMERLY COCAINE-DEPENDENT HUMANS

Eleven formerly cocaine-dependent (FCD) adults (mean 4 years in recove ry) and 11 with no substance dependence history (ND) drank one cup of coffee (caffeine content 0, 50, or 100 mg) per hour for 5 h (for a tot al of 0, 250, or 500 mg caffeine) in a double-blind, randomized crosso ver procedure. Participants completed self-report scales before the fi rst cup and 50 min after each cup. Caffeine did not increase cocaine-l ike effect or desire-for-cocaine ratings among the FCD subjects. Ratin gs of 'jittery' (P < 0.05) and 'anxious/tense/nervous' (P < 0.10) incr eased more with caffeine in the FCD group than among ND subjects. Self -report measures of caffeine reinforcement did not differ between FCD and ND groups. These results suggest that, among FCD adults, (a) caffe ine does not produce cocaine-like effects, Cb) caffeine reinforcement is neither greater nor lesser than that among ND adults, and (c) chron ic cocaine use may induce sensitization to some effects of stimulants. (C) 1997 Elsevier Science Ireland Ltd.