A model of "overdose" deaths among heroin addicts is proposed which emphasizes recent findings concerning the contribution of drug-associated environmental cues to drug tolerance. Results of animal experiments performed to evaluate this model suggest that conditioned drug-anticipatory responses, in addition to pharmacological factors, affect heroin-induced mortality.

Prevalence of tobacco use among the college-aged population is approximately 30%; a significant percentage of students initiate use or transition to regular use during their college years. This study examined the relationship between drinking and smoking rates, subjective reactivity of concurrent effects of alcohol and tobacco use, and expectations of smoking while under the influence of alcohol in first-year college students. The sample consisted of ever-smokers (n=217), who had smoked at least once in the past year, with a mean age of 19.67 years. Weekly alcohol consumption was 18.53 standard drinks per week, with 2.95 drinking episodes per week. Of the sample, 54% were classified as smokers (smoked more than 100 cigarettes in their lifetime) and 46% were classified as experimenters (smoked less than 100 cigarettes in their lifetime). Results demonstrated that 74% of all smoking episodes occurred while under the influence of alcohol. Smokers had higher levels of alcohol use and reported greater subjective effects from the simultaneous use of alcohol and tobacco. Smokers also were more likely to generate expectancies acknowledging an increase in smoking while drinking and for smoking to enhance reinforcement from alcohol. Experimenters were most likely to report positive reinforcement from smoking while under the influence of alcohol. Overall, smokers experienced stronger subjective effects of concurrent alcohol and tobacco use; however, results suggest that smoking while under the influence of alcohol is a positive experience even for relatively inexperienced smokers.

Using an in vivo manipulation, this study examined whether alcohol outcome expectancies (AOEs) vary across environmental settings. Two hundred twenty-one undergraduates were randomly assigned to 1 of 4 conditions in which environmental context (an on-campus bar vs. a laboratory) and instructed phase of intoxication ("just enough to begin to feel intoxicated" vs. "too much to drink") were manipulated. AOEs were assessed with a revised version of the Effects of Alcohol Scale (L. Southwick, C. Steele, A. Marlatt, & M. Lindell, 1981). Compared with participants tested in the laboratory, individuals exposed to the on-campus bar expected greater alcohol-related stimulation/perceived dominance and pleasurable disinhibition. Women expected more behavioral impairment during the latter stage of intoxication. These findings highlight the importance of ecologically valid research in this area, as well as cue-exposure assessment and treatment approaches.

Preconditioning experience with the unconditional stimulus (UCS) retards subsequent excitatory conditioning. Three experiments demonstrated that this UCS retardation effect is attenuated by associative manipulations of contextual stimuli of the UCS preexposure environment. The UCS retardation effect was reduced by (a) altering contextual stimuli between preexposure and conditioning (Experiment 1), (b) latently inhibiting contextual stimuli prior to UCS preexposure (Experiment 2), and (c) extinguishing contextual stimuli subsequent to UCS preexposure (Experiment 3). Although UCS preexposure retarded excitatory conditioning, the results of Experiment 4 demonstrated that UCS preexposure facilitated inhibitory conditioning. These results indicate that an association between contextual stimuli and the preexposed UCS contributes to the effects of preconditioning UCS experience on subsequent learning.

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