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PhD Thesis - Rees, V.W

Cue reactivity in tobacco smokers: the role of Pavlovian conditioning in drug dependence phenomena
Rees V W (1996)

Abstract:
Research into mechanisms for drug dependence phenomena has yielded considerably evidence that Pavlovian conditioning plays an important role. One of the most widely abused and harmful drugs, nicotine, has been shown to produce classic phenomena of dependence, including habitual usage, tolerance, craving, withdrawal and relapse. The present thesis examined the role of Pavlovian conditioning in drug dependence phenomena, using nicotine as a model for drug dependence. The extent to which subjective and physiological indices of cue reactivity constitute a Pavlovian conditioned response was investigated, using cue reactivity as an investigative tool. The role of certain key factors in drug conditioning, such as cue characteristics, methods of response measurement, level of dependence, smoking history, and smoking motives were explored.

The validity of the method used to measure urge to smoke was established in a study of urge concomitants, in Chapter 6. The experiments reported in Chapters 7 and 8 explored the associative nature of cue reactivity in heavy and non-dependent smokers, and addressed key issues in the determination of the cue-elicited response, including differential reactivity, and the role of cue reactivity in acute tolerance. Cue reactivity in non-dependent smokers was examined in Chapter 8, and correlates of subjective urge reactivity, including physiological and behavioural responses, were explored. The role of individual difference measures in cue reactivity was investigated in Chapter 9. Finally, the role of cue reactivity in mediating treatment outcome, and measurement of changes in cue reactivity as a consequence of treatment, were addressed in Chapter 10.

The results of these investigations demonstrated that exposure to nicotine cues influenced certain phenomena of nicotine dependence, including craving, acute tolerance, nicotine use, and treatment outcome. These data suggested that cue reactivity has an associative basis, involving elements of Pavlovian conditioning, and support models which propose that conditioned drug cue reactivity influences drug dependence phenomena. The results indicated that only physiological responses were adequately explained by principles of Pavlovian conditioning theory. Self-reported urge reactivity appeared to function independently of physiological reactivity, and may involve some degree of higher cognitive processing. Physiological reactivity was more closely related with actual nicotine use, cue-elicited tolerance, and treatment outcome, than subjective urge reactivity.

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