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the current attitude change to this behaviour at the societal level resulted in higher levels of smoking cessation accounted for by the diminished expected utility of the behaviour (the greater expectation of resulting illness).
With reference to the drug dependence syndrome, Edwards (1986) emphasised that the alcohol dependence syndrome formulation “carried with it no assumptions as to whether the condition was progressive or irreversible” (p. 172) but the component of rapid reinstatement after a period of abstinence carries the suggestion of a condition which is permanent. Whether this marker of dependence refers to the permanence of a physiological state or to the reinstatement of previously learned behaviour which has been conditioned by this underlying physiological state and which has not been extinguished, observation of the behaviour pattern supported the popular idea that there was no such thing as controlled use following the development of dependence (see for example Heather and Robertson 1997).
A number of animal and human studies show the resilience of the conditioned responses to extinction over time (Childress et al. 1986; Siegel 1988; Logan 1993) while other studies suggest that levels of dependence fluctuate in both directions. For example community studies have shown that rates of dependence at one time do not predict rates of dependence at a subsequent time, leading to the assertion of spontaneous remission from alcoholism (Saunders and Kershaw 1979; Polich et al. 1981; Vaillant 1983). Robins (1978) demonstrated the effect of a change in the environment on rates of heroin use and dependence in her study of Vietnam war veterans returning to the United States. The relapse rate post detoxification in her sample was in the region of 7%, and long term follow-up identified the ability of respondents who had previously been addicted to heroin in Vietnam to use on an occasional, recreational basis without becoming re-addicted.
Laboratory experiments have shown the ability of patients diagnosed as alcoholics to exercise control over their consumption in the anticipation of relatively more highly valued rewards (Mello et al. 1968) thus suggesting that the behaviour of these individuals is subject to the same sorts of reinforcement as the general population and if this is the case then their behaviour should theoretically be able to be learned and extinguished by the same principles. The subjective experiences of craving and impaired control have been shown to be reduced in patients diagnosed as alcoholics following cue exposure procedures in the psychological laboratory (Rankin and Hodgson 1976).
Thus many findings refute assumptions of permanence and irreversibility, but studies have tended to focus on the question of whether dependence predicts future drug use rather than looking at whether and how the dependent state itself changes. It is one of the objectives of the present
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