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and on this basis, the null hypothesis can be rejected.
A contribution of this thesis to the body of research on dependence is the measurement of
dependence as the principal change measure in a clinic attending population. Preliminary studies investigated further the psychometric properties of the LDQ and demonstrated its ability to measure dependence in abstinence. In the main study, the instrument was shown to be capable of measuring changes over time.
Two instruments, which were developed for measurement in problem drinkers, were adapted for use with heroin users; adaptation and validation of these instruments was also part of the preliminary work in the present thesis. As increasing emphasis is placed upon the commonalities in dependence across the different substances, and treatment agencies begin to combine treatments for dependence on different substances, there is a concurrent need to have available measurement instruments which are capable of measuring the same psychological phenomena across substance using groups.
10.1.1 Dependence declines over time
Dependence as measured by the LDQ was shown to decline over time. A method of determining the extent to which such decline was reliably measured and was clinically significant was applied. Thus it was possible to attribute different levels of meaning to the findings regarding degrees of change in dependence as well as to assert with confidence when such changes had occurred. The application of these criteria contribute to the body of research on outcomes in substance dependence which has tended to focus on measuring change in use and in substance related problems and to which the criteria for reliability and clinical significance have not been applied.
As described in Chapter 1, there are different ways of looking at dependence. Some view dependence as that which determines the nature and pattern of use, while others view use of the substance as that which determines dependence. The relationships between use and dependence were examined and found to be correlated but not perfectly. Dependence was shown to endure once use of the substance had ceased and it may be that it is the endurance of the conditioned responses which constitute the dependent behaviour which are both measured and responsible for the frequency of relapse.
10.1.2 The nature of change
The treatment literature is replete with references to the application of coping strategies for 215