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1.2 Study hypotheses
A number of small scale studies were conducted in preparation for the main investigation and these are reported in Chapters 4, 5 and 6. Hypotheses for the main study, presented as null hypotheses, are:-
¨ Dependence, once established, does not diminish over time.
¨ Change in dependence cannot be predicted by pre-treatment demographic characteristics or
psychological and social functioning.
¨ Individuals with high dependence who change (in level of dependence or of use of the
substance) use the same coping strategies (cognitive/behavioural) and in the same degree as
individuals with low dependence who change.
¨ The measurement of impaired control, one component of dependence, has equal predictive
validity to the measurement of dependence.
1.3 Development of the concept of dependence
It is not the purpose of this section to replicate the histories of dependence theorising that have been written (for example see Jellinek 1960; Edwards 1992; Heather and Robertson 1983, 1997) but rather to examine the distinct conceptualisations in current thinking about the nature of dependence by way of explaining the background to the central concerns of the study. A number of classification systems for categorising the numerous and diverse explanatory frameworks are possible and it is difficult to find one that is comprehensive due to the cross-disciplinary nature of the field. For present purposes, the chosen classification system allows examination of major contributing theory and research wherein dependence is seen as:-
a) a disease state
b) a bio-psycho-social phenomenon and
c) a psychological phenomenon, whether substance specific or a general behavioural
phenomenon.
Disease theories of addiction and dependence are normally but not exclusively based in a biological understanding, whether the relevant biology is that of the person using the substance (as in those theories based in the idea that there is a physical predisposition to the development of dependence) or the pharmacological properties of the substance (as in those theories which suggest that some substances have certain properties which invariably and inevitably lead to their addictive
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