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validation of the Leeds Dependence Questionnaire (Raistrick et al. 1994 see Appendix 1). The dimensionality of alcohol dependence was demonstrated by Skinner and Horn (1984) who showed that, for patients meeting the DSM-III criteria for alcohol abuse and dependence (American Psychiatric Association 1980), scores on the Alcohol Dependence Scale conform to a normal distribution demonstrating that there is, in this group, a broad range in the severity of dependence symptoms reported. The dependence scores of subjects not meeting the criteria for alcohol abuse and dependence showed a more skewed distribution.
Inclusion of the drug dependence syndrome in the two major classification systems (World Health Organisation 1981; American Psychiatric Association 1987) has resulted in several investigations of the nature, distinctness and validity of the concept. Hasin et al. (1988) examined the relationship between dependence syndrome symptoms and drug related disabilities to determine whether or not they constituted distinct dimensions as described in the original dependence syndrome formulation (World Health Organisation 1981). The participants in this study were patients receiving treatment for alcohol dependence and related problems who admitted to six or more lifetime incidents of use of any of a list of specific drugs: cannabis, stimulants, barbiturates, benzodiazepines, cocaine, opiates and hallucinogens. Dependence items were measured using a structured interview schedule, the Diagnostic Interview Schedule (Robins et al. 1981) comprising five dependence syndrome symptoms namely: i) feeling dependent on the drug, ii) unsuccessful attempts to cut down (impaired control), iii) tolerance, iv) withdrawal and v) daily use for two weeks or more (narrowing of the drug taking repertoire). While they found a high clustering of dependence items with each other, Hasin and her colleagues also found a high clustering with health, social and emotional problems related to substance misuse. This led them to propose that:
“All seven symptoms of the dependence syndrome as originally defined may be interpreted as stemming from the physiological process of withdrawal and from learning related to withdrawal avoidance. However, these physiological and learning processes may manifest themselves in all sorts of social, psychological, occupational and health symptoms and signs. The provisional formulation of the dependence syndrome leaves out the other
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