Page 81 - PhD GT

relate to conflict over the use of the drug: ‘Did you worry about your use of (named drug)?’ and ‘Did you wish you could stop?’ Item (v) refers to a perceived difficulty to stop use once started or to refrain from use, another impaired control item: ‘How difficult did you find it to stop, or go without (named drug)?’ The component they refer to as preoccupation is implicit, presumably in item (iii). Leaving out items that refer to tolerance, withdrawal and reinstatement (though why this last component is identified as being excluded is not clear), the authors claim, makes possible comparison across drug use that does and does not produce withdrawal.
This questionnaire has good psychometric properties when tested in five different samples of clinic attenders and community participants using heroin, cocaine or amphetamine (Gossop et al. 1995). Test-retest reliability was carried out on a different, single sample of heroin users attending the Maudsley Hospital for treatment of opiate dependence (Gossop et al. 1997). However, it has no face validity for alcohol dependence in its current form and indeed has not been used with this group. In addition to the concerns expressed above there are further concerns about the understanding of dependence which underpins the questionnaire in that respondents are instructed to respond “for the past year”. Is there an assumption that dependence is a lifetime phenomenon or at least that it would not change during the course of twelve months? If so, it is not clear over what period it is thought to change or whether change is less important than its ever having occurred? The rationale offered for questioning about the past year is “Since severity of dependence can be expected to vary over time...” (Gossop et al. 1992). It will be argued later, and shown in the results of the present study, that dependence is capable of changing over a three month period. If this is the case, it is unclear to what questioning about the past year refers.
The SDS has been used in a variety of clinical and community settings (Swift et al. 1998 for cannabis users; Topp and Darke 1997, Topp and Mattick 1997a for amphetamine users; De las Cuevas et al. 2000 and Ross et al. 1996 for benzodiazepine users; Gossop et al. 1994 for cocaine users; Strang et al. 1999 and Gossop et al. 1992 for heroin users). Being short and very simple to use, the SDS is an unintrusive measure. It has been used to compare severity of dependence with route of administration in heroin users (Strang et al.1999) but no data on predictive validity have been published. Its diagnostic utility has been demonstrated for amphetamine users (Topp and Mattick 1997b) and for cannabis users (Swift et al. 1998) supporting its use in place of a more detailed screening interview. De las Cuevas et al. (2000) recommend its use as a screening tool for the identification of benzodiazepine dependence in primary care rather than as a replacement for the more detailed assessment in the specialist setting. For the reasons stated above, coupled with the fact that it has not been adapted to or validated with an alcohol using population, it was not used in
69