The Severity of Dependence Scale (SDS): psychometric properties of the SDS in English and Australian samples of heroin, cocaine and amphetamine users

The Severity of Dependence Scale (SDS) was devised to provide a short, easily administered scale which can be used to measure the degree of dependence experienced by users of different types of drugs. The SDS contains five items, all of which are explicitly concerned with psychological components of dependence. These items are specifically concerned with impaired control over drug taking and with preoccupation and anxieties about drug use. The SDS was given to five samples of drug users in London and Sydney. The samples comprised users of heroin and users of cocaine in London, and users of amphetamines and methadone maintenance patients in Sydney. The SDS satisfies a number of criteria which indicate its suitability as a measure of dependence. All SDS items load significantly with a single factor, and the total SDS score was extremely highly correlated with the single factor score. The SDS score is related to behavioural patterns of drug taking that are, in themselves, indicators of dependence, such as dose, frequency of use, duration of use, daily use and degree of contact with other drug users; it also shows criterion validity in that drug users who have sought treatment at specialist and non-specialist agencies for drug problems have higher SDS scores than non-treatment samples. The psychometric properties of the scale were good in all five samples, despite being applied to primary users of different classes of drug, using different recruitment procedures in different cities in different countries.

Nucleotide sequence and restriction fragment length polymorphism analysis of the long terminal repeat of human T cell leukemia virus type II

Molecular studies have demonstrated the existence of two major subtypes of human T cell leukemia virus type II: HTLV-IIa and HTLV-IIb. In attempts to further classify this family of viruses we have carried out nucleotide sequence and restriction fragment length polymorphism (RFLP) analysis of the long terminal repeat (LTR), a region that has been shown in previous studies to have the greatest intra- and intersubtype genomic divergence. Analysis of the nucleotide sequences suggested the existence of distinct phylogenetic groups in each subtype and, on the basis of predicted differences in restriction endonuclease sites, RFLP analysis allowed the identification of four groups within the IIa subtype (a1-a4) and six within the IIb subtype (b1-b6). Nucleotide sequence analysis also suggested the possible existence of HTLV-II quasispecies. However, this appeared not to be significant, and preliminary studies suggest that these would not be expected to influence the results of RFLP analysis appreciably. The validity of the RFLP method was demonstrated in an analysis of 36 randomly chosen samples from HTLV-II seropositive blood donors from the New York City Blood Center, where it could be shown that all could be successfully classified. Moreover, the RFLP analysis correctly matched the viruses in donors and recipients of contaminated blood in four situations in which HTLV-II was inadvertently transmitted by transfusion. RFLP analysis of the LTR appears to be a rapid and reliable method by which to identify HTLV-II infection. This should prove useful in studies of the epidemiology and the characterization of viruses present both in nonindigenous and indigenous populations.

Extraordinary high rate of HTLV type II seropositivity in intravenous drug abusers in south Vietnam

Serum specimens (n = 1899) were assayed for infections with HTLV-I, HTLV-II, and HIV-1 in seven classified groups of normal healthy controls, children, pregnant women, prostitutes, intravenous drug abusers, patients under going hemodialysis, and hemophiliacs in South and North Vietnam. Surprisingly, 125 of 954 samples from South Vietnam exhibited seropositivity for HTLV-II and 119 of these belonged to the group of IVDAs (n = 200). The remaining six positives were a healthy control, a prostitute, two children, and two patients under going hemodialysis. Two IVDAs who were seropositive for HTLV-I and 10 of 15 seropositives for HIV-1 were also positive for HTLV-II in this population. In contrast, no seropositives to any of the viruses were detected in the North Vietnamese samples (0 of 945). The HTLV-II-seropositive IVDAs exhibited increased seropositivity with age compared with HIV-1 seropositivity in the population, and there was no statistical relation between seropositivity for HTLV-II and HIV-1. The HTLV-IIs in South Vietnam IVDAs appeared, by subtype-specific peptide ELISA, to be a mixture of both subtypes a and b, with subtype a predominant. It seems possible that HTLV-II may have been introduced into this population from IVDAs from the United States during the Vietnam conflict, but in a period prior to, or early in, the introduction of HIV-1 to IVDAs.

A controlled trial of educational visiting to improve benzodiazepine prescribing in general practice

A randomised controlled trial studied the effect of an educational visit on benzodiazepine prescribing. An approximately representative sample of 286 general practitioners was allocated to an intervention or a control group. Rates of benzodiazepine prescriptions were derived from two comprehensive self-report surveys seven months apart. Two months after the first survey the intervention group received an educational visit and supporting material from a doctor or pharmacist, ostensibly unconnected with the surveys. The overall benzodiazepine prescribing rate fell by 23.7 per cent from the first to the second surveys, from 4.93 to 3.76 prescriptions per 100 encounters (P < 0.001). Anxiety and insomnia diagnosis rates also declined from 4.68 to 3.76 per 100 encounters (19.7 per cent). After adjusting for confounders, there was a differential downward trend in prescriptions per diagnosis of insomnia but not to a statistical level. The same was true of initial prescriptions per insomnia diagnosis. In a subsidiary analysis selecting only new insomnia diagnoses, the intervention had a strong effect in reducing initial prescriptions (odds ratio 0.18, 95 per cent confidence interval 0.04 to 0.73). No effect was seen on prescribing for anxiety diagnoses. Educational practice visiting for benzodiazepine prescribing in anxiety, as we conducted it, is not justified in an unselected population of general practitioners. Specific education on prescribing for insomnia is probably useful. Our interpretation of the reduction in benzodiazepine prescribing is that probably there was an effect from self-monitoring alone which overwhelmed a main-analysis intervention effect. Retrospective diagnosis may also have obscured a real intervention effect.

Quitting smoking: estimation by meta-analysis of the rate of unaided smoking cessation

The rates (after 12 months' follow-up) of unassisted smoking cessation reported in the literature have varied from 13.8 per cent to 8.5 per cent. A meta-analysis was conducted of the abstinence rates observed in 14 samples of smokers who presented at primary health settings and received either no intervention aimed at smoking or usual care (which involved no deliberate intervention for smoking cessation). The estimated rate of stopping smoking without intervention, over an average 10-month period, was 7.33 per cent. This rate is consistent with others reported in the literature when motivation to quit is taken into account. The estimate provides a baseline to judge the effects of smoking-cessation interventions.

Benzodiazepine prescribing in general practice: dispelling some myths

The objective was to analyse clinical and non-clinical factors associated with the receipt of a prescription for a benzodiazepine among general practice patients. A survey of 110 consecutive patient encounters (consultations) as recorded by a representative sample of general practitioners in inner urban, outer urban and rural settings was designed. A total of 286 general practitioners took part during 1991-2. 31,256 patients (10,683 male; 34%) were surveyed and the odds of receiving a benzodiazepine script measured. Insomnia, unlike anxiety, was almost routinely managed with a benzodiazepine alone (insomnia 89.6%; anxiety 49.4%), whereas anxiety was more likely to be managed with non-drug management (insomnia 7.2%; anxiety 38.3%). In multiple logistic regression, the variables significantly associated with the prescription of a benzodiazepine included being a female patient, being an older patient and being an established patient, who attends a GP working in a busy practice in an inner urban area. A second regression model was run with the addition of three variables, namely the presenting problems of anxiety and insomnia, and the number of health problems. The only predictors of benzodiazepine prescribing in the full model were these three clinical variables together with patient age. There is a need to educate doctors about the non-drug management of insomnia. The stereotype of the doctor over-prescribing a benzodiazepine without an appropriate problem/diagnosis should be questioned. On the other hand, there is concern that patient age continues to be associated with a prescription of these medications, when all other clinical and non-clinical factors are taken into account.

Injecting and sexual risk-taking behaviour among regular amphetamine users

A sample of 301 regular amphetamine users were interviewed regarding injecting and sexual risk-taking behaviours. Two-thirds of subjects were injecting the drug, with males being 1.8 times more likely to do so. Nearly half (41%) of injectors had shared injecting equipment in the preceding month. Females were twice as likely as males to report recent needle sharing. Having a regular sexual partner who injects amphetamines, using benzodiazepines and experiencing higher levels of psychopathology were independently associated with needle sharing. The number of sexual partners in the preceding six months was independently associated with having had paid sex in that period, and higher levels of polydrug use.

Methadone maintenance treatment in opiate dependence: a review

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Transitions between routes of administration of regular amphetamine users

A sample of 301 regular amphetamine users was interviewed regarding transitions between routes of administration of amphetamines. Use of amphetamines by injecting was widespread, with two-thirds (67%) of subjects having injected the drug during the preceding 6 months. Needle-sharing was common, with 41% of injectors having shared a needle in the month preceding interview. A transition to regular amphetamine injecting from other routes of administration was reported by 40% of subjects, with males being twice as likely to report such a transition. The median number of such transitions was one. The main reasons given by subjects for the transition to injecting were liking the "rush" from injecting, and seeing it as a more economical and a healthier way to use. A small proportion of subjects (9%) reported a transition away from injecting amphetamines, with a median of one such transition. The most common reason given for abandoning injecting was concern about vascular damage. Interventions to encourage safer use of amphetamines need to address the misconceptions that injecting is more economical and more healthy, and to emphasize the vascular problems associated with injecting.

Transmission of human T cell lymphotropic virus (HTLV) type II by transfusion of HTLV-I-screened blood products

Blood donors have been screened for antibodies to human T cell lymphotropic virus (HTLV) type I since December 1988. Screening for HTLV-II has been simultaneously done because of cross-reactivity between antibodies to the two viruses. Currently, < 1 in 10,000 US blood donors is positive for HTLV-I or -II. Lookback studies led to the identification of 6 HTLV-II-infected patients. Three received transfusions before introduction of HTLV-I screening tests, while the other 3 received blood components that tested negative for HTLV-I. The HTLV-II subtypes of each of 4 donor/recipient pairs, as determined by DNA amplification using polymerase chain reaction, were identical, supporting the view that transfusions were the source of infection. In conclusion, currently licensed blood donor screening tests for HTLV-I lack sensitivity for HTLV-II, and transfusion of blood from HTLV-II-infected donors that test negative on HTLV-I screening tests may result in infection.