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Biomedical subjects

W Hall

Publications and source records attributed to W Hall.

At least 73 records · Page 4Linked to original sources
PubMed1998

A mathematical model of HIV transmission in NSW prisons.

A mathematical model was developed to estimate HIV incidence in NSW prisons. Data included: duration of imprisonment; number of inmates using each needle; lower and higher number of shared injections per IDU per week; proportion of IDUs using bleach; efficacy of bleach; HIV prevalence and probability of infection. HIV prevalence in IDUs in prison was estimated to have risen from 0.8 to 6.7% (12.2%) over 180 weeks when using lower (and higher) values for frequency of shared injections. The estimated minimum (and maximum) number of IDU inmates, infected with HIV in NSW prisons was 38 (and 152) in 1993 according to the model. These figures require confirmation by seroincidence studies.

Databases, Factual↗
PubMed1998

Choosing a diagnostic cut-off for cannabis dependence.

AIM: While cannabis dependence has been increasingly recognized, there is little research on the measurement issues involved in operationalizing the dependence syndrome for this drug. This paper aimed to investigate the diagnostic utility and appropriate diagnostic cut-offs of three short dependence measures among long-term cannabis users. SETTING AND PARTICIPANTS: Two hundred long-term, regular cannabis users were recruited and interviewed in Sydney, Australia. MEASUREMENTS: Receiver Operating Characteristic analyses compared the diagnostic performance of the short University of Michigan CIDI, a measure of ICD-10 dependence and the Severity of Dependence Scale against the "gold standard" of moderate or more severe DSM-III-R cannabis dependence, as diagnosed by the Substance Abuse Module of the CIDI. FINDINGS: The measures were of equal utility in diagnosing at least moderate DSM-III-R cannabis dependence. While the optimal diagnostic cut-offs for the short University of Michigan CIDI and the ICD-10 dependence measure remained unchanged from those conventionally applied, a more liberal cut-off was optimal for the Severity of Dependence Scale. The amended prevalence of cannabis dependence was 77% using the short University of Michigan CIDI, 72% by the ICD-10 measure and 62% by the Severity of Dependence Scale. CONCLUSIONS: The three instruments were able to diagnose cannabis dependence at levels substantially better than chance. They were generally robust in terms of the optimal diagnostic cut-off in a population of long-term cannabis users. This paper provides guidelines for choosing optimal cut-offs within different contexts.

Adolescent↗
PubMed1998

Long-term cannabis use: characteristics of users in an Australian rural area.

AIM: To investigate the characteristics and patterns of cannabis and other drug use among long-term cannabis users in an Australian rural area. DESIGN: Cross-sectional survey of a "snowball" sample of long-term cannabis users. SETTING: The North Coast of New South Wales is an area with high levels of cannabis cultivation and use, and many long-term users. PARTICIPANTS: The study involved 268 long-term cannabis users who had regularly used cannabis for at least 10 years. MEASUREMENTS: A structured interview schedule obtained information on: demographics, social circumstances, patterns of cannabis and other drug use, contexts of use, perceptions about cannabis and legal involvement. FINDINGS: The mean age of the sample was 36 years and 59% were made. The median length of regular cannabis use was 19 years. Most (94%) used two or more times a week and 60% used daily, with a median of two joints per day. Two-thirds (67%) used cannabis in social settings and two-thirds grew cannabis for their own use. The most common reasons for using cannabis were for relaxation or relief of tension (61%) and enjoyment or to feel good (27%). The most commonly reported negative effects were feelings of anxiety, paranoia, or depression (21%), tiredness, lack of motivation and low energy (21%) and effects of smoke on the respiratory system (18%). The majority drank alcohol (79%) and over one-third were drinking at hazardous levels. Most were current (64%) or ex-tobacco smokers (24%). One-quarter (25%) had been charged with possession of cannabis, 11% for cultivation and 6% for supply, with non-drug offences low (8%or less). Overall, three-quarters (72%) believed that the benefits of cannabis use outweighed the risks, 21% felt there was an even balance, and 7% said cannabis had done them more harm than good. CONCLUSIONS: Among long-term cannabis users in this Australian rural area, cannabis use was an integral part of everyday life and it was primarily used in social situations for the same reasons that alcohol use is used in the wider community.

Adult↗
PubMed1998

Patterns and correlates of cannabis dependence among long-term users in an Australian rural area.

AIM: To examine prevalence and correlates of cannabis dependence among long-term cannabis users. DESIGN: A cross-sectional survey of patterns and experiences of cannabis use and dependence. SETTING AND PARTICIPANTS: A snowball sample of 243 long-term cannabis smokers, who were currently smoking 3-4 times a week, were recruited from the New South Wales North Coast, an area long associated with cannabis cultivation and use. MEASUREMENTS: A structured interview was administered, incorporating the following dependence measures: an approximation to a life-time DSM-III-R diagnosis, an approximation to a 12-month ICD-10 diagnosis, and the Severity of Dependence Scale (SDS). FINDINGS: Prevalence of a life-time DSM-III-R diagnosis of cannabis dependence was 57%, while 57% received an ICD-10 dependence diagnosis for the last year. Substantially fewer (15%) of the sample were diagnosed as dependent according to the Severity of Dependence Scale (SDS). Only 26% believed they had a problem with cannabis at least sometimes. There was general concordance between DSM-III-R and ICD-10 measures, but not between these and the SDS. ICD-10 and DSM-III-R dependence diagnoses were modestly correlated with age, life-time illicit drug use and quantity of cannabis use. Principal components analyses of the dependence measures provided little evidence for a unidimensional dependence syndrome for ICD-10 and DSM-III-R criteria. There was strong support for unidimensionality of the SDS. CONCLUSIONS: Symptoms of cannabis dependence were common among these long-term users but only one-quarter perceived that they had a cannabis problem. There was no strong evidence for a unidimensional cannabis dependence syndrome.

Cross-Sectional Studies↗
PubMed1998

An evaluation of Cloninger's typology of alcohol abuse.

AIMS: To evaluate Cloninger's typology of "alcoholism" using the Alcohol Symptom Scale (Gilligan et al., 1987). PARTICIPANTS: A sample of 300 Australian men and women with a life-time diagnosis of DSM-III-R alcohol abuse/dependence. MEASURES: The Alcohol Dependence Scale, the Short Alcoholism Screening Test, the Composite International Diagnostic Interview (CIDI) Substance Abuse Module, the Brief Symptom Inventory, the CIDI core modules, the Family History Questionnaire and the Sensation Seeking Scale. FINDINGS: The Alcohol Symptom Scale classified only 18% of the sample into either type 1 or type 2. There was mixed support for the hypothesized differences between type 1 and type 2 problem drinkers in pattern of alcohol abuse, gender, personality characteristics and familial aggregation of alcohol abuse. More women than men were classified as type 1 (19% vs. 6%) but, contrary to expectations, similar numbers were classified as type 2 problem drinkers (7% vs. 4%). As predicted, type 2 problem drinkers had more symptoms of antisocial personality disorder, more social consequences of drinking and higher sensation-seeking scores than type 1 problem drinkers. CONCLUSIONS: Cloninger's typology failed to classify two types of problem drinkers and it did not predict gender differences in symptoms of alcohol dependence, family history or personality. Schuckit, Irwin & Mahler's (1990) hypothesis that type 2 problem drinkers are more likely to have primary ASPD was supported.

Adult↗
PubMed1998

Nursing's metaparadigm concepts: disimpacting the debates.

Theoretical advances in nursing have been complicated by polarization and extreme positions regarding nursing's approach to its main metaparadigm concepts: person, health, environment and nursing. In this paper, the authors deconstruct some of the central arguments that are used to further this polarization. Using a critical interpretive approach, they explain some of the logical implications imposed by various extreme positions for the larger project of nursing's health and social mandate, and consider the effects of such polarization. On the basis of an appreciation of the serious difficulties inherent in certain philosophical and theoretical positions currently evident within nursing's literature, the authors argue for a less extreme and more integrated reference point for nursing's theory and practice.

Disease↗
PubMed1998

Jurisdictional trends in opioid overdose deaths, 1988-96.

This report analysed data on opioid overdose mortality between 1988 and 1996 to: examine differences between jurisdictions in the rate of fatal opioid overdose and the rate of increase in overdose; and estimate the proportion of all deaths which were attributed to opioid overdose. Australian Bureau of Statistics (ABS) data were obtained on the number of deaths attributed to opioid dependence (ICD 9 codes 304.0, 304.7) and accidental opioid poisoning (ICD 9 codes E850.0, E850.1). The highest rate of fatal overdose occurred in NSW, followed by Victoria. The standardised mortality rate among other jurisdictions fluctuated quite markedly. While the rate of opioid overdose has increased throughout Australia, the rate of increase has been greater in some of the less-populous states and territories than it has in NSW or Victoria. In 1996, approximately 6.5% of all deaths among people aged 15-24 years and approximately 10% of all deaths among those aged 25-34 were due to opioid overdose. During the interval from 1988 to 1996, the proportion of deaths attributed to opioid overdose increased. From 1988 to 1996, the proportion of deaths attributed to opioid overdose among individuals aged 25-34 years was approximately one-third that attributed to suicide, but this proportion had increased to approximately one-half by 1996. The rate of increase in the proportion of deaths attributed to opioid overdose was higher than the rate of increase in the proportion of deaths attributed to suicide.

Adolescent↗
PubMed1998

Characteristics of long-term cannabis users in Sydney, Australia.

Two hundred long-term cannabis users (58% male) were interviewed on their characteristics and experience of use. Respondents had been regularly using cannabis for an average of 11 years and more than half used daily (56%). The most common route of administration was in a waterpipe, and nearly all (93%) smoked the flowering heads ot the plant. One in 5 (21%) had a cannabis-related conviction. The benefits of use were perceived to be its relaxing, mood-enhancing effects, and its ability to alter consciousness. The most commonly cited negative aspects of use were cost, negative psychological effects and legal status. Polydrug use was common, with alcohol and tobacco almost universally used on a regular basis. More than half the drinkers in the sample were consuming alcohol at hazardous or harmful levels.

Adolescent↗
PubMed1998

Factor structure of psychopathy among methadone maintenance patients.

The proposed two-factor structure of the Psychopathy Checklist (Revised) was assessed by confirmatory factor analyses on a sample of 376 community and prison based methadones maintenance patients. Confirmatory factor analyses indicated that the two-factor model proposed by previous researchers did not fit well with the data from this population. Exploratory analyses extracted five interpretable factors, three psychological factors (glibness/manipulative, callousness, irresponsibility), and two behavioral factors (criminal behaviors, promiscuity), which accounted for 61% of the variance. The data provided support for the psychometric reliability of the PCL-R, as indicated by a Chronbach's alpha of 0.83, weighted kappas for concordance between raters ranging from 0.51 to 1.00, and 100% agreement on diagnoses of psychopathy between raters. The data indicate that a two-factor structure does not adequately capture the dimensions of psychopathy in this population. While the factors do fall into distinct psychological and behavioral dimensions, more than two general factors are required to describe the dimensions of psychopathy.

Adult↗
PubMed1997

Amphetamine-related harms and treatment preferences of regular amphetamine users in Sydney, Australia.

Amphetamines remain a popular illicit drug among young adults in Australia and a number of other countries, particularly by injection. A significant increase in the number of people presenting to drug treatment services with a primary amphetamine problem in Australia and the US has occurred in recent years. A survey of 200 regular amphetamine users was conducted in Sydney to determine the treatment issues and preferences of this population. Substantial harm associated with the use of this drug was found, most notably psychological problems, physical health problems, dependence and financial problems. A perceived need for amphetamine-specific treatment was evident. Popular treatment options requested by users included pharmacotherapies, natural therapies and counselling. While regular amphetamine users can attend existing treatment services, the efficacy of these treatments for amphetamine problems has not been evaluated. There is also a need to develop and evaluate amphetamine-specific interventions in order to attract this population into treatment.

Adolescent↗
PubMed1997

Methadone maintenance and drug-related crime.

Using data from an evaluation of methadone maintenance treatment, this study investigated factors associated with continued involvement in crime during treatment, and in particular whether there appeared to be differences in effectiveness of treatment between different methadone clinics. The methodology was an observational study, in which 304 patients attending three low-intervention, private methadone clinics in Sydney were interviewed on three occasions over a twelve month period. Outcome measures were self-reported criminal activity and police department records of convictions. By self-report, crime dropped promptly and substantially on entry to treatment, to a level of acquisitive crime about one-eighth that reported during the last addiction period. Analysis of official records indicated that rates of acquisitive convictions were significantly lower in the in-treatment period compared to prior to entry to treatment, corroborating the changes suggested by self-report. Persisting involvement in crime in treatment was predicted by two factors: the cost of persisting use of illicit drugs, particularly cannabis, and ASPD symptom count. Treatment factors also were independently predictive of continued involvement in crime. By both self-report and official records, and adjusting for subject factors, treatment at one clinic was associated with greater involvement in crime. This clinic operated in a chaotic and poorly organized way. It is concluded that crime during methadone treatment is substantially lower than during street addiction, although the extent of reduction depends on the quality of treatment being delivered.

Adult↗