Shane Darke

Self-report among injecting drug users: A review

The use of behavioural self-reports of drug users is widespread among studies of illicit drug use. Despite widespread use, concerns about the accuracy of these reports continue to be raised. The current paper critically reviews the literature on the reliability and validity of self-reported drug use, criminality and HIV risk-taking among injecting drug users. The literature shows respectable reliability and validity of self-reported behaviours when compared to biomarkers, criminal records and collateral interviews. It concludes that the self-reports of drug users are sufficiently reliable and valid to provide descriptions of drug use, drug-related problems and the natural history of drug use.

Major physical and psychological harms of methamphetamine use

ISSUES The major physical and psychological health effects of methamphetamine use, and the factors associated with such harms. APPROACH Comprehensive review. KEY FINDINGS Physical harms reviewed included toxicity and mortality, cardiovascular/cerebrovascular pathology, dependence and blood-borne virus transmission. Psychological harms include methamphetamine psychosis, depression, suicide, anxiety and violent behaviours. IMPLICATIONS While high-profile health consequences, such as psychosis, are given prominence in the public debate, the negative sequelae extend far beyond this. This is a drug class that causes serious heart disease, has serious dependence liability and high rates of suicidal behaviours. CONCLUSION The current public image of methamphetamine does not portray adequately the extensive, and in many cases insidious, harms caused.

A review of drug use and driving: epidemiology, impairment, risk factors and risk perceptions

The existing literature on the prevalence of drug driving, the effects of drugs on driving performance, risk factors and risk perceptions associated with drug driving was reviewed. The 12-month prevalence of drug driving among the general population is approximately 4%. Drugs are detected commonly among those involved in motor vehicle accidents, with studies reporting up to 25% of accident-involved drivers positive for drugs. Cannabis is generally the most common drug detected in accident-involved drivers, followed by benzodiazepines, cocaine, amphetamines and opioids. Polydrug use is common among accident-involved drivers. Studies of impairment indicate an undeniable association between alcohol and driving impairment. There is also evidence that cannabis and benzodiazepines increase accident risk. The most equivocal evidence surrounds opioids and stimulants. It is apparent that drugs in combination with alcohol, and multiple drugs, present an even greater risk. Demographically, young males are over-represented among drug drivers. Although there is an association between alcohol use problems and drink driving, it is unclear whether such an association exists between drug use problems and drug driving. Evidence surrounding psychosocial factors and driving behaviour is also equivocal at this stage. While most drivers perceive drug driving to be dangerous and unacceptable, there is less concern about impaired driving among drug drivers and drink drivers than from those who have not engaged in impaired driving. Risk perceptions differ according to drug type, with certain drugs (e.g. cannabis) seen as producing less impairment than others (e.g. alcohol). It is concluded that drug driving is a significant problem, both in terms of a general public health issue and as a specific concern for drug users.

Heroin overdose: research and evidence-based intervention.

Drug overdose is a major cause of premature death and morbidity among heroin users. This article examines recent research into heroin overdose to inform interventions that will reduce the rate of overdose death. The demographic characteristics of overdose cases are discussed, including factors associated with overdose: polydrug use, drug purity, drug tolerance, routes of administration, and suicide. Responses by heroin users at overdoses are also examined. Potential interventions to reduce the rate of overdose and overdose-related morbidity are examined in light of the emerging data in this field.

The reliability and validity of a scale to measure Hiv risk-taking behaviour among intravenous drug users

The initiation and maintenance of substantial behaviour change is required to reduce the spread of HIV infection among the intravenous drug-using population. In order to ascertain the efficacy of interventions aimed at reducing HIV-related risk-taking behaviour among this population, valid and reliable (yet preferably short) instruments for measuring such behaviour are required. The HIV risk-taking behaviour scale (HRBS) is a brief 11-item interviewer-administered scale which examines the behaviour of intravenous drug users in relation to both injecting and sexual behaviour. This paper describes the construction of the scale, in addition to data evaluating its reliability and validity. Initial analyses indicate that the scale has satisfactory psychometric properties.

The characteristics of heroin users entering treatment: findings from the Australian treatment outcome study (ATOS)

The current study aimed to describe the characteristics (demographics, drug use, mental and physical health) of entrants to treatment for heroin dependence in three treatment modalities; and to compare these characteristics with heroin users not in or seeking treatment. Participants were 825 current heroin users recruited from Sydney, Adelaide and Melbourne: 277 entering methadone/buprenorphine maintenance treatment (MT), 288 entering detoxification (DTX), 180 entering drug-free residential rehabilitation (RR) and 80 not in treatment (NT). Treatment entrants were generally long-term heroin users with previous treatment experience. The majority of the sample (55%) were criminally active in the month preceding interview. Injection-related health problems (74%) and a history of heroin overdose (58%) were commonly reported. There were high degrees of psychiatric co-morbidity, with 49% reporting severe psychological distress, 28% having current major depression, 37% having attempted suicide and 42% having a lifetime history of post-traumatic stress disorder. Personality disorders were also prevalent, with 72% meeting criteria for antisocial personality disorder and 47% screening positive for borderline personality disorder. Striking similarities were noted between the non-treatment and treatment groups in length of heroin use career, drug use and treatment histories.

Polydrug dependence and psychiatric comorbidity among heroin injectors

The prevalence of diagnoses of substance dependence, anxiety disorders and depressive disorders were estimated in a sample of 222 heroin injectors, using the Composite International Diagnostic Interview. Subjects had a median of three lifetime substance diagnoses and two current diagnoses. A total of 60% met the criteria for a lifetime anxiety disorder, and 51% had a current anxiety disorder. A depressive disorder was diagnosed in 41% of subjects, with 30% having a current diagnosis. There were significant positive correlations between the number of lifetime drug dependence diagnoses and the number of lifetime anxiety and affective disorders (r = 0.41), and the number of current drug dependence diagnoses and the number of current comorbid diagnoses (r = 0.32). After controlling for other variables, the only significant independent predictor of the number of lifetime and current dependence diagnoses was the number of comorbid diagnoses.

Heroin-related deaths in New South Wales, Australia, 1992-1996

The coronial files of all heroin-related fatalities that occurred in New South Wales (NSW) over the period 1992-1996 were inspected. There were 953 heroin-related fatalities in NSW over the study period. There was a substantial, statistically significant increase in heroin-related fatalities over the study period, from 152 deaths in 1992 to 226 during 1996. The mean age of cases was 31.0 years, 85% were male, and 85% were classified as dependent on heroin at the time of death. There was a significant increase in the age of cases over the study period and the proportion of cases that were employed. Fatalities predominantly occurred in home settings (61%). No intervention occurred in 79% of cases. Fifty deaths (5%) occurred in the month following release from prison, 16 of which occurred the first 24 hours after release. Morphine concentrations rose from 0.24 mg/l in 1992 to 0.38 mg/l in 1996. Seventy six percent of cases involved heroin in combination with other drugs: alcohol (46%), benzodiazepines (27%), antidepressants (7%) and cocaine (7%). In only 24% of cases was morphine the sole drug detected. Males were significantly more likely to have alcohol detected at autopsy (49 vs. 24%), while females were more likely to have benzodiazepines detected (41 vs. 17%). The median blood morphine concentration among cases in which alcohol was detected was significantly lower than other cases (0.27 vs. 0.39 mg/l). It is concluded that heroin-related deaths continued to rise throughout the study period, and that deaths were predominantly among older, untreated males. Despite the rise in blood morphine concentrations, polydrug use remained the predominant toxicological pattern.

Anxiety and working memory capacity

Abstract Two experiments were conducted to measure the comparative working memory capacities of highly anxious and low anxiety subjects. Experiment 1 employed a traditional digit span measure of capacity requiring storage only. The measure utilised in Experiment 2 required subjects to both process and store information. Highly anxious subjects exhibited significantly smaller measures of capacity in relation to the low anxiety groups in both experiments. It is concluded that high levels of anxiety reduces both the storage and processing capacity of working memory.

GHB use among Australians: characteristics, use patterns and associated harm

The aim of this study was to examine the characteristics of gamma-hydroxybutyrate (GHB) users, their GHB and other drug use patterns, and the harms associated with GHB use. Seventy-six GHB users were recruited and administered a structured interview on GHB use and related harms. GHB users appeared to be a stable, highly educated and well-functioning group. They had had extensive experience with a range of drugs, and GHB was typically used in conjunction with other drugs. Despite the fact that most GHB users had not had a long or extensive experience with GHB use, the proportion reporting significant negative side effects when using GHB was high (99% reported at least one), and the mean number of side effects ever experienced was 6.5. Notably, half (52%) reported becoming unconscious, 53% reported vomiting, 58% reported profuse sweating, and 8% reported having a fit or seizure. The high rate of problems reported by a group with limited use of this drug suggests that in a context of polydrug use, GHB use is associated with significant risks to users.