Joanne Ross

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.

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.

Hepatitis C-related discrimination among heroin users in Sydney: drug user or hepatitis C discrimination?

The hepatitis C virus (HCV) is a common infection among injecting drug users. There are currently few available data on the extent (or prevalence) of HCV-related discrimination. This study examined perceived discrimination among a sample of heroin users and sought to determine whether the discrimination was attributed to their drug user or HCV status. Heroin users were recruited through needle and syringe programmes and methadone clinics in Sydney and were asked about discrimination in the preceding 12 months. Four hundred and one heroin users were recruited, of whom 59% reported being HCV-positive. Discrimination was reported by 22% of the 237 IDUs who reported being HCV-positive, with 17% reporting that the discrimination occurred in the preceding 12 months. Sixty-seven incidents were reported, of which half were perceived to be due to their drug user status, 15% of these incidents were due to HCV status and 25% due to a combination of both. Twenty-five incidents occurred in a health-care setting, of which 13 resulted in the service being withheld. HCV is a serious public health concern, and if IDU are to be encouraged into drug treatment it is essential that service providers are perceived to be non-discriminatory. In managing IDU patients, health care workers need to be cognizant of the impact that their attitude has on treatment outcome.

Physical injecting sites among injecting drug users in Sydney, Australia

A sample of 200 injecting drug users were interviewed about their bodily injection sites. The mean number of injection sites ever used by subjects was 3.1, with a mean of 2.0 sites used in the previous 6 months. Sixteen percent of subjects had injected in five or more sites. Almost all (99%) had injected in the cubital fossa (crook of the arm). The next most popular site was the forearm (71%). Other sites included the hand (53%), foot (19%), leg (18%), neck (10%) and groin (6%). There was a clear progression in sites used, from the cubital fossa at initial injection to the use of sites such as the groin after 10 years of injecting. Females had used significantly more injection sites than males and reported more injection-related problems. The use of more injection sites was independently associated with a greater number of injection-related problems and a greater number of drug classes ever injected.

Non-fatal heroin overdose, treatment exposure and client characteristics: Findings from the Australian treatment outcome study (ATOS)

The relationship between treatment exposure, drug use, psychosocial variables and non-fatal heroin overdose was examined among a cohort of 495 heroin users, re-interviewed at 12 months. The 12-month overdose rate declined from 24% to 12%, and the proportion administered naloxone declined from 15% to 7%. There were significant reductions in overdose among those who entered maintenance therapies (22% to 4%) and residential rehabilitation (33% vs. 19%) at baseline, but not among those who entered detoxification or were not entering treatment. The total number of treatment days received over the follow-up period was associated independently with a reduced risk of overdose. Each extra treatment day was associated with a 1% reduction in risk of overdose over the follow-up period. By contrast, more treatment episodes were associated with an increased risk of overdose (OR 1.62). Other independent predictors of overdose over follow-up were more extensive polydrug use (OR 1.40), and having overdosed in the year preceding the study (OR 7.87).

Prevalence and correlates of the injection of methadone syrup in Sydney, Australia

A sample of 312 heroin users was interviewed on their injection of methadone syrup. Methadone injecting was widespread, with 52% of subjects having injected methadone syrup, 29% in the preceding six months. Males and females were equally likely to report methadone injecting. Forty per cent of current methadone injectors reported weekly or more frequent methadone injecting over the preceding six months. A history of methadone injecting was associated with abscesses and infections in injection sites, having been diagnosed with a venous thrombosis and a history of heroin overdose. Current methadone injectors were in poorer general health, had more injection-related symptoms, higher levels of psychological distress, were more likely to have recently passed on used injecting equipment and to have recently committed criminal acts. Implications for the reduction in the prevalence of methadone injecting and associated harm are discussed.

Rates and correlates of mortality amongst heroin users: findings from the Australian Treatment Outcome Study (ATOS), 2001-2009.

The study aimed to determine mortality rates, standardised mortality ratios (SMRs), and correlates of mortality amongst the Australian Treatment Outcome Study (ATOS) cohort of 615 heroin users over the period 2001-2009. The cohort was followed for a total of 4820.1 person years. A total of 31 deaths (5% of the cohort) occurred across follow-up. The mean age at death was 34.5 years, and 58% were male. The most common cause of death was overdose (68%). The crude mortality rate was 6.43 per 1000 person years, with no gender difference, and the SMR was 4.56 (males=2.95, females=18.57). The only significant bivariate (hazard ratio=3.69) and multivariate (adjusted hazard ratio=3.03) correlate of mortality was a history of opioid overdose prior to baseline. Mortality rates were lower than those seen outside Australasia. Screening for overdose by those treating heroin users would be appropriate, and may contribute to reductions in overall mortality.

Comparative rates of violent crime among regular methamphetamine and opioid users: offending and victimization

AIMS To determine the comparative levels of violent offending and victimization among regular methamphetamine and heroin users. DESIGN Cross-sectional Setting Sydney, Australia. PARTICIPANTS A total of 400 regular methamphetamine (METH) and heroin (HER) users (118 methamphetamine users: METH; 161 regular heroin users: HER; 121 regular users of both: BOTH). FINDINGS Eighty-two per cent reported a life-time history of committing violent crime, 41% in the past 12 months. There were no group differences in life-time violence, but the METH group were significantly more likely than the HER group to have committed violence in the past 12 months (odds ratio 1.94). Nearly all (95%) reported that they had been a victim of violent crime, 46% in the preceding 12 months, with no group differences. Those who had committed a violent crime in the past 12 months were 13.23 times more likely to have been a victim in that period. The majority believed it unlikely that they would be a victim of (78%), or commit (87%), a violent crime in the next 12 months. CONCLUSIONS Regular methamphetamine use appears to be associated with an increased risk of violent offending, but not victimization, compared with heroin use.