Biomedical subjects
Wayne Hall
Publications and source records attributed to Wayne Hall.
The "lessons" of the Australian "heroin shortage".
Heroin use causes considerable harm to individual users including dependence, fatal and nonfatal overdose, mental health problems, and blood borne virus transmission. It also adversely affects the community through drug dealing, property crime and reduced public amenity. During the mid to late 1990s in Australia the prevalence of heroin use increased as reflected in steeply rising overdose deaths. In January 2001, there were reports of an unpredicted and unprecedented reduction in heroin supply with an abrupt onset in all Australian jurisdictions. The shortage was most marked in New South Wales, the State with the largest heroin market, which saw increases in price, dramatic decreases in purity at the street level, and reductions in the ease with which injecting drug users reported being able to obtain the drug. The abrupt onset of the shortage and a subsequent dramatic reduction in overdose deaths prompted national debate about the causes of the shortage and later international debate about the policy significance of what has come to be called the "Australian heroin shortage". In this paper we summarise insights from four years' research into the causes, consequences and policy implications of the "heroin shortage".
Using intervention time series analyses to assess the effects of imperfectly identifiable natural events: a general method and example.
BACKGROUND: Intervention time series analysis (ITSA) is an important method for analysing the effect of sudden events on time series data. ITSA methods are quasi-experimental in nature and the validity of modelling with these methods depends upon assumptions about the timing of the intervention and the response of the process to it. METHOD: This paper describes how to apply ITSA to analyse the impact of unplanned events on time series when the timing of the event is not accurately known, and so the problems of ITSA methods are magnified by uncertainty in the point of onset of the unplanned intervention. RESULTS: The methods are illustrated using the example of the Australian Heroin Shortage of 2001, which provided an opportunity to study the health and social consequences of an abrupt change in heroin availability in an environment of widespread harm reduction measures. CONCLUSION: Application of these methods enables valuable insights about the consequences of unplanned and poorly identified interventions while minimising the risk of spurious results.
The mental health risks of adolescent cannabis use.
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Is cannabis use psychotogenic?
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Delivering on the promise of human stem-cell research. What are the real barriers?
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Documenting the heroin shortage in New South Wales.
Australian heroin markets have recently undergone dramatic change, sparking debate about the nature of such markets. This study aimed to determine the onset, peak and decline of the heroin shortage in New South Wales (NSW), using the most appropriate available methods to detect market level changes. The parameters of the heroin shortage were determined by reviewing: reports of heroin users about availability and price (derived from the existing literature and the Illicit Drug Reporting System); qualitative interviews with injecting drug users, and health and law enforcement professionals working in the illicit drug field; and examining data on heroin seizures over the past decade. There was a marked reduction in heroin supply in NSW in early 2001. An increase in the price of heroin occurred in 2001, whereas it had decreased steadily since 1996. A reduction in purity also occurred, as reported by drug users and heroin seizures. The peak period of the shortage appears to have been January to April 2001. The market appears to have stabilised since that time, although it has not returned to pre-2001 levels: heroin prices have decreased in NSW for street grams, but not to former levels, and the price of 'caps' (street deals) remain elevated. Heroin purity in NSW has remained low, with perhaps a 10% increase above the lowest recorded levels. These data support the notion that the heroin market in NSW underwent significant changes, which appear to have involved a lasting shift in the nature of the market.
Changes in the initiation of heroin use after a reduction in heroin supply.
Increasing heroin use in Australia over the past 30 years has been associated with a decline in the age of initiation to heroin use. The 2001 Australian heroin shortage was used to assess the effects of a reduction in heroin supply on age of initiation into heroin injecting. Data collected from regular injecting drug users (IDU) over the period 1996 - 2004 as part of the Australian Illicit Drug Reporting System were examined for changes in self-reported age of first heroin use after the onset of the heroin shortage. Estimates were also made of the number of young people who may not have commenced injecting heroin during the heroin shortage. The proportion of IDU interviewed in the IDRS who were aged <or=24 years decreased from 46% in 1996 to 12% in 2004, with the most marked drop in 2001, the year in which there was an abrupt and marked reduction in heroin availability. Of those who reported first injecting between 1993 and 2000, similar proportions reported heroin and amphetamine as the first drug injected. After 2000, methamphetamine was the drug most often reported as being the first injected. Estimates suggested that between 2745 and 10,560 young people may not have begun to inject heroin in 2001 as a result of reduced heroin supply. If around one in four of these young users had progressed to regular or dependent heroin use, then there may have been a reduction of between 700 and 2500 dependent heroin users. There was an increase in amphetamine injecting but it is unclear to what extent any reduction in heroin injecting has been offset by increased amphetamine injecting. Reduced heroin availability probably resulted in a reduction in the number of new heroin injectors in Australia. Efforts need to be made to reduce the chances that young people who have initiated methamphetamine injecting do not move to heroin injecting when the heroin supply returns.
Stereotactic neurosurgical treatment of addiction: minimizing the chances of another 'great and desperate cure'.
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Dissecting the causal anatomy of the link between cannabis and other illicit drugs.
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Ensuring that addiction science is deserving of public trust.
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Avoiding potential misuses of addiction brain science.
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Canadian heroin supply and the Australian 'heroin shortage'.
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The regulatory challenges in engineering a safer tipple.
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Is cannabis use a contributory cause of psychosis?
OBJECTIVE: To assess whether cannabis use in adolescence and young adulthood is a contributory cause of schizophreniform psychosis in that it may precipitate psychosis in vulnerable individuals. METHOD: We reviewed longitudinal studies of adolescents and young adults that examined the relations between self-reported cannabis use and the risk of diagnosis with a psychosis or of reporting psychotic symptoms. We also reviewed studies that controlled for potential confounders, such as other forms of drug use and personal characteristics that predict an increased risk of psychosis. We assessed evidence for the biological plausibility of a contributory causal relation. RESULTS: Evidence from 6 longitudinal studies in 5 countries shows that regular cannabis use predicts an increased risk of a schizophrenia diagnosis or of reporting symptoms of psychosis. These relations persisted after controlling for confounding variables, such as personal characteristics and other drug use. The relation did not seem to be a result of cannabis use to self-medicate symptoms of psychosis. A contributory causal relation is biologically plausible because psychotic disorders involve disturbances in the dopamine neurotransmitter systems with which the cannabinoid system interacts, as demonstrated by animal studies and one human provocation study. CONCLUSION: It is most plausible that cannabis use precipitates schizophrenia in individuals who are vulnerable because of a personal or family history of schizophrenia.
What are the policy implications of the evidence on cannabis and psychosis?
OBJECTIVE: To explore the implications for mental health services, for health education about the risks of cannabis use, and for public policy toward cannabis use of observational evidence that cannabis use is a contributory cause of psychosis. METHOD: Using comparative analyses of similar evidence for the harmful effects of alcohol, tobacco, and amphetamine use, we considered the relation between observational evidence and action on cannabis. We examined arguments on the grounds of public health prudence for discouraging cannabis use by young individuals. With the assumption that the relation may be causal, we considered recommendations for policy in mental health services, health education, and public policy toward cannabis. RESULTS: The observational evidence and biological plausibility of the hypothesis that cannabis is a contributory cause of psychosis is at least as strong as evidence for causal relations between heavy alcohol and amphetamine use and psychosis. On public health grounds, there is a good case for discouraging cannabis use among adolescents and young adults. It remains uncertain how best to discourage use and at whom campaigns to reduce cannabis use should be targeted. CONCLUSIONS: We should discourage young adults seeking treatment in mental health services from using cannabis and inform them of the probable mental health risks of cannabis use, especially of early and frequent use. We must exercise caution in liberalizing cannabis laws in ways that may increase young individuals' access to cannabis, decrease their age of first use, or increase their frequency of cannabis use. We should consider the feasibility of reducing the availability of high-potency cannabis products.
British drinking: a suitable case for treatment?
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Age differentials in the impacts of reduced heroin: effects of a "heroin shortage" in NSW, Australia.
BACKGROUND: This paper uses a unique event, the Australian heroin shortage, to see whether an abrupt, substantial and sustained change in heroin supply had different effects on harms related to heroin use among younger and older heroin users. METHOD: Indicator data were examined by age group on the number of persons entering treatment for heroin and amphetamine dependence, arrests for heroin use/possession and number of drug related deaths in NSW, Australia. Data were analysed using times series analysis. RESULTS: There was a 41% reduction in the number of new registrations for opioid pharmacotherapy per month among 25-34 year olds, and a 26% reduction among 15-24 year olds, but no apparent changes among older age groups. Similarly, reductions in the number of non-pharmacological heroin treatment episodes were most pronounced among younger age groups. There was a 49% reduction in the number of heroin possession/use offences among those aged 15-24 years, compared to declines of 31-40% among older age groups. Declines in heroin related deaths were greatest among 15-24 year olds (65% reduction). There was no change in other drug related deaths in any age group. CONCLUSIONS: A reduction in heroin supply was followed by greater reductions in heroin related harms among younger than older people, across a number of outcome domains.