Biomedical subjects

M Lynskey

Publications and source records attributed to M Lynskey.

At least 19 recordsLinked to original sources

PubMed2002

The genetics of tobacco use: methods, findings and policy implications.

Research on the genetics of smoking has increased our understanding of nicotine dependence, and it is likely to illuminate the mechanisms by which cigarette smoking adversely effects the health of smokers. Given recent advances in molecular biology, including the completion of the draft sequence of the human genome, interest has now turned to identifying gene markers that predict a heightened risk of using tobacco and developing nicotine dependence

Adoption↗

PubMed2001

The relationship between cannabis use and other substance use in the general population.

This study examined if (1) there is an association in the general population between cannabis use, DSM-IV abuse and dependence, and other substance use and DSM-IV substance abuse/dependence; (2) if so, is it explained by demographic characteristics or levels of neuroticism? It used data from the Australian National Survey of Mental Health and Well-Being (NSMHWB), a stratified, multistage probability sample of 10,641 adults, representative of the general population. DSM-IV diagnoses of substance abuse and dependence were derived using the Composite International Diagnostic Interview (CIDI). There was a strong bivariate association between involvement with cannabis use in the past 12 months and other substance use, abuse and dependence. In particular, cannabis abuse and dependence were highly associated with increased risks of other substance dependence. These associations remained after including other variables in multiple regression. Cannabis use without disorder was strongly related to other drug use, an association that was not explained by other variables considered here. The high likelihood of other substance use and substance use disorders needs to be considered among persons seeking treatment for cannabis use problems.

Adolescent↗

PubMed2001

The relationship between cannabis use, depression and anxiety among Australian adults: findings from the National Survey of Mental Health and Well-Being.

BACKGROUND: This study aimed to examine the patterns of association between cannabis use, and anxiety and affective disorders, in the general population. METHOD: Data from the Australian National Survey of Mental Health and Well-Being, a representative survey of Australians aged 18 years and over, were analysed to address the following questions: (1) is there an association between cannabis use, DSM-IV abuse and dependence, and DSM-IV affective and anxiety disorders; (2) if so, is it explained by: demographic characteristics, levels of neuroticism, or other drug use; and (3) does the presence of a comorbid affective or anxiety disorder affect the likelihood of treatment seeking among cannabis users? RESULTS: There was a moderate univariate association between involvement with cannabis use in the past 12 months and the prevalence of affective and anxiety disorders. Among those with DSM-IV cannabis dependence, 14% met criteria for an affective disorder, compared to 6% of non-users; while 17% met criteria for an anxiety disorder, compared to 5% of non-users. These associations did not remain significant after including demographics, neuroticism and other drug use in multiple regressions. CONCLUSIONS: Cannabis use did not appear to be directly related to depression or anxiety when account was taken of other drug use. However, the association between heavier involvement with cannabis use and affective and anxiety disorders has implications for the treatment of persons with problematic cannabis use.

Adolescent↗

PubMed2001

Adverse outcomes of alcohol use in adolescents.

AIMS: To compare the occurrence of behaviours occurring under the influence of alcohol in 16-17-year-olds and determine associated risk factors for the different behaviours. DESIGN/SETTING: Cross-sectional survey administered by laptop computers in secondary schools across the state of Victoria, Australia. MEASUREMENT/FINDINGS: The participation rate was 79%. Seventy per cent of participants drank alcohol; 17% of drinkers reported alcohol-related violence (accidents or injuries) and 15% reported problems relating to sex under the influence of alcohol (having sex and later regretting it or having had unsafe sex) in the previous 12 months. Males were more likely to report alcohol-related violence (20% compared to 14% females). Almost one in 10 young people reported having sex while under the influence of alcohol and later regretting it and 10% reported having had unsafe sex. There were no significant gender differences in the reporting rates of alcohol-related sexual risk taking (prop. cum. OR 1.1, 95% CI 0.68-1.9). For alcohol-related injuries, strong independent associations were found with dose of alcohol consumed (prop. cum. OR 2.3, 95% CI 1.3-4.0), frequency of alcohol consumption (prop. cum. OR 2.7, 95% CI 0.94-7.5), antisocial behaviour (prop. cum. OR 2.4, 95% CI 1.4-4.1) and peer drinking (prop. cum. OR 3.3, 95% CI 1.4-8.1). For alcohol-related sexual risk-taking, psychiatric morbidity (prop. cum. OR 4.1, 95% CI 1.9-9.0) and high frequency of alcohol consumption (prop. cum. OR 2.0, 95% CI 0.87-4.6) had strong independent associations. CONCLUSIONS: Physical injury and high-risk sexual behaviour under the influence of alcohol are common in teenagers. Alcohol-related physical injury appears closely related to patterns of alcohol consumption whereas alcohol-related sexual risk-taking is most closely associated with symptoms of depression and anxiety.

Adolescent↗

PubMed2001

Alcohol, cannabis and tobacco use among Australians: a comparison of their associations with other drug use and use disorders, affective and anxiety disorders, and psychosis.

AIM: To compare relationships between alcohol, cannabis and tobacco and indicators of mental health problems in the general population. METHOD: A survey of a nationally representative sample of 10 641 Australian adults (the National Survey of Mental Health and Well-Being (NSMHWB)) provided data on alcohol, cannabis and tobacco use and mental health (DSM-IV anxiety disorders, affective disorders, other substance use disorders and screening positively for psychosis). FINDINGS: Alcohol showed a "J-shaped" relationship with DSM-IV affective and anxiety disorders: alcohol users had lower rates of these problems than non-users of alcohol, while those meeting criteria for alcohol dependence had the highest rates. Tobacco and cannabis use were both associated with increased rates of all mental health problems examined. However, after controlling for demographics, neuroticism and other drug use, cannabis was not associated with anxiety or affective disorders. Alcohol dependence and tobacco use remained associated with both of these indicators of mental health. All three types of drug use were associated with higher rates of other substance use problems, with cannabis having the strongest association. CONCLUSIONS: The use of alcohol, tobacco and cannabis are associated with different patterns of co-morbidity in the general population.

Adolescent↗

PubMed2001

Back-projection estimates of the number of dependent heroin users in Australia.

AIMS: To plan an appropriate response to heroin use in Australia, good estimates are needed of the numbers of dependent heroin users, the group who are most in need of treatment, most at risk of fatal opioid overdose and most at risk of contracting and transmitting blood-borne viruses. METHODS: Back-projection methods were used to estimate the numbers of people starting dependent heroin injecting in Australia between 1960 and 1997. Separate analyses were based on national opioid overdose deaths and numbers of new entrants to methadone treatment in New South Wales (NSW). Estimates of the rates at which dependent heroin users cease heroin use, commence methadone treatment or die from opioid overdoses were estimated from external data sources. RESULTS: Back-projection estimates derived from opioid overdose deaths indicated that there were 104 000 (lower limit of 72 000 and upper limit of 157 000) people who were heroin dependent in Australia between 1960 and 1997. Of these it was estimated that 67 000 (39 000-120 000) were still heroin dependent at the end of 1997. Back-projection estimates based on numbers of new entrants to methadone treatment in NSW indicated that there were 108 000 (82 000-141 000) heroin-dependent people in Australia between 1960 and 1997, of whom 71 000 (47 000-109 000) were estimated to be heroin dependent at the end of 1997. Both analyses indicated that the number of heroin-dependent people in Australia has increased substantially from the early 1970s onwards. CONCLUSIONS: Back-projection estimates based on analyses of treatment entries and opioid overdose deaths provide an additional method for estimating the numbers of heroin-dependent people in the population. The addition of these methods to existing methods, using different data sources and statistical methods, should improve consensus estimates of the numbers of heroin-dependent people.

Adolescent↗

PubMed2001

Heroin overdose: causes and consequences.

Over the past decade fatal opioid overdose has emerged as a major public health issue internationally. This paper examines the risk factors for overdose from a biomedical perspective. While significant risk factors for opioid overdose fatality are well recognized, the mechanism of fatal overdose remains unclear. Losses of tolerance and concomitant use of alcohol and other CNS depressants clearly play a major role in fatality; however, such risk factors do not account for the strong age and gender patterns observed consistently among victims of overdose. There is evidence that systemic disease may be more prevalent in users at greatest risk of overdose. We hypothesize that pulmonary and hepatic dysfunction resulting from such disease may increase susceptibility to both fatal and non-fatal overdose. Sequelae of non-fatal overdose are recognized in the clinical literature but few epidemiological data exist describing the burden of morbidity arising from such sequelae. The potential for overdose to cause persisting morbidity is reviewed.

Adolescent↗

PubMed2001

Challenges and approaches to estimating mortality attributable to the use of selected illicit drugs.

A number of unique challenges are faced when attempting to estimate mortality attributable to illicit drugs. The hidden nature of illicit drug use creates difficulties in quantifying the prevalence of such use; identifying adverse health effects associated with exposure, and calculating the risk of these effects. The use of cohort studies of drug users allows the identification of causes of mortality associated with drug use and the determination of the risk of these causes. This risk estimate can then be used in conjunction with estimates of the prevalence of drug use to extrapolate the burden of mortality. We identify a number of such studies and present some solutions to the major challenges faced when attempting to estimate the global burden of mortality attributable to illicit drug use.

Cohort Studies↗

PubMed2000

Trends in opiate-related deaths in the United Kingdom and Australia, 1985-1995.

This paper compares data on rates of opiate overdose mortality in the UK and Australia between 1985 and 1995. Data on rates of ICD 9-coded overdose mortality were obtained from the Office of National Statistics in the UK and from the Australian Bureau of Statistics mortality register. The proportion of all deaths attributed to opioid overdose increased in both countries between 1985 and 1995. The proportion of all deaths attributed to opioid overdose was substantially higher in Australia than in the UK, but methadone appeared to contribute to more opioid overdose deaths in the UK (50%) than in Australia (18%). Given deficiencies in the available data, the reasons for these differences between the two countries are uncertain but a plausible hypothesis is that the greater availability and ease of access to methadone maintenance in the UK contributes to both the lower rate of opioid overdose mortality and the greater apparent contribution that methadone makes to opioid overdose deaths in that country.

Adolescent↗

PubMed2000

The effects of adolescent cannabis use on educational attainment: a review.

This paper reviews research examining the link between cannabis use and educational attainment among youth. Cross-sectional studies have revealed significant associations between cannabis use and a range of measures of educational performance including lower grade point average, less satisfaction with school, negative attitudes to school, increased rates of school absenteeism and poor school performance. However, results of cross-sectional studies cannot be used to determine whether cannabis use causes poor educational performance, poor educational performance is a cause of cannabis use or whether both outcomes are a reflection of common risk factors. Nonetheless, a number of prospective longitudinal studies have indicated that early cannabis use may significantly increase risks of subsequent poor school performance and, in particular, early school leaving. This association has remained after control for a wide range of prospectively assessed covariates. Possible mechanisms underlying an association between early cannabis use and educational attainment include the possibility that cannabis use induces an 'amotivational syndrome' or that cannabis use causes cognitive impairment. However, there appears to be relatively little empirical support for these hypotheses. It is proposed that the link between early cannabis use and educational attainment arises because of the social context within which cannabis is used. In particular, early cannabis use appears to be associated with the adoption of an anti-conventional lifestyle characterized by affiliations with delinquent and substance using peers, and the precocious adoption of adult roles including early school leaving, leaving the parental home and early parenthood.

Adolescent↗

PubMed2000

Initiation and progression of cannabis use in a population-based Australian adolescent longitudinal study.

AIMS: To examine predictors of cannabis use initiation, continuity and progression to daily use in adolescents. DESIGN: Population-based cohort study over 3 years with 6 waves of data collection. PARTICIPANTS: 2032 students, initially aged 14-15 years, from 44 secondary schools in the state of Victoria, Australia. MEASUREMENTS: Self-report cannabis use was categorized on four levels (none, any, weekly, daily) and summarized as mid-school (waves 2/3) and late-school (waves 4/5/6) use. Background, school environment, mid-school peer use and individual characteristics were assessed. FINDINGS: Peer cannabis use, daily smoking, alcohol use, antisocial behaviour and high rates of school-level cannabis use were associated with mid-school cannabis use and independently predicted late-school uptake. Cannabis use persisted into late-school use in 80% of all mid-school users. Persisting cannabis use from mid- to late-school was more likely in regular users (odds ratio (OR) 3.4), cigarette smokers (OR any smoking: 2.0, daily smoking: 3.3) and those reporting peer use (OR 2.1). Mid-school peer use independently predicted incident late-school daily use in males (OR 6.5) while high-dose alcohol use (OR 6.1) and antisocial behaviour (OR 6.6) predicted incident late-school daily use in females. CONCLUSIONS: Most cannabis use remained occasional during adolescence but escalation to potentially harmful daily use in the late-school period occurred in 12% of early users. Transition was more likely in males, for whom availability and peer use were determinants. In contrast, females with multiple extreme behaviours were more likely to become daily users. Cigarette smoking was an important predictor of both initiation and persisting cannabis use.

Adolescent↗

PubMed2000

Alcohol- and drug-use disorders in Australia: implications of the National Survey of Mental Health and Wellbeing.

OBJECTIVE: This study reports the prevalence and correlates of ICD-10 alcohol- and drug-use disorders in the National Survey of Mental Health and Wellbeing (NSMHWB) and discusses their implications for treatment. METHOD: The NSMHWB was a nationally representative household survey of 10641 Australian adults that assessed participants for symptoms of the most prevalent ICD-10 and DSM-IV mental disorders, including alcohol- and drug-use disorders. RESULTS: In the past 12 months 6.5% of Australian adults met criteria for an ICD-10 alcohol-use disorder and 2.2% had another ICD-10 drug-use disorder. Men were at higher risk than women of developing alcohol- and drug-use disorders and the prevalence of both disorders decreased with increasing age. There were high rates of comorbidity between alcohol- and other drug-use disorders and mental disorders and low rates of treatment seeking. CONCLUSIONS: Alcohol-use disorders are a major mental health and public health issue in Australia. Drug-use disorders are less common than alcohol-use disorders, but still affect a substantial minority of Australian adults. Treatment seeking among persons with alcohol- and other drug-use disorders is low. A range of public health strategies (including improved specialist treatment services) are needed to reduce the prevalence of these disorders.

Adolescent↗

PubMed2000

Cohort trends in youth suicide in Australia 1964-1997.

OBJECTIVE: This paper examines trends in the rate of suicide among young Australians aged 15-24 years from 1964 to 1997 and presents an age-period-cohort analysis of these trends. METHOD: Study design consisted of an age-period-cohort analysis of suicide mortality in Australian youth aged between 15 and 24 for the years 1964-1997 inclusive. Data sources were Australian Bureau of Statistics data on: numbers of deaths due to suicide by gender and age at death; and population at risk in each of eight birth cohorts (1940-1944, 1945-1949, 1950-1954, 1955-1959, 1960-1964, 1965-1969, 1970-1974, and 1975-1979). Main outcome measures were population rates of deaths among males and females in each birth cohort attributed to suicide in each year 1964-1997. RESULTS: The rate of suicide deaths among Australian males aged 15-24 years increased from 8.7 per 100,000 in 1964 to 30.9 per 100,000 in 1997, with the rate among females changing little over the period, from 5.2 per 100,000 in 1964 to 7.1 per 100,000 in 1997. While the rate of deaths attributed to suicide increased over the birth cohorts, analyses revealed that these increases were largely due to period effects, with suicide twice as likely among those aged 15-24 years in 1985-1997 than between 1964 and 1969. CONCLUSIONS: The rate of youth suicide in Australia has increased since 1964, particularly among males. This increase can largely be attributed to period effects rather than to a cohort effect and has been paralleled by an increased rate of youth suicides internationally and by an increase in other psychosocial problems including psychiatric illness, criminal offending and substance use disorders.

Adolescent↗

PubMed2000

Cannabis use among Australian adolescents: findings of the 1998 National Drug Strategy Household Survey.

OBJECTIVE: To describe the prevalence, context and recent trends in cannabis use among Australian adolescents. METHOD: Data was collected from 1,581 adolescents aged 14-19 years as part of the 1998 National Drug Strategy Household Survey, and comparisons were made with data from 350 adolescents who participated in the 1995 survey. RESULTS: Among 14-19 year olds, 47.8% have had the opportunity to use cannabis in the past year and 45.2% have used cannabis at least once in their lifetime. Substantial increases have occurred since 1995 in the prevalence of use among young females. While most cannabis use was fairly infrequent, a minority of 14-19 year olds (9.4%) used cannabis at least weekly. Cannabis use was associated with regular tobacco and alcohol use, and other illicit drug use. Regular cannabis users had lower levels of health on the general health and vitality dimensions of the SF-36. IMPLICATIONS: These results show that cannabis availability and use is common among Australian adolescents, and confirm that there has been an increase in use between 1995 and 1998, although only among young females. Future research is required to understand why this recent increase has occurred, and trends in cannabis uptake and use patterns among this group should be carefully monitored. Interventions may need to be developed and made available to the group of young people who are using cannabis heavily.

Adolescent↗

PubMed2000

Cohort trends in the age of initiation of drug use in Australia.

AIM: To examine birth cohort trends in the prevalence of use and the age of initiation of use of: alcohol, tobacco, cannabis, amphetamines, LSD, and heroin. METHOD: Data were taken from the 1998 National Drug Strategy Household Survey, a survey of a representative sample of Australians aged 14 years and over. Nine five-year cohorts were examined among persons born between 1940 and 1984. The weighted prevalence of use by ages 15 years, 21 years, and lifetime use, was estimated, as was the average age of first use among users. The significance of trends was tested using logistic regression (for lifetime use, use by 15 and 21 years) and linear regression (for age of first use). RESULTS: Lifetime prevalence of alcohol and tobacco use was similar among all birth cohorts. The prevalence of illicit drug use--cannabis, amphetamines, LSD and heroin--increased with successive birth cohorts and more recent birth cohorts reported using licit and illicit drugs at a younger age. CONCLUSIONS: More recent cohorts are more likely to use illicit drugs at some point in their lives. Greater numbers of persons from more recent birth cohorts may be at risk of developing substance-related problems.

Adolescent↗

PubMed1999

Prevalence of illicit drug use among youth: results from the Australian School Students' Alcohol and Drugs Survey.

OBJECTIVE: To estimate the prevalence of illicit drug use among Australian secondary school students. METHOD: Data was collected as part of the Australian School Student's Alcohol and Drugs Survey, a national survey of 29,447 secondary school students. RESULTS: Of all students aged 12-17 years, 39.9% (44.1% of males and 35.9% of females) reported having used at least one illicit drug in their lifetime. Cannabis was the most widely used illicit drug with 36.4% of all students reporting having used cannabis. Substantially fewer students reported using other drugs: hallucinogens (8.6%), amphetamines (6.1%), cocaine (3.6%), ecstasy (3.6%), opiates (3.7%) and steroids (1.8%). There were clear gender and age differences in the prevalence of illicit drug use: more males than females reported illicit drug use and the lifetime prevalence of illicit drug use increased with age. Most of those who reported illicit drug use had used drugs on relatively few occasions although there was a small minority of the sample who reported more frequent use. Finally, there were strong association between regular cannabis use and the use of other illicit drugs in the past year, and moderate associations between illicit drug use and the extent of both tobacco and alcohol use. CONCLUSIONS: The findings of this, the first national survey of illicit drug use among Australian school students, indicate a high prevalence of illicit drug use. Comparisons with previous regionally based surveys suggest there may have been a recent increase in the prevalence of cannabis use and highlight the need for further monitoring of and prevention efforts aimed at reducing illicit drug use among students.

Adolescent↗

PubMed1999

The 12-month prevalence of substance use and ICD-10 substance use disorders in Australian adults: findings from the National Survey of Mental Health and Well-Being.

AIMS: To present the prevalence of substance use and ICD-10 substance use disorders in the adult Australian population using data from the National Survey of Mental Health and Well-Being (NSMHWB). DESIGN: A cross-sectional survey assessing substance use and ICD substance use disorders (harmful use and dependence). SETTING AND PARTICIPANTS: A household survey of a nationally representative sample of 10,641 Australian adults (aged 18 years or older). MEASUREMENTS: Trained survey interviewers administered a structured interview based on the Composite International Diagnostic Interview (CIDI). FINDINGS: In the past 12 months 6.5% of the sample had an ICD-10 alcohol use disorder (95% CI: 6.2, 6.9), and 2.2% had another drug use disorder (95% CI: 2.0, 2.4). More males than females had substance use disorders: 9.5% of males (95% CI: 8.5, 10.5) and 3.6% of females (95% CI: 3.2, 4.0) met criteria for an alcohol use disorder, and 3.2% of males (95% CI: 2.8, 3.6) and 1.3% of females (95% CI: 0.9, 1.7) met criteria for another drug use disorder within the past 12 months. The prevalence of substance use disorders decreased with increasing age: 10.5% of respondents aged 18-34 years met criteria for an alcohol use disorder and 4.8% met criteria for a drug use disorder. The rates of these disorders among those aged 55 years or older were 1.8% and 0.1%, respectively. Substance use disorders were more prevalent among the unemployed, those who had never married and those who were Australian-born. CONCLUSIONS: The prevalence of substance use disorders in the Australian population is comparable to that in other English-speaking countries.

Adult↗

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↗