Heavy cannabis use and depressive symptoms in three Aboriginal communities in Arnhem Land, Northern Territory

OBJECTIVE

To determine the extent to which depressive symptoms are associated with heavy cannabis use in an Aboriginal population in Arnhem Land, Northern Territory.

DESIGN, PARTICIPANTS AND SETTING

Cross-sectional study involving interviews with 106 Indigenous participants (57 males, 49 females) aged 13-42 years in three remote Aboriginal communities in Arnhem Land, NT, Australia.

MAIN OUTCOME MEASURES

Measures of depressive symptoms (a raw score of > or = 6 out of a possible 18 on a modified version of the Patient Health Questionnaire-9) and self-reported heavy cannabis use (six or more cones daily).

RESULTS

After adjusting for other substance use (tobacco, alcohol and lifetime petrol sniffing), age and sex, heavy cannabis users were four times more likely than the remainder of the sample to report moderate to severe depressive symptoms (odds ratio, 4.1; 95% CI, 1.3-13.4).

CONCLUSIONS

Given its high prevalence in Indigenous populations, the development of clinical and prevention strategies for cannabis misuse are warranted.

Parental smoking and smoking experimentation in childhood increase the risk of being a smoker 20 years later: the Childhood Determinants of Adult Health Study

AIMS

To examine the long-term effects of childhood smoking experimentation and exposure to parental smoking on adult smoking risk.

METHODS

Data were from a 20-year follow-up of 9-15-year-olds who completed questionnaires in the 1985 Australian Schools Health and Fitness Survey (n=6559). The relative risks (RR) of adult current smoking in 2004-05 for childhood exposure to smoking experimentation (never, a few puffs, <10 cigarettes, >10 cigarettes) and parental smoking (none, father, mother, both parents) in 1985, with adjustment for confounders, were estimated by log binomial modelling. Analyses were stratified by age (9-13 and 14-15 years) and sex.

FINDINGS

Participation at follow-up was 54% (n=3559). Childhood smoking experimentation increased the risk of being a current smoker particularly for 14-15-year-old experimenters of more than 10 cigarettes [males, RR 2.72, 95% confidence interval (CI) 1.74-4.25; females, RR 6.39, 95% CI 2.85-14.33]. Parental smoking was associated with adult current smoking risk, particularly for 9-13-year-olds with two smoking parents (males, RR 1.53, 95% CI 1.19-1.96; females, RR 1.99, 95% CI 1.52-2.61) and older males with smoking mothers (RR 1.82, 95% CI 1.22-2.73). Parental smoking was not associated with childhood smoking experimentation.

CONCLUSIONS

These findings suggest that any childhood smoking experimentation increases the risk of being a smoker 20 years later. As exposure to parental smoking predicted current smoking, parents should be aware of the association between their own smoking behaviour and that of their children.

Prognosis of adolescent partial syndromes of eating disorder

BACKGROUND

Partial syndromes of eating disorder are common in adolescents but the health significance of these syndromes remains uncertain.

AIMS

To document the health and social adjustment in young adulthood of females assessed as having a partial syndrome of eating disorder in adolescence.

METHOD

A community sample of 1943 participants was tracked over 10 years in an eight-wave cohort study. A partial syndrome was defined as the fulfilment of at least two DSM-IV criteria for either anorexia or bulimia nervosa at one assessment or more between the ages of 15 years and 17 years.

RESULTS

Partial syndromes were found in 9.4% of 15- to 17-year-old female participants and 1.4% of males. There were few instances of progression of partial syndromes to fully fledged anorexia and bulimia nervosa. However, among those with partial syndromes depressive and anxiety symptoms were two to three times higher in young adulthood, substance misuse was common, and a majority of those with a partial syndrome of anorexia nervosa were still underweight in their mid-20s.

CONCLUSIONS

Given the level of subsequent psychopathology and social role impairment, there may be justification for initiating trials of preventive and early clinical intervention strategies for adolescent partial syndromes.

Are diagnostic orphans at risk of developing cannabis abuse or dependence? Four-year follow-up of young adult cannabis users not meeting diagnostic criteria

OBJECTIVE

To examine the characteristics of "diagnostic orphans" among cannabis users - those who report one or two symptoms of DSM-IV dependence but do not meet diagnostic criteria for DSM-IV abuse or dependence - 4 years post-assessment.

METHOD

Data were collected from a representative population cohort of young Australian adults. Those who reported that they had used cannabis at least weekly at some point within the past year were assessed for symptoms of DSM-IV cannabis abuse and dependence using the Composite International Diagnostic Interview at age 20-21 years. The entire sample was followed up 4 years later. At age 24-25 years, cannabis use and cannabis diagnostic category were examined according to diagnostic category at age 20-21 years.

RESULTS

Diagnostic orphans at age 20-21 years were more likely than non-problem cannabis users at that age to be using cannabis, and to meet criteria for cannabis abuse or dependence 4 years later. Those who had met criteria for cannabis abuse or dependence, however, appeared to be at greater risk relative to non-problematic users and diagnostic orphans of meeting criteria for cannabis abuse and dependence at follow-up.

CONCLUSIONS

Young adult diagnostic orphans for cannabis use appear to be at lower risk of meeting full (or partial) diagnostic criteria after a 4-year follow-up, compared to those who had met criteria for cannabis abuse or dependence. This suggests that there is prognostic diagnostic utility in the threshold for dependence symptoms among young adult cannabis users. Diagnostic orphans did appear to be at greater risk than non-problem users for developing dependent and daily cannabis use, however, suggesting that clinicians would do well to intervene with this group.

COMT Val158Met and 5HTTLPR functional loci interact to predict persistence of anxiety across adolescence: results from the Victorian Adolescent Health Cohort Study

We investigated whether a composite genetic factor, based on the combined actions of catechol-O-methyltransferase (COMT) (Val(158)Met) and serotonin transporter (5HTTLPR) (Long-Short) functional loci, has a greater capacity to predict persistence of anxiety across adolescence than either locus in isolation. Analyses were performed on DNA collected from 962 young Australians participating in an eight-wave longitudinal study of mental health and well-being (Victorian Adolescent Health Cohort Study). When the effects of each locus were examined separately, small dose-response reductions in the odds of reporting persisting generalized (free-floating) anxiety across adolescence were observed for the COMT Met(158) [odds ratio (OR) = 0.85, 95% confidence interval (CI) = 0.76-0.95, P = 0.004] and 5HTTLPR Short alleles (OR = 0.88, CI = 0.79-0.99, P = 0.033). There was no evidence for a dose-response interaction effect between loci. However, there was a double-recessive interaction effect in which the odds of reporting persisting generalized anxiety were more than twofold reduced (OR = 0.45, CI = 0.29-0.70, P < 0.001) among carriers homozygous for both the COMT Met(158) and the 5HTTLPR Short alleles (Met(158)Met + Short-Short) compared with the remaining cohort. The double-recessive effect remained after multivariate adjustment for a range of psychosocial predictors of anxiety. Exploratory stratified analyses suggested that genetic protection may be more pronounced under conditions of high stress (insecure attachments and sexual abuse), although strata differences did not reach statistical significance. By describing the interaction between genetic loci, it may be possible to describe composite genetic factors that have a more substantial impact on psychosocial development than individual loci alone, and in doing so, enhance understanding of the contribution of constitutional processes in mental health outcomes.

Who are the new amphetamine users? A 10-year prospective study of young Australians

AIMS

Despite good evidence of increased availability and use of amphetamines world-wide, relatively little is known about the epidemiology of young adult amphetamine use; relationships with social functioning, other drug use and mental health at this age; nor of the adolescent predictors of such use. We examined these issues using a representative cohort of young people followed-up in Victoria, Australia.

METHODS

A stratified, random sample of 1943 adolescents was recruited from secondary schools across Victoria at age 14-15 years. This cohort was interviewed on eight occasions until the age of 24-25 years (78% follow-up at that age). Cross-sectional and predictive associations were assessed using logistic regression.

RESULTS

At age 24 years, 12% of the sample had used amphetamines in the past year, with 1-2% using at least weekly. Young adult amphetamine use was predicted strongly by adolescent drug use and was associated robustly with other drug use and dependence in young adulthood. Associations were stronger for more frequent users. Among young adults who had not been using amphetamines at age 20 years, the strongest predictor of use at age 24 years was the use of other drugs, particularly cannabis, at 20 years. Psychological distress did not predict independently an increased likelihood of amphetamine use in this cohort.

CONCLUSION

Young people in Australia using amphetamine at age 24 years are highly likely to be significant polydrug users. The risks for both initiation of young adult amphetamine use, and maintenance of such use, pertain to the heavy use of other drugs. Interventions for heavy amphetamine users at this age are likely to require attention to multiple drug problems.

Variation in the gene coding for the M5 muscarinic receptor (CHRM5) influences cigarette dose but is not associated with dependence to drugs of addiction: evidence from a prospective population based cohort study of young adults

Background

The mesolimbic structures of the brain are important in the anticipation and perception of reward. Moreover, many drugs of addiction elicit their response in these structures. The M5 muscarinic receptor (M5R) is expressed in dopamine-containing neurones of the substantia nigra pars compacta and ventral tegmental area, and regulates the release of mesolimbic dopamine. Mice lacking M5R show a substantial reduction in both reward and withdrawal responses to morphine and cocaine. The CHRM5, the gene that codes for the M5R, is a strong biological candidate for a role in human addiction. We screened the coding and core promoter sequences of CHRM5 using denaturing high performance liquid chromatography to identify common polymorphisms. Additional polymorphisms within the coding and core promoter regions that were identified through dbSNP were validated in the test population. We investigated whether these polymorphisms influence substance dependence and dose in a cohort of 1947 young Australians.

Results

Analysis was performed on 815 participants of European ancestry who were interviewed at wave 8 of the cohort study and provided DNA. We observed a 26.8% increase in cigarette consumption in carriers of the rs7162140 T-allele, equating to 20.1 cigarettes per week (p=0.01). Carriers of the rs7162140 T-allele were also found to have nearly a 3-fold increased risk of developing cannabis dependence (OR=2.9 (95%CI 1.1-7.4); p=0.03).

Conclusion

Our data suggest that variation within the CHRM5 locus may play an important role in tobacco and cannabis but not alcohol addiction in European ancestry populations. This is the first study to show an association between CHRM5 and substance use in humans. These data support the further investigation of this gene as a risk factor in substance use and dependence.

Service responses for youth onset mental disorders

PURPOSE OF REVIEW

Many psychiatric disorders have their highest first-onset rates in adolescence and young adulthood. We summarize recent work indicating where interventions are most needed and effective. We also review the literature that examines the scope for reorienting mental health services to meet the needs of adolescents and young adults.

RECENT FINDINGS

The continuities between youth onset and later life disorders, as well as later social adjustment, have become clearer. Emotional disorders that persist or recur during the teens have the greatest effect on future mental health. To date, service systems, even in the developed world, cater poorly for youth with mental disorders. Intervention studies demonstrate the short-term benefits of intensive multidisciplinary intervention for early psychosis. There are few data concerning the benefit of early intervention for other disorders. Long-term benefits for early intervention for any condition are unknown. Youth streams of psychiatric care have developed for early-onset psychotic disorders.

SUMMARY

An increasing understanding of the high prevalence and longer-term effects of youth onset mental disorders has not yet been adequately matched by intervention research or the evaluation of different models of mental health service delivery.

A training agenda in adolescent medicine and health

The complexity of health issues facing young people, an appreciation that problems arising in adolescence may have long term implications for health, and greater confidence about the value of clinical intervention are key factors underpinning current efforts in Australia to build an education agenda for health professionals working with young people. This paper outlines a series of education initiatives in both undergraduate and postgraduate settings and discusses the growing support for more strategic and coherent approaches to education nationally. In particular, efforts to improve the capacity of health professionals to work with young people are described, together with the opportunity for more focused subspeciality training in Adolescent Medicine. Within our region and beyond, Australia is increasingly being turned to as a model of academic leadership in adolescent medicine, including professional education and training. In Australia, this has been best achieved by centres of excellence in adolescent health.

The predictors and consequences of adolescent amphetamine use: findings from the Victoria Adolescent Health Cohort Study

OBJECTIVES

Previous work has highlighted the adverse consequences of early-onset cannabis use. However, little is known about the predictors and effects of early-onset amphetamine use. We set out to examine these issues using a representative cohort of young people followed-up over 11 years in Victoria, Australia.

METHODS

A stratified, random sample of 1943 adolescents was recruited from secondary schools across Victoria at age 14-15 years. This cohort was interviewed on eight occasions until the age of 24-25 years (78% follow-up at that age). Cross-sectional associations were assessed using logistic regression with allowance for repeated measures. Both proportional hazards models and logistic regression models were used to assess prospective associations.

RESULTS

Approximately 7% of the sample had used amphetamines by the age of 17 years. Amphetamine use by this age was associated with poorer mental health and other drug use. The incidence of amphetamine use during the teenage years was predicted by heavier drug use and by mental health problems. By young adulthood (age 24-25 years), adolescent amphetamine users were more likely to meet criteria for dependence upon a range of drugs, to have greater psychological morbidity and to have some limitations in educational attainment. Most of these associations were not sustained after adjustment for early-onset cannabis use.

CONCLUSION

Young people in Australia who begin amphetamine use by age 17 years are at increased risk for a range of mental health, substance use and psychosocial problems in young adulthood. However, these problems are largely accounted for by their even earlier-onset cannabis use.

Toward youth friendly services: a survey of young people in primary care

BACKGROUND

The World Health Organization encourages the development of youth friendly services, yet little is known on how youth currently present in general practice.

OBJECTIVE

To describe the perspectives, expectations, and service receipt of young people presenting to family doctors to inform the development of youth friendly services.

DESIGN

Cross-sectional survey.

PARTICIPANTS AND MEASUREMENTS

Consecutive young people attending 26 randomly selected practices were recruited in the waiting rooms. Standardized instruments were used to interview them before their consultation.

RESULTS

Of 501 young people who were approached, 450 participated (91% participation rate). Most had respiratory (26%) or dermatological complaints (18%). When asked to assess their health status, 59% perceived they had neither a physical nor a mental illness. However, 43% stated they had fears about their health problem and 1 in 5 feared it could be life-threatening. Although only 10% presented with psychological complaints, 24% perceived they currently had a mental illness. The most common expectations were treatment (50%) and good communication (42%). Most youth were prescribed medication (60%), but 40% of those who received a prescription had not expected to receive a treatment. A follow-up appointment was offered to 57% of participants.

CONCLUSIONS

This study identifies a gap between young people's perception of illness and their presentations to family doctors. It also highlights unexpected fears, and a mismatch between expectations and service receipt. These findings have implications for family medicine training and for clinical practice. They should inform the development of youth friendly services.

Problem alcohol use in young Australian adults

OBJECTIVE

To examine the extent to which excessive drinking in young adults is associated with alcohol abuse and dependence.

METHOD

Cross-sectional analyses were conducted using data from the eighth wave of the Victorian Adolescent Health Cohort Study, which comprised 1943 Victorians currently aged 24-25 years drawn from 44 secondary schools across the state in 1992. The main outcome measures of interest were short-term risk drinking status (based on daily alcohol consumption) and long-term risk drinking status (based on total weekly alcohol consumption).

RESULTS

Two out of 5 participants drank at moderate to high risk levels for short-term harm. Yet, because young people tend to drink on only 1-2 days a week, fewer (22%) were at moderate to high risk for long-term harm. Although 20% of the participants met criteria for a diagnosis of alcohol abuse or dependence, most of those in the moderate- to high-risk drinking categories were not diagnosed with either alcohol disorder.

CONCLUSION

Excessive alcohol use in one or two sessions a week appears to be common in young Australian adults. While short- and long-term risky drinking is more common in those with an alcohol use disorder, the majority of moderate- and high-risk drinking is done by those who do not meet criteria for an alcohol use disorder.

Pubertal stage and deliberate self-harm in adolescents

OBJECTIVE

To ascertain the association between pubertal stage and deliberate self-harm.

METHOD

Cross-sectional survey of 12- to 15-year-olds in 300 secondary schools in the U.S. state of Washington in February-April 2002 and the Australian state of Victoria in June-August 2002. A total of 3,332 students in grades 7 and 9 provided complete data on episodes of deliberate self-harm in the previous 12 months and pubertal stage. Pubertal stage was assessed with the Pubertal Development Scale.

RESULTS

The prevalence of deliberate self-harm was 3.7% with a more than twofold higher rate in females. Late puberty was associated with a more than fourfold higher rate of self-harm (odds ratio 4.6, 95% confidence interval 1.5-14) after adjustment for age and school grade level. In contrast age had a protective association (odds ratio 0.7, confidence interval 0.4-1.0). The sharpest rises in prevalence across puberty were for self-laceration and self-poisoning in females. Higher rates of depressive symptoms, frequent alcohol use, and initiation of sexual activity largely accounted for the association between self-harm and pubertal stage in multivariate models.

CONCLUSIONS

Puberty is associated with changes in the form and frequency of self-harm. For adolescents with a gap between puberty and brain development, risk factors such as early sexual activity and substance abuse may be particularly potent.

Trajectories of adolescent alcohol and cannabis use into young adulthood

BACKGROUND

Both alcohol and cannabis use carry health risks. Both are commonly initiated in adolescence. To date little research has described trajectories of adolescent cannabis or alcohol use or compared their respective consequences in young adulthood.

METHODS

The design was a 10-year eight-wave cohort study of a state-wide community sample of 1943 Victorians initially aged 14-15 years. Moderate- and high-risk alcohol use was defined according to total weekly alcohol consumption. Moderate- and high-risk cannabis use were defined as weekly and daily use, respectively.

RESULTS

Around 90% of young adults used either alcohol or cannabis. Although an association existed between alcohol and cannabis use, there was a tendency for heavy users to use one substance predominantly at any one time. Weekly or more frequent cannabis use in the absence of moderate-risk alcohol use in teenagers predicted a sevenfold higher rate of daily cannabis use in young adults but only a twofold increase in high-risk alcohol use. Conversely, moderate-risk adolescent alcohol use in the absence of weekly cannabis predicted an approximately threefold increased rate of both high-risk drinking and daily cannabis use in young adulthood. Selective heavy cannabis use in both adolescence and young adulthood was associated with greater illicit substance use and poorer social outcomes in young adulthood than selective alcohol use.

CONCLUSIONS

Heavier teenage cannabis users tend to continue selectively with cannabis use. Considering their poor young adult outcomes, regular adolescent cannabis users appear to be on a problematic trajectory.

Pubertal transitions in health

Puberty is accompanied by physical, psychological, and emotional changes adapted to ensure reproductive and parenting success. Human puberty stands out in the animal world for its association with brain maturation and physical growth. Its effects on health and wellbeing are profound and paradoxical. On the one hand, physical maturation propels an individual into adolescence with peaks in strength, speed, and fitness. Clinicians have viewed puberty as a point of maturing out of childhood-onset conditions. However, puberty's relevance for health has shifted with a modern rise in psychosocial disorders of young people. It marks a transition in risks for depression and other mental disorders, psychosomatic syndromes, substance misuse, and antisocial behaviours. Recent secular trends in these psychosocial disorders coincide with a growing mismatch between biological and social maturation, and the emergence of more dominant youth cultures.

Teen smokers reach their mid twenties

PURPOSE

Most outcome studies of adolescent smokers have focused on tobacco use in the short term. Few have reported on the health of adolescent smokers as they reach young adulthood.

METHODS

The design was a 10-year, eight-wave cohort study of a state-wide community sample of 1943 participants in Victoria, Australia. Participants were initially aged 14 to 15 years. Tobacco use was assessed with self-reported frequency of use and a seven-day retrospective diary. The Fagerstrom Test for Nicotine Dependence was used to define nicotine dependence in young adulthood. A computerized interview assessment was used during the teens and in young adulthood.

RESULTS

Former daily smokers in adolescence accounted for most cases of nicotine dependence and high-dose (10+ cigarettes per day) smoking in young adulthood. Other substance abuse and psychiatric morbidity in young adulthood were also markedly elevated in this group. This was most clearly evident for cannabis dependence, where close to two-thirds of all cases were formerly daily tobacco smokers. Male smokers were more likely to continue as young adults. Persistent symptoms of depression and anxiety during the teens predicted progression to nicotine dependence, as did having a parent smoking daily.

CONCLUSIONS

The poor health outcomes of daily adolescent smokers as they reach young adulthood provide a rationale for greater tobacco control initiatives directed at early users. Clinical interventions might usefully consider factors such as psychiatric morbidity and parental smoking.

Promoting social inclusion in schools: a group-randomized trial of effects on student health risk behavior and well-being

OBJECTIVES

We sought to test the efficacy of an intervention that was designed to promote social inclusion and commitment to education, in reducing among students health risk behaviors and improving emotional well-being.

METHODS

The design was a cluster-randomized trial in 25 secondary schools in Victoria, Australia. The subjects were 8th-grade students (aged 13 to 14 y) in 1997 (n=2545) and subsequent 8th-grade students in 1999 (n=2586) and 2001 (n=2463). The main outcomes were recent substance use, antisocial behavior, initiation of sexual intercourse, and depressive symptoms.

RESULTS

At 4-year follow-up, the prevalence of marked health risk behaviors was approximately 20% in schools in the comparison group and 15% in schools in the intervention group, an overall reduction of 25%. In ordinal logistic regression models a protective effect of intervention was found for a composite measure of health risk behaviors in unadjusted models (odds ratio [OR]= 0.69; 95% confidence interval [CI]= 0.50, 0.95) and adjusted models (OR= 0.71; CI =0.52, 0.97) for potential confounders. There was no evidence of a reduction in depressive symptoms.

CONCLUSION

The study provides support for prevention strategies in schools that move beyond health education to promoting positive social environments.

Consequences of youth tobacco use: a review of prospective behavioural studies

BACKGROUND

Cigarette smoking represents a significant health problem and tobacco has been identified as causing more preventable diseases and premature deaths than any other drug. Although health consequences from smoking have been documented, there has been a surprising lack of research into behavioural consequences.

AIMS

To review what is known of the long-term relationship between patterns of tobacco use prior to age 18 years and behavioural consequences in adulthood.

METHOD

A literature search of electronic abstraction services from 1980 to September 2005 was conducted. To be included in the review, studies had to have large, representative samples, be longitudinal studies with baseline age under 18 years and follow-up age 18 years or older and clarify effects due to attrition, leaving 16 articles that met the inclusion criteria. Two reviewers evaluated each paper.

FINDINGS

Adolescent tobacco use predicts a range of early adult social and health problems. Surprisingly few studies met the inclusion criteria. The limited evidence available suggests that adolescent tobacco smoking increases the likelihood of early adult tobacco use and the initiation of alcohol use or the development of alcohol-related problems. The link between adolescent tobacco use and subsequent cannabis use was not resolved convincingly from the studies summarized. The effects of tobacco use on later illicit drug use tended to fall away when adjusting for underlying risk factors. Existing studies of the effects of tobacco use on later mental health have many limitations. Nevertheless, a finding that youth tobacco use may predict subsequent mental health problems deserves further investigation. The possible effects of tobacco use on academic/social problems and sleep problems also warrant further investigation.

CONCLUSION

This review highlights links between youth tobacco use and subsequent behavioural and mental health problems. It provides health care professionals with evidence of the possible harmful effects of youth tobacco smoking on later social, emotional, and behavioural well-being.

Youth alcohol and other drug use in the United States and Australia: a cross-national comparison of three state-wide samples

Although youth drug and alcohol harm minimization policies in Australia are often contrasted with the abstinence and zero tolerance policies adopted in the United States, there has been little research directly comparing youth substance use behaviour in the two countries. Three state representative samples in Victoria, Australia (n = 7898) and in the US states of Oregon (n = 15,224) and Maine (n = 16,245) completed a common cross-sectional student survey. Rates of alcohol use (lifetime alcohol use, recent use in the past 30 days), alcohol use exceeding recommended consumption limits (binge drinking: five or more drinks in a session), other licit drug use (tobacco use), and norm-violating substance use (substance use at school, use in the past 30 days of marijuana or other illicit drug use) were compared for males and females at ages 12-17. Rates were lower (odds ratios 0.5-0.8) for youth in Maine and Oregon compared to Victoria for lifetime and recent alcohol use, binge drinking and daily cigarette smoking. However, rates of recent marijuana use and recent use of other illicit drugs were higher in Maine and Oregon, as were reports of being drunk or high at school. In contradiction of harm minimization objectives, Victoria, relative to the US states of Oregon and Maine, demonstrated higher rates of alcohol use exceeding recommended consumption limits and daily tobacco use. However, findings suggested that aspects of norm-violating substance use (substance use at school, marijuana use and other illicit drug use) were higher in the US states compared to Victoria.

Prevalence of substance use and delinquent behavior in adolescents from Victoria, Australia and Washington State, United States

This article compares prevalence estimates of substance use and delinquent behavior in Washington State, United States and Victoria, Australia, two states chosen for their different policy environments around problem behavior. Few comparisons of international differences on rates of multiple problem behavior exist, and most are based on methods that are not matched, raising the question of whether findings are based on methodological differences rather than actual rate differences. The International Youth Development Study used standardized methods to recruit and administer an adaptation of the Communities That Care Youth Survey to representative state samples of fifth-, seventh-, and ninth-grade students in each state. Rates of delinquent behavior were generally comparable. However, striking differences in substance use were noted, with Victoria students reporting higher rates of alcohol use, alcohol misuse, smoking, and inhalant use, whereas Washington State students reported higher rates of marijuana use. Implications for conducting international comparisons are discussed.

Personality and substance use disorders in young adults

BACKGROUND

There have been no studies of the co-occurrence of personality and substance use disorders in young community-dwelling adults.

AIMS

To examine the association between DSM-IV personality disorders and substance use disorders in a large representative sample of young community-dwelling participants.

METHOD

Young Australian adults (n=1520, mean age=24.1 years) were interviewed to determine the prevalence of substance use disorders; 1145 also had an assessment for personality disorder.

RESULTS

The prevalence of personality disorder was 18.6% (95% CI 16.5-20.7). Personality disorder was associated with indices of social disadvantage and the likely presence of common mental disorders. Independent associations were found between cluster B personality disorders and substance use disorders. There was little evidence for strong confounding or mediating effects of these associations.

CONCLUSIONS

In young adults, there are independent associations between cluster B personality disorders and substance use disorders.

Concern about tall stature during adolescence and depression in later life

OBJECTIVE

This retrospective cohort study aimed to examine the long-term psychosocial outcomes for women assessed or treated during adolescence for tall stature.

METHOD

Women assessed or treated for tall stature identified from the records of Australian paediatricians were eligible to participate. Psychosocial outcomes were measured using the depression, mania and eating disorders modules of the Composite International Diagnostic Interview (CIDI), the SF-36, and an index of social support.

RESULTS

There was no significant difference between treated and untreated women in the prevalence of 12 month or lifetime major depression, eating disorders, scores on the SF-36 mental health summary scale, or the index of social support. However, compared with the findings of population-based studies, the prevalence of major depression in both treated and untreated tall girls was high (12 month prevalence: untreated 10.7%, treated 11.2%; lifetime prevalence: untreated 29.4%, treated 26.6%). Factors significantly associated with lifetime major depression in this study were self-reported difficulties during adolescence being the reason for seeking a medical assessment of height (OR 2.25, 95% CI 1.4-3.6) and a negative experience of the assessment or treatment procedures (OR 2.04, 95% CI 1.4-3.0).

CONCLUSION

Long-term follow-up of a large cohort of tall girls showed that psychological outcomes among both treated and untreated women were poor and that the intended psychosocial benefit of treatment may not have been realized. The findings highlight the importance of attending to the mental health of adolescents presenting for management of conditions where self-concept and body image are a primary focus.

Dimensional characteristics of DSM-IV personality disorders in a large epidemiological sample

OBJECTIVE

To assess the five-factor model (FFM) characteristics of young adults with Diagnostic Statistical Manual-IV (DSM-IV) personality disorders in a large community study.

METHOD

As part of the eighth wave of a cohort study, 1469 young adults (mean age: 24 years) completed the NEO-five factor inventory, 1145 of whom also had an informant-based personality disorder assessment.

RESULTS

The prevalence of personality disorder was 18.6% (95% CI: 16.5-20.7). There were consistent positive associations with neuroticism and negative associations with agreeableness across all three clusters of personality disorder.

CONCLUSION

In young adults, high neuroticism and low agreeableness are consistent dimensional characteristics of all personality disorder clusters.

A comparison of self-reported puberty using the Pubertal Development Scale and the Sexual Maturation Scale in a school-based epidemiologic survey

PURPOSE

To examine concordance between two self-reported measures of puberty: Sexual Maturation Scale (SMS) and Pubertal Development Scale (PDS) and their acceptability to adolescents.

METHODS

Participants of a school-based study in grades 5, 7 and 9 were classified into one of 5 pubertal stages using each method.

RESULTS

2864 students (age 9-16 years) participated. Agreement was moderate for males (kappa 0.42, 95% CI 0.39, 0.45) and females (kappa 0.57, 95% CI 0.53, 0.61). Concordance within one stage was excellent (females 97%, males 89%), with discrepancies due to females being classified one stage later on the PDS (26%) and males one stage earlier (32%). There were more missing data for the SMS (13%) than the PDS (4%).

CONCLUSIONS

Given the level of concordance and difficulties of using the drawings in a school-based survey, we would recommend the PDS as an alternative to assess pubertal status in epidemiological studies.

Confidential health care for adolescents: reconciling clinical evidence with family values

Community debate about confidential health care for adolescents was triggered recently by the federal government's proposal to allow parents of teenagers aged 16 years and under access to their children's Health Insurance Commission data without their consent. Extensive research evidence highlights the importance of confidentiality in promoting young people's access to health care, particularly for sensitive issues such as mental and sexual health, and substance use. Involving parents is important, but evidence for any benefit from mandatory parental involvement is lacking. The law recognises the rights of mature minors to make decisions about their medical treatment and to receive confidential health care; however, the doctor must weigh up certain factors to assess maturity and ensure that confidentiality around such treatment will be in the young person's best interests. Evaluation of maturity must take into account characteristics of the young person, gravity of the proposed treatment, family factors, and statutory restrictions.

Reverse gateways? Frequent cannabis use as a predictor of tobacco initiation and nicotine dependence

AIMS

To examine the risk posed by cannabis use in young people for tobacco use disorders. Specifically we examined whether cannabis use in non-smokers predicted later initiation of tobacco use and whether cannabis use predicted later nicotine dependence in tobacco users.

DESIGN

A 10-year eight-wave cohort study.

SETTING

State of Victoria, Australia.

PARTICIPANTS

A community sample of 1943 participants initially aged 14-15 years.

MEASUREMENTS

Self-report of tobacco and cannabis use was assessed in the teens using a computerized interview assessment and in young adulthood with a CATI assessment. The Fagerström Test for Nicotine Dependence was used to define nicotine dependence.

FINDINGS

For teen non-smokers, at least one report of weekly cannabis use in the teens predicted a more than eightfold increase in the odds of later initiation of tobacco use (OR 8.3; 95% CI 1.9-36). For 21-year-old smokers, not yet nicotine-dependent, daily cannabis use raised the odds of nicotine dependence at the age of 24 years more than threefold (OR 3.6, 1.2, 10) after controlling for possible confounders, including level of tobacco use and subsyndromal signs of nicotine dependence.

CONCLUSIONS

Weekly or more cannabis use during the teens and young adulthood is associated with an increased risk of late initiation of tobacco use and progression to nicotine dependence. If this effect is causal, it may be that a heightened risk of nicotine dependence is the most important health consequence of early frequent cannabis use.

A picture of Australia's children

Do we have a clear enough picture to guide rational health and social policy responses?

Association between the COMT Val158Met polymorphism and propensity to anxiety in an Australian population-based longitudinal study of adolescent health

OBJECTIVES

Catechol-O-methyltransferase plays a central role in the metabolism of biogenic amines such as norepinephrine, dopamine and serotonin. Functional studies have demonstrated a dose relationship between ValMet genotypes and catechol-O-methyltransferase activity. Compared with the ValVal genotype, the ValMet and MetMet genotypes result in two- and four-fold reductions in catechol-O-methyltransferase activity, respectively. Two recent reports have observed the association between the MetMet genotype and risk of anxiety in adult populations. We examined the association between the ValMet genotypes and propensity to anxiety across adolescence.

METHODS

Participants were drawn from an eight-wave study of the mental and behavioural health of over 2000 young Australians followed from 14 to 24 years of age (Victorian Adolescent Health Cohort Study, 1992 to present). DNA was received from 962 participants using a cheek swab collection method.

RESULTS

The odds of reporting persistent episodic anxiety (phobic avoidance, panic attacks) were doubled among carriers of the MetMet genotype (odds ratio 2.0, 95% confidence interval 1.1-3.4, P=0.014). A dose relationship between additional copies of the Met allele and persistent episodic anxiety was also observed (1.5, 1.1-1.94, P=0.007). Stratification by sex showed that the risk effect of the Met allele was among females only. No association was observed for measures of neuroticism, persistent generalized anxiety, or a composite measure of psychiatric distress.

CONCLUSION

These data replicate previous findings suggesting association between the ValMet polymorphism and specific expressions of anxiety among females.

Predicting death in young offenders: a retrospective cohort study

OBJECTIVE

To examine predictors of death in young offenders who have received a custodial sentence using data routinely collected by juvenile justice services.

DESIGN

A retrospective cohort of 2849 (2625 male) 11-20-year-olds receiving their first custodial sentence between 1 January 1988 and 31 December 1999 was identified.

MAIN OUTCOME MEASURES

Deaths, date and primary cause of death ascertained from study commencement to 1 March 2003 by data-matching with the National Death Index; measures comprising year of and age at admission, sex, offence profile, any drug offence, multiple admissions and ethnic and Indigenous status, obtained from departmental records.

RESULTS

The overall mortality rate was 7.2 deaths per 1000 person-years of observation. Younger admission age (hazard ratio [HR], 1.4; 95% CI, 1.0-1.9), repeat admissions (HR, 1.8; 95% CI, 1.1-2.9) and drug offences (HR, 1.5; 95% CI, 1.0-2.1) predicted early death. The role of ethnicity/Aboriginality could only be assessed in cohort entrants from 1996 to 1999. The Asian subcohort showed higher risk of death from drug-related causes (HR, 2.5; 95% CI, 1.1-5.5), more drug offences (relative risk ratio [RRR], 13; 95% CI, 8.5-20.0) and older admission age (oldest group v youngest: RRR, 9.3; 95% CI, 1.3-68.0) than non-Indigenous Australians. Although higher mortality was not identified in Indigenous Australians, this group was more likely to be admitted younger (oldest v youngest: RRR, 0.31; 95% CI, 0.15-0.63) and experience repeat admissions (RRR, 1.6; 95% CI, 1.0-2.4).

CONCLUSIONS

Young offenders have a much higher death rate than other young Victorians. Early detention, multiple detentions and drug-related offences are indicators of high mortality risk. For these offenders, targeted healthcare while in custody and further mental healthcare and social support after release appear essential if we are to reduce the mortality rate in this group.

Puberty and the onset of substance use and abuse

OBJECTIVE

Substance abuse remains one of the major threats to adolescent health in Western cultures. The study aim was to ascertain the extent of association between pubertal development and early adolescent substance use.

METHODS

The design was a cross-sectional survey of 10- to 15-year-old subjects in the states of Washington, United States, and Victoria, Australia. Participants were 5769 students in grades 5, 7, and 9, drawn as a 2-stage cluster sample in each state, and the questionnaire was completed in the school classrooms. The main outcomes of the study were lifetime substance use (tobacco use, having been drunk, or cannabis use), recent substance use (tobacco, alcohol, or cannabis use in the previous month), and substance abuse (daily smoking, any binge drinking, drinking at least weekly, or cannabis use at least weekly).

RESULTS

The odds of lifetime substance use were almost twofold higher (odds ratio [OR]: 1.7; 95% confidence interval [CI]: 1.4-2.1) in midpuberty (Tanner stage III) and were threefold higher (OR: 3.1; 95% CI: 2.4-4.2) in late puberty (Tanner stage IV/V), after adjustment for age and school grade level. Recent substance use was moderately higher (OR: 1.4; 95% CI: 1.0-1.9) in midpuberty and more than twofold higher (OR: 2.3; 95% CI: 1.7-3.3) in late puberty. The odds of substance abuse were twofold higher (OR: 2.0; 95% CI: 1.2-3.2) in midpuberty and more than threefold higher (OR: 3.5; 95% CI: 2.2-5.4) in late puberty. Reporting most friends as substance users was more likely in the later stages of pubertal development, a relationship that accounted in part for the association found between later pubertal stage and substance abuse.

CONCLUSIONS

Pubertal stage was associated with higher rates of substance use and abuse independent of age and school grade level. Early maturers had higher levels of substance use because they entered the risk period at an earlier point than did late maturers. The study findings support prevention strategies and policies that decrease recreational substance use within the peer social group in the early teens.

Prematurity at birth and adolescent depressive disorder

Association between prematurity/low birthweight and adolescent depressive disorder studied using a case-control design within a prospective cohort study of 2032 adolescents. Odds for depressive disorder were 11-fold (95% CI 2-62) higher for the premature/low-birthweight participants after regression adjustment for major confounding factors. For premature/low-birthweight females, cumulative rates of depressive disorder over 30 months were 15.2% (95% CI 11.1-20.5) v. 1.8% (95% CI 1.6-2.1) in those with normal deliveries. Physiological adaptations in utero before full term may be implicated causally in some cases of depression in adolescence.

Youth health research ethics: time for a mature-minor clause?

Research into adolescent health issues is hampered by absolute requirements for parental consent. Society's recognition of adolescents' autonomy and decision-making capacity has been embodied in the legal recognition of the mature minor's right to make decisions on matters affecting his or her life. Psychological research indicates that young people from 14 years have decision-making capacity. US and UK research ethics guidelines acknowledge the mature-minor principle, but Australian guidelines are out of step with international practice. An absolute requirement for parental consent in Australian research ethics guidelines is potentially unethical if it denies mature adolescents' autonomy and is a barrier to participation, study validity and improved health outcomes through research findings. There are grounds for considering a mature-minor clause in the National Health and Medical Research Council research ethics guidelines, particularly in the context of youth participation in minimal-risk research.

Nicotine dependence in a prospective population-based study of adolescents

Dopamine is a key neurotransmitter of the mesolimbic reward pathway in the human brain, and tyrosine hydroxylase (TH) is the rate-limiting enzyme in dopamine biosynthesis. Consequently, the gene encoding TH is a strong candidate for involvement in the genetic component of addiction. The importance of this gene in nicotine dependence is supported by many studies showing a link between nicotine administration and TH expression. A functional tetranucleotide repeat polymorphism within intron 1 of the TH gene (HUMTH01-VNTR) has been shown to modify tobacco use in two independent Caucasian samples from the USA and Australia. Using information drawn from an eight-wave Australian population-based longitudinal study of adolescent health, we tested the effect of the HUMTH01-VNTR on nicotine dependence. Comparisons were made between dependent smokers and non-dependent smokers. These data provide further support for a protective association between the K4 allele and dependent smoking (odds ratio 0.54, 95% confidence interval 0.28-1.0). No associations were observed at any of three other common TH polymorphisms (rs6356, rs6357 and HUMTH01-PstI). Including these data, three independent studies, two of which use identical phenotypes, have now identified a protective relationship between the K4 allele of the functional HUMTH01-VNTR polymorphism and high-level smoking.

Adolescent substance use: beware of international comparisons

PURPOSE

To compare prevalence estimates of adolescents' cigarette, alcohol and marijuana use from one Australian and two U.S. surveys, and to consider the effect of methodological differences on reported use.

METHODS

Secondary analysis of data from the Australian Child and Adolescent Component of the National Survey of Mental Health and Well-being (NSMHWB, 1998), the U.S. Youth Risk Behavior Survey (YRBS, 1999), and National Household Survey on Drug Abuse (NHSDA, 1998). Prevalence estimates and 95% confidence intervals were derived for three substance use behaviors. Differences between estimates were considered statistically significant if the 95% confidence intervals did not overlap.

RESULTS

When Australian and U.S. adolescents were compared using NSMHWB and YRBS data, the former were generally found to be less likely to report using cigarettes, alcohol and marijuana than the latter. However, when NHSDA was used as the comparator, the prevalence of substance use among Australian adolescents was either no different from, or greater than, that of U.S. adolescents. Likely explanations for the discrepant findings include the population focus (i.e., whether the survey targeted only young people or adults as well), sampling issues (i.e., whether school-based and household-based sampling frames introduced different biases in terms of who was likely to be absent when the survey was administered), response rates, the survey context (i.e., whether school-based and household-based survey administration methods promoted different kinds of response behavior), the wording of questions and the precision of estimates of the different surveys.

CONCLUSIONS

Cross-national data on adolescent substance use should be interpreted cautiously. Cross-national comparisons that are done well (i.e., using standard, uniform approaches) can be invaluable in highlighting worthwhile policy directions; cross-national comparisons that are done poorly may lead to erroneous assumptions.

Life events and early onset depression: cause or consequence?

BACKGROUND

Adverse life events prior to episodes of depression are assumed to play a causal role. Earlier studies have, however, not adequately controlled for the potential confounding effects of previous depression.

METHOD

A two-phase study was nested within a six-wave population based cohort study of 1947 adolescents. Interviews at two assessment phases with the CIS-R and CIDI were used to generate ICD-10 diagnoses of depressive disorder. Life events with longer-term contextual threat were reported for the 6 months before first diagnosis and categorized on the basis of participant appraisal as negative and neutral/positive in effects. Previous depressive and anxiety symptoms were measured 6 months earlier.

RESULTS

Pre-existing depressive and anxiety symptoms predicted later events, increasing three-fold the risks for both neutral/positive and negative events in females and increased seven-fold the risk of negative events in males. Life events in turn predicted the onset of depressive disorder independently of previous symptoms. Single negative events held an over five-fold elevated risk and multiple events an almost eight-fold higher risk. Personal threat and loss were associated with disorder in females but not males.

CONCLUSIONS

The findings are consistent with a causal role for life events in early episodes of depression. The association also reflects a reciprocal relationship in which earlier symptoms predict later events, perhaps as a result of an individual's attempts to change unfavourable social circumstances.

The outcome of adolescent eating disorders: findings from the Victorian Adolescent Health Cohort Study

The study aimed to ascertain the outcome of adolescent onset eating disorders in a representative cohort of females. The design was a seven wave cohort study conducted over 6 years. 982 female participants from a total sample of 2032 secondary school students initially aged 14-15 years at 44 schools in the state of Victoria Australia. Branched questionnaires (BET) were used for assessing symptoms of eating disorder. A partial syndrome was defined where a subject met two DSM-IV criteria for either anorexia or bulimia nervosa. The revised Clinical Interview Schedule (CIS-R) was used for assessing depression and anxiety, and self-report frequency of use and retrospective diaries for substance use. The mean point prevalence of eating disorders in females between 15-18 years at the partial syndrome level was 2.4 % (1.8-31). At follow-up at the age of 20 years the point prevalence was 3 % (1.9-4.1). In all 8.8 % reported an eating disorder across the six year study period. Eleven percent of those with eating disorder in the teens had persisting disorder at follow-up. In contrast, close to 50 % had high levels of depression and anxiety, a finding that was particularly marked for those with the partial syndrome of bulimia nervosa during the teens. The bulimia group tended to report a higher level of heavy alcohol use at follow-up. Eating disorders at the partial syndrome level are common in young women but most teenage syndromes are brief and self-limiting. The findings are consistent with the partial syndrome of bulimia nervosa being viewed as a variant of affective disorder with different associated behaviours at particular developmental points.

Mortality in young offenders: retrospective cohort study

OBJECTIVES

To estimate overall and cause specific standardised mortality ratios in young offenders.

DESIGN

Comparison of mortality data in cohort of young offenders.

SETTINGS

State of Victoria, Australia.

SUBJECTS

Cohort of young offenders aged 10-20 years with a first custodial sentence from 1 January 1988 to 31 December 1999.

MAIN OUTCOME MEASURES

Deaths ascertained by matching with the national death index, a database containing records of all deaths in Australia since 1980. Death rates in the reference Victorian population used to calculate standardised mortality ratios.

RESULTS

The offender cohort comprised 2621 men and 228 women with 11 333 person years of observation. The median age of first detention was 17.9 years for men and 18.4 years for women. Median follow up was 3.3 years for men and 1.4 years for women. Overall standardised mortality ratio adjusted for age (expressed as a ratio) was 9.4 (95% confidence interval 7.4 to 11.9) for men and 41.3 (20.2 to 84.7) for women. Cause specific standardised mortality ratios for men were 25.7 (17.9 to 36.9) for drug related causes, 9.2 (5.8 to 15) for suicide, and 5.7 (3.6 to 9.2) for non-intentional injury. A quarter of drug related deaths in men aged 15-19 years were in offenders.

CONCLUSIONS

Social policies for young offenders should address both the prevalent drug and mental health problems as well the high levels of social disadvantage.

Adolescent precursors of cannabis dependence: findings from the Victorian Adolescent Health Cohort Study

BACKGROUND

Dependence increases the likelihood of adverse consequences of cannabis use, but its aetiology is poorly understood.

AIMS

To examine adolescent precursors of young-adult cannabis dependence.

METHOD

Putative risk factors were measured in a representative sample (n=2032) of secondary students in the State of Victoria, Australia, six times between 1992 and 1995. Cannabis dependence was assessed in 1998, at age 20-21 years.

RESULTS

Of 1601 young adults, 115 met criteria for cannabis dependence. Male gender (OR=2.6, P < 0.01), regular cannabis use (weekly: OR=4.9; daily: OR=4.6, P=0.02), persistent antisocial behaviour (linear effect P=0.03) and persistent cigarette smoking (linear effect P=0.02) independently predicted cannabis dependence. Neither smoking severity (P=0.83) nor persistent psychiatric morbidity (linear effect P=0.26) independently predicted dependence. Regular cannabis use increased risk only in the absence of persistent problematic alcohol use.

CONCLUSIONS

Weekly cannabis use marks a threshold for increased risk of later dependence, with selection of cannabis in preference to alcohol possibly indicating an early addiction process.

Receipt of psychological or emotional counseling by suicidal adolescents

OBJECTIVE

This study examined utilization of psychological or emotional counseling by suicidal adolescents to answer questions about the extent to which health services can contribute to the prevention of adolescent suicide.

METHOD

The study used data from Wave 1 of the National Longitudinal Study of Adolescent Health, which involved a household-based interview with a nationally representative sample of 15 483 adolescents from grades 7 to 12. Of these, 2482 adolescents were classified as suicidal, as indicated by an affirmative response to the question "During the past 12 months, did you ever seriously think about committing suicide?" For this group, the study asked the following questions: 1) What proportion receives psychological or emotional counseling? 2) What are the sources of this counseling? 3) What factors are associated with receipt of such counseling?

RESULTS

Less than one third (28%) of suicidal adolescents received psychological or emotional counseling. The most common sources of care were private doctors' offices (37%) and schools (34%). Factors associated with receipt of counseling in the past 12 months included age, race, degree of suicidality, depression status, and having had a physical examination during the same period.

CONCLUSIONS

Only one third of those who report suicidal ideation and behavior receive psychological or emotional counseling. Although not all of these young people may identify a need for counseling, this finding still suggests that many of those at risk of harming themselves do not receive professional help. However, on the positive side, those who do use counseling services tend to do so on the basis of their being in the greatest need, rather than their parents' capacity to pay for services. Counseling services have an important role to play in suicide prevention, and a variety of sources of care need to be available. Although counseling services are vital, a range of other strategies is necessary to reduce the youth suicide rate.

Transitions in an imperfectly observed binary variable: depressive symptomatology in adolescents

We describe a methodology for analysing transitions over time in a binary outcome variable that is subject to misclassification (that is, measurement error). Logistic regression models for transition events in the true underlying state are combined with estimates of probabilities of misclassification of the underlying state. The model is based on the Markovian assumption that the probabilities of transition in the underlying state at a given time depend only on the underlying state at the previous time. Hence we estimate odds-ratio effects for transitions that are adjusted for the effect of misclassification. Comparing these adjusted estimates with estimates that are obtained without taking misclassification into account indicates that the latter can be biased either toward or away from the null. For the estimates to exist, certain restrictions on the observed data and misclassification probabilities need to be met. If these restrictions are not satisfied then the conclusion from the analysis is that all observed transition events can be explained solely by the error in outcome assessment, in which case it is likely that an aspect of the model is incorrect. The motivation for this work comes from an analysis of transitions in depression status for a cohort of Australian teenagers participating in a longitudinal study of adolescent health.

Cannabis use and mental health in young people: cohort study

OBJECTIVE

To determine whether cannabis use in adolescence predisposes to higher rates of depression and anxiety in young adulthood.

DESIGN

Seven wave cohort study over six years.

SETTING

44 schools in the Australian state of Victoria.

PARTICIPANTS

A statewide secondary school sample of 1601 students aged 14-15 followed for seven years.

MAIN OUTCOME MEASURE

Interview measure of depression and anxiety (revised clinical interview schedule) at wave 7.

RESULTS

Some 60% of participants had used cannabis by the age of 20; 7% were daily users at that point. Daily use in young women was associated with an over fivefold increase in the odds of reporting a state of depression and anxiety after adjustment for intercurrent use of other substances (odds ratio 5.6, 95% confidence interval 2.6 to 12). Weekly or more frequent cannabis use in teenagers predicted an approximately twofold increase in risk for later depression and anxiety (1.9, 1.1 to 3.3) after adjustment for potential baseline confounders. In contrast, depression and anxiety in teenagers predicted neither later weekly nor daily cannabis use.

CONCLUSIONS

Frequent cannabis use in teenage girls predicts later depression and anxiety, with daily users carrying the highest risk. Given recent increasing levels of cannabis use, measures to reduce frequent and heavy recreational use seem warranted.

Mental health of teenagers who use cannabis. Results of an Australian survey

BACKGROUND

There is concern in the community about increasing cannabis use and its potential effect on health.

AIMS

To ascertain the prevalence of cannabis use among Australian adolescents, associations with mental health problems, risk behaviours and service use.

METHOD

Examination of data from a national representative sample of households comprising 1261 adolescents aged 13-17 years. Parents completed a psychiatric interview and questionnaires while adolescents completed questionnaires.

RESULTS

One-quarter of the adolescents in the sample had used cannabis. There were no gender differences. Use increased rapidly with age, was more common in adolescents living with a sole parent and was associated with increased depression, conduct problems and health risk behaviours (smoking, drinking) but not with higher use of services.

CONCLUSIONS

Cannabis use is very prevalent. The association with depression, conduct problems, excessive drinking and use of other drugs shows a malignant pattern of comorbidity that may lead to negative outcomes.

Cannabis dependence in young adults: an Australian population study

OBJECTIVES

The symptomatology of cannabis dependence remains ill-defined and its importance controversial. Compared with alcohol dependence, the symptom profile of cannabis dependence has received little attention. We aimed to (a) report cannabis use in a representative population of young adults, (b) examine cannabis dependence symptoms according to frequency in the dependence syndrome and (c) contrast the symptomatology of cannabis and alcohol syndromes.

METHODS

1601 young adults (mean age 20.7 years) from an Australian longitudinal cohort study (N=2032) were surveyed in 1998. Regular substance users were assessed for DSM-IV cannabis and alcohol dependence. Prevalence estimates allowed for sampling variation and attrition.

RESULTS

Fifty-nine per cent reported life-time use of cannabis, 17% used at least weekly and 7% (11% males, 4% females) met criteria for cannabis dependence. Symptom prevalence in dependent cannabis users was: persistent desire 91%; unintentional use 84%; withdrawal 74%; excessive time obtaining/using 74%; continued use despite health problems 63%; tolerance 21%; and social consequences 18%. The combination of withdrawal, persistent desire and unintentional use was reported by 57%. Dependent cannabis users reported compulsive and out-of-control use more frequently than dependent alcohol users, withdrawal similarly and tolerance considerably less often.

CONCLUSIONS

Cannabis use appears to be normative behaviour in young Australians. Progression beyond weekly use of cannabis carries a significant risk of dependence that should be considered in the public health response. The differing profiles of cannabis and alcohol dependence, particularly with regard to craving, draws attention to the need for further study of cannabis dependence as an important and distinct disorder in young adults.