The Dunedin Study - DMHDRU

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Search results for 'cannabis'

Meier, M.H., Hall, W., Caspi, A., Belsky, D.W., Cerda, M., Harrington, H. L., Houts, R., Poulton, R. , Moffitt, T. E. | 2016
Which adolescents develop persistent substance dependence in adulthood? Using population-representative longitudinal data to inform universal risk assessment

Psychological Medicine, 2016, 46(4), 877-889.
http://dx.doi.org/10.1017/S0033291715002482
Our ref: RO688

Show abstract » Importance: Longitudinal studies have shown that youth exposed to particular risks are more likely to develop substance dependence, and these studies point to potential targets for prevention. They do not, however, directly address the pressing public health question of how accurately we can predict the development of persistent substance dependence in the general population. Objective: To determine how accurately childhood and adolescent risk factors can predict persistent substance dependence. Design: A 38-year, prospective, longitudinal study of a representative birth cohort. Setting: The Dunedin Multidisciplinary Health and Development Study of New Zealand. Participants: The study included 1,037 male and female participants. Exposure: Prospectively assessed predictors included family history of substance dependence, childhood psychopathology (conduct disorder, depression), early exposure to substances, frequent substance use in adolescence, sex, and childhood socioeconomic status. Main Outcome Measures: Persistent substance dependence was defined as dependence on one or more of alcohol, tobacco, cannabis, or hard-drugs at three or more assessment ages: ages 21, 26, 32, and 38. Results: An ROC curve analysis showed that a cumulative index of childhood and adolescent risk predicted persistent adult substance dependence with an AUC (area-under-the-curve) of 0.80 a large effect. Daily tobacco use in adolescence was the single best predictor of later persistent substance dependence, accurately identifying 68% of those who developed persistent substance dependence in adulthood. Nearly 1 in 2 adolescents who used tobacco on a daily basis developed severe substance dependence that persisted through early midlife. Conclusions and Relevance: We can predict with considerable accuracy which individuals will develop persistent substance dependence in adulthood based on information obtained in childhood and adolescence. By ascertaining adolescent tobacco use, clinicians, parents, and teachers, can efficiently identify the majority of individuals who will struggle with persistent substance dependence in adulthood.
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Cerda, M., Moffitt, T.E., Meier, M.H., /Harrington, H. L., Houts, R., Ramrakha, S., Hogan, S., Poulton, R., Caspi, A. | 2016
Persistent cannabis dependence and alcohol dependence represent risks for midlife economic and social problems: A longitudinal cohort study

Clinical Psychological Science, 2016, Published online before print 22 March 2016, DOI: 10.1177/2167702616630958.
DOI: 10.1177/2167702616630958
Our ref: RO685

Show abstract » With the increasing legalization of cannabis, understanding the consequences of cannabis use is particularly timely. We examined the association between cannabis use and dependence, prospectively assessed between ages 18 and 38, and economic and social problems at age 38. We studied participants in the Dunedin Longitudinal Study, a cohort (N = 1,037) followed from birth to age 38. Study members with regular cannabis use and persistent dependence experienced downward socioeconomic mobility, more financial difficulties, workplace problems, and relationship conflict in early midlife. Cannabis dependence was not linked to traffic-related convictions. Associations were not explained by socioeconomic adversity, childhood psychopathology, achievement orientation, or family structure; cannabis-related criminal convictions; early onset of cannabis dependence; or comorbid substance dependence. Cannabis dependence was associated with more financial difficulties than was alcohol dependence; no difference was found in risks for other economic or social problems. Cannabis dependence is not associated with fewer harmful economic and social problems than alcohol dependence.
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Meier, M.H., Caspi, A., Cerda, M., Hancox, R. J., Harrington, H. L., Houts, R., Poulton, R., Ramrakha, S., Thomson, W. M., Moffitt, T.E. | 2016
Associations between cannabis use and physical health problems in early midlife: a longitudinal comparison of persistent cannabis versus tobacco users

JAMA Psychiatry, 2016, Published online first June 01, 2016. doi:10.1001/jamapsychiatry.2016.0637.
https://archpsyc.jamanetwork.com/article.aspx?articleid=2526003
Our ref: RO683

Show abstract » Importance: After major policy changes in the United States, policymakers, health care professionals, and the general public seek information about whether recreational cannabis use is associated with physical health problems later in life. Objective: To test associations between cannabis use over 20 years and a variety of physical health indexes at early midlife.
Design, Setting, and Participants: Participants belonged to a representative birth cohort of 1037 individuals born in Dunedin, New Zealand, in 1972 and 1973 and followed to age 38 years, with 95% retention (the Dunedin Multidisciplinary Health and Development Study). We tested whether cannabis use from ages 18 to 38 years was associated with physical health at age 38, even after controlling for tobacco use, childhood health, and childhood socioeconomic status. We also tested whether cannabis use from ages 26 to 38 years was associated with within-individual health decline using the same measures of health at both ages. Exposures: We assessed frequency of cannabis use and cannabis dependence at ages 18, 21, 26, 32, and 38 years. Main Outcomes and Measures: We obtained laboratory measures of physical health (periodontal health, lung function, systemic inflammation, and metabolic health), as well as self-reported physical health, at ages 26 and 38 years. Results: The 1037 study participants were 51.6% male (n = 535). Of these, 484 had ever used tobacco daily and 675 had ever used cannabis. Cannabis use was associated with poorer periodontal health at age 38 years and within-individual decline in periodontal health from ages 26 to 38 years. For example, cannabis joint-years from ages 18 to 38 years was associated with poorer periodontal health at age 38 years, even after controlling for tobacco pack-years (ß = 0.12; 95% CI, 0.05-0.18; P <.001). Additionally, cannabis joint-years from ages 26 to 38 years was associated with poorer periodontal health at age 38 years, even after accounting for periodontal health at age 26 years and tobacco pack-years (ß = 0.10; 95% CI, 0.05-0.16; P <.001) However, cannabis use was unrelated to other physical health problems. Unlike cannabis use, tobacco use was associated with worse lung function, systemic inflammation, and metabolic health at age 38 years, as well as within-individual decline in health from ages 26 to 38 years. Conclusions and Relevance: Cannabis use for up to 20 years is associated with periodontal disease but is not associated with other physical health problems in early midlife.

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Ramrakha, S., Fergusson, D.M., Horwood, L.J., Dalgard, F., Ambler, A., Kokaua, J., Milne, B.J., Poulton, R. | 2015
Cumulative mental health consequences of acne: 23-year follow-up in a general population birth cohort study

British Journal of Dermatology, 2015, Accepted article published online 27 March, doi:10.1111/bjd.13786.
http://onlinelibrary.wiley.com/doi/10.1111/bjd.13786/abstract
Our ref: RO670

Show abstract » Acne is a highly prevalent condition during adolescence and young adulthood worldwide. School and university samples indicate rates between 12% and 99%, depending on how acne was classified. General population surveys report rates between 14% and 88%.Acne remains a problem in adulthood with rates ranging from 20 to 54%. The effects of acne, regardless of severity, can be debilitating. Studies have shown a range of psychosocial and interpersonal impacts including feelings of shame and loneliness, anger, impaired self-image, attitude and esteem, lack of pride and body satisfaction. It can also affect interpersonal relationships including poor attachment to friends, and not having romantic or sexual relationships. Finally, it has been associated with impaired functioning in other life domains, for example, not thriving at school, decreased participation in sport and exercise and employment problems. Although acne has been associated with negative emotion, impaired ability to function in daily life and a decreased quality of life only a small number of cross-sectional studies have reported an association between acne and specific psychological problems, including symptoms of anxiety and depression and suicide ideation when compared to those with little or no acne. However, no study has examined the relationship of acne and with psychiatric disorder (i.e. psychological distress of greatest severity and clinical interest), nor has research ascertained the cumulative lifecourse effects of acne on psychiatric disorder. In the present study, prospective-longitudinal data from a general population sample was used to determine whether acne preceded poor mental health at the disorder level from adolescence to adulthood. The specific aim of this study was to examine the association between acne and the development of the most common psychiatric disorders of anxiety, depression, alcohol and cannabis dependence.
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Hancox, R. J., Shin, H.H., Gray, A.R., Poulton, R. , Sears, M.R. | 2015
Effects of quitting cannabis on respiratory symptoms

European Respiratory Journal, 2015, Published ahead of print 2 April 2015, doi: 10.1183/09031936.00228914.
doi: 10.1183/09031936.00228914
Our ref: RO665

Show abstract » Smoking cannabis is associated with symptoms of bronchitis. Little is known about the persistence of symptoms after stopping cannabis use. We assessed associations between changes in cannabis use and respiratory symptoms in a population-based cohort of 1037 young adults. Participants were asked about cannabis and tobacco use at ages 18, 21, 26, 32 and 38 years. Symptoms of morning cough, sputum production, wheeze, dyspnoea on exertion and asthma diagnoses were ascertained at the same ages. Frequent cannabis use was defined as .52 occasions over the previous year. Associations between frequent cannabis use and respiratory symptoms were analysed using generalised estimating equations with adjustments for tobacco smoking, asthma, sex and age. Frequent cannabis use was associated with morning cough (OR 1.97, p<0.001), sputum production (OR 2.31, p<0.001) and wheeze (OR 1.55, p<0.001). Reducing or quitting cannabis use was associated with reductions in the prevalence of cough, sputum and wheeze to levels similar to nonusers. Frequent cannabis use is associated with symptoms of bronchitis in young adults. Reducing cannabis use often leads to a resolution of these symptoms.

Media Report:
http://www.dailymail.co.uk/health/article-3087876/How-cannabis-wrecks-lungs-ONE-joint-week-likely-suffer-breathing-problems-smoke-regular-tobacco.html

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Zeng, J., Williams, S.M., Fletcher, D., Cameron, C., Broadbent, J. M. , Shearer, D.M., Thomson, W. M. | 2014
Re-examining periodontal effects of smoking in a birth cohort study with an enhanced analytical approach. Part 1: cross-sectional associations at each age

Journal of Periodontology, 2014, Posted online first, 20 February 2014, DOI: 10.1902/jop.2014.130577.
http://www.joponline.org/doi/pdf/10.1902/jop.2014.130577
Our ref: RO651

Show abstract » Background: Smoking is a major risk factor for periodontal disease. Conventional oral epidemiology approaches have found strong, consistent associations between chronic smoking and periodontal attachment loss (AL) through ages 26, 32, and 38, but those statistical methods disregarded the data’s hierarchical structure. We re-examined the association using hierarchical modelling in order to (1) overcome the limitations of an earlier approach (trajectory analysis) to the data, and (2) determine the robustness of the earlier inferences. Method: Periodontal examinations were conducted at ages 26, 32 and 38 in the Dunedin Multidisciplinary Health and Development Study. The number of participants examined at those three ages were 913, 918 and 913, respectively. Generalized Linear Mixed Modelling with a quasi-binomial approach was used to examine associations between chronic smoking and periodontal attachment loss. Results: At ages 26, 32 and 38, smokers had 3.5%, 12.8% and 23.2% (respectively) greater AL than non-smokers. Regular cannabis use was associated with greater AL after age 32, but not at age 26. Males had more AL than females. Participants with high plaque scores had consistently greater AL; those who were of persistently low SES (socio-economic status) had higher AL at age 32 and 38, but not at age 26. The amount of AL in anteriors was less than in premolars and molars. Gingival bleeding was associated with higher AL at ages 26, 32 and 38. Conclusions: The smoking-periodontitis association is observable with hierarchical modelling, providing strong evidence that chronic smoking is a risk factor for periodontitis.
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Thomson, W. M. , Shearer, D.M., Broadbent, J. M. , Foster-Page, L.A. , Poulton, R. | 2013
The natural history of periodontal attachment loss during the third and fourth decades of life: findings from the Dunedin Study

Journal of Clinical Periodontology, 2013, 40(40), 672-680.
http://onlinelibrary.wiley.com/doi/10.1111/jcpe.12108/pdf
Our ref: RO640

Show abstract » Aim: To describe changes in the occurrence of periodontal attachment loss through ages 26, 32 and 38 in a complete birth cohort. Materials and methods: Systematic periodontal examinations conducted at ages 26, 32 and 38 in a longstanding New Zealand cohort study (N = 1037). Periodontitis extent data were used to assign participants to periodontitis trajectories using group-based trajectory analysis. Results: 831 individuals were periodontally examined at all three ages; the prevalence and extent of attachment loss increased as the cohort aged. Between 26 and 32, one in nine participants had 1+ sites showing new or progressing attachment loss); that proportion almost doubled between ages 32 and 38. Four periodontitis trajectory groups were identified, comprising 54.2%, 31.7%, 11.0% and 3.1% of the cohort; these were termed the no disease, minor disease, moderate disease and extensive disease trajectory groups, respectively. Those who had smoked tobacco at all ages from 15 through 38 were at higher risk of being in the moderate disease or extensive disease trajectory groups. There was a similar risk gradient for those who were in the highest 20% of cannabis usage. Conclusions: Periodontitis commences relatively early in adulthood, and its progression accelerates with age, particularly among smokers.
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Meier, M.H., Caspi, A., Ambler, A., Harrington, H. L., Houts, R., Keefe, R., McDonald, K., Ward, A., Poulton, R. , Moffitt, T.E. | 2012
Persistent Cannabis Users Show Neuropsychological Decline from Childhood to Midlife

PNAS (Proceedings of the National Academy of Sciences of the USA) , 2012, 109(109), E2657-64.
doi:10.1073/pnas.1206820109
Our ref: RO624

Show abstract » Recent reports show that fewer adolescents believe that regular cannabis use is harmful to health. Concomitantly, adolescents are initiating cannabis use at younger ages, and more adolescents are using cannabis on a daily basis. The purpose of the present study was to test the association between persistent cannabis use and neuropsychological decline and determine whether decline is concentrated among adolescent-onset cannabis users. Participants were members of the Dunedin Study, a prospective study of a birth cohort of 1,037 individuals followed from birth (1972/1973) to age 38 y. Cannabis use was ascertained in interviews at ages 18, 21, 26, 32, and 38 y. Neuropsychological testing was conducted at age 13 y, before initiation of cannabis use, and again at age 38 y, after a pattern of persistent cannabis use had developed. Persistent cannabis use was associated with neuropsychological decline broadly across domains of functioning, even after controlling for years of education. Informants also reported noticing more cognitive problems for persistent cannabis users. Impairment was concentrated among adolescent-onset cannabis users, with more persistent use associated with greater decline. Further, cessation of cannabis use did not fully restore neuropsychological functioning among adolescent-onset cannabis users. Findings are suggestive of a neurotoxic effect of cannabis on the adolescent brain and highlight the importance of prevention and policy efforts targeting adolescents.
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Lee, M.H.S., Hancox, R. J. | 2011
Effects of smoking cannabis on lung function

Expert Review of Respiratory Medicine, 2011, 5(5), 537-547.
http://www.expert-reviews.com/doi/abs/10.1586/ers.11.40
Our ref: RO612

Show abstract » Although cannabis (or marijuana) is the worlds most widely-used illicit drug, there has been surprisingly little research into its effects on respiratory health. Part of the problem is the inherent difficulty of studying the long-term effects of an illegal habit. It has often been assumed that smoking cannabis will have similar long-term effects to smoking tobacco. Several recent observational studies suggest that this is not the case and that cannabis has quite different effects on the lung function. There are consistent findings that smoking cannabis is associated with large airway inflammation, symptoms of bronchitis, increased airway resistance and lung hyperinflation. The evidence that smoking cannabis leads to features of chronic obstructive pulmonary disease, such as airflow obstruction and emphysema is not convincing. However, there are numerous case reports of bullous emphysema among cannabis smokers. These findings have not been confirmed in systematic analytical studies and probably represent uncommon adverse effects in very heavy cannabis smokers. There is now additional controversial evidence that cannabis is at least an occasional cause of respiratory malignancies, but again the evidence is inconclusive.
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Hancox, R. J. , Poulton, R., Ely, M., Welch, D., Taylor, D. R. , McLachlan, C. R. , Greene, J. M. , Moffitt, T. E. , Caspi, A., Sears, M.R. | 2010
Effects of cannabis on lung function: a population-based cohort study

European Respiratory Journal, 2010, 35(35), 42-47.
Our ref: RO594

Show abstract » The effects of cannabis on lung function remain unclear and may be different to tobacco. We compared the associations between use of these substances and lung function in a population-based cohort (n=1037). Cannabis and tobacco use were reported at ages 18, 21, 26, and 32 years. Spirometry, plethysmography, and carbon monoxide transfer factor were measured at age 32. Associations between lung function and exposure to each substance were adjusted for exposure to the other substance. Cumulative cannabis use was associated with higher forced vital capacity, total lung capacity, functional residual capacity, and residual volume. Cannabis was also associated with higher airways resistance but not with forced expiratory volume in 1 second, forced expiratory ratio, or transfer factor. These findings were similar amongst those who did not smoke tobacco. By contrast, tobacco use was associated with lower forced expiratory volume in 1 second, lower forced expiratory ratio, lower transfer factor, and higher static lung volumes, but not with airways resistance. Cannabis appears to have different effects on lung function to those of tobacco. Cannabis use was associated with higher lung volumes suggesting hyperinflation and increased large-airways resistance, but there was little evidence for airflow obstruction or impairment of gas transfer.
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Thomson, W. M. , Poulton, R., Broadbent, J. M. , Moffitt, T. E. , Caspi, A., Beck, J.D., Welch, D., Hancox, R. J. | 2008
Cannabis smoking and periodontal disease among young adults

JAMA, 2008, 299(299), 525-531.
Our ref: RO551

Show abstract » Context: Tobacco smoking is a recognized behavioral risk factor for periodontal disease (through its systemic effects), and cannabis smoking may contribute in a similar way. Objective: To determine whether cannabis smoking is a risk factor for periodontal disease. Design and Setting: Prospective cohort study of the general population, with cannabis use determined at ages 18, 21, 26 and 32 years and dental examinations conducted at ages 26 and 32 years. The most recent data collection (at age 32 years) was completed in June 2005. Participants: A complete birth cohort born in 1972 and 1973 in Dunedin, New Zealand, and assessed periodically (with a 96% follow-up rate of the 1015 participants who survived to age 32 years). Compete data for this analysis were available from 903 participants (comprising 89.0% of the surviving birth cohort). Main Outcome Measure: Periodontal disease status at age 32 years (and changes from ages 26 to 32 years) determined from periodontal combined attachment loss (CAL) measured at 3 sites per tooth. Results: Three cannabis exposure groups were determined: no exposure (293individuals, or 32 3%), some exposure (428; 47.4%), and high exposure (182; 20.2%). At age 32 years, 265 participants (29.3%) had 1 or more sites with 4 mm or greater CAL, and 111 participants (12.3%) had 1 or more sites with 5 mm or greater CAL. Incident attachment loss between the ages of 26 and 32 years in the none, some, and high cannabis exposure groups was 6 5%, 112%, and 23.6%, respectively. After controlling for tobacco smoking (measured in pack-years), sex, irregular use of dental services, and dental plaque, the relative risk estimates for the highest cannabis exposure group were as follows: 1.6 (95% confidence interval [CI], 1.2-2.2) for having 1 or more sites with 4 mm or greater CAL; 3.1 (95% CI, 1.5-6.4) for having 1 or more sites with 5 mm or greater CAL; and2.2 (95% CI, 1.2-3.9) for having incident attachment loss (in comparison with those who had never smoked cannabis). Tobacco smoking was strongly associated with periodontal disease experience, but there was no interaction between cannabis use and tobacco smoking in predicting the condition's occurrence. Conclusion: Cannabis smoking may be a risk factor for periodontal disease that is independent of the use of tobacco.
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Fergusson, D.M., Poulton, R., Smith, P.F., Boden, J.M. | 2006
Cannabis and psychosis: a summary and synthesis of the evidence

BMJ, 2006, 332(332), 172-175.
Our ref: RO502

Show abstract » The link between cannabis and psychosis has been extensively investigated in both epidemiological and neuroscientific studies. Epidemiological studies focus on the association between use of cannabis and development of psychosis (box), whereas neuroscientific studies have looked at how cannabis affects neurochemical functioning. However, these two lines of research have been poorly integrated, with little disciplinary cross fertilisation. We have brought together both strands of evidence to give a broader picture.
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Slutske, W., Caspi, A., Poulton, R., Moffitt, T. E. | 2005
Personality and problem gambling: a prospective study of a birth cohort of young adults

Archives of General Psychiatry, 2005, 62(62), 769-775.
Our ref: RO486

Show abstract » Context Individual differences in dimensions of personality may play an important role in explaining risk for disordered gambling behavior as well as the comorbidity between disordered gambling behavior and other substance-related addictive disorders. Objectives To identify the personality correlates of problem gambling in a representative nontreatment-seeking sample, as well as to determine whether these are similar to the personality correlates of other substance-related addictive disorders and whether individual differences in personality might account for the comorbidity between disordered gambling behavior and other substance-related addictive disorders. Design Longitudinal population-based study. Participants A complete birth cohort of young adults born in Dunedin, New Zealand, between April 1, 1972, and March 31, 1973 (N=939; 475 men, 464 women). Main Outcome Measures Multidimensional Personality Questionnaire assessments of personality were obtained at age 18 years; structured interview-based diagnoses of past-year problem gambling and alcohol, cannabis, and nicotine dependence were obtained at age 21 years. Results Problem gambling at age 21 years was associated with higher scores on the higher-order personality dimension of negative emotionality (d=0.90) and with lower scores on the personality dimension of constraint (d=0.72) measured at age 18 years compared with control subjects who did not have a past-year addictive disorder at age 21 years. Problem gambling was also associated with Multidimensional Personality Questionnaire indicators of risk-taking (d=0.50) and impulsivity (d=0.56). The personality profile associated with problem gambling was similar to the profiles associated with alcohol, cannabis, and nicotine dependence. The relations between problem gambling and the substance-related addictive disorders (odds ratios=3.32-3.61) were reduced after controlling for individual differences in personality (odds ratios=1.90-2.32). Conclusions From the perspective of personality, problem gambling has much in common with the addictive disorders, as well as with the larger class of externalizing or disinhibitory disorders. Knowledge gained from the study of common personality underpinnings may be helpful in determining where disordered gambling behavior should reside in our diagnostic classification system.
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Caspi, A., Moffitt, T.E., Cannon, M., McClay, J., Murray, R. M., Harrington, H. L., Taylor, A., Arseneault, L., Williams, B.S., Braithwaite, A., Poulton, R., Craig, I. | 2005
Moderation of the effect of adolescent-onset cannabis use on adult psychosis by a functional polymorphism in the COMT gene: Longitudinal evidence of a gene x environment interaction

Biological Psychiatry, 2005, 57(57), 1117-1127.
Our ref: RO478

Show abstract » Background: Recent evidence documents that cannabis use by young people is a modest statistical risk factor for psychotic symptoms in adulthood, such as hallucinations and delusions, as well as clinically significant schizophrenia. The vast majority of cannabis users do not develop psychosis, however, prompting us to hypothesize that some people are genetically vulnerable to the deleterious effects of cannabis. Methods: In a longitudinal study of a representative birth cohort followed to adulthood, we tested why cannabis use is associated with the emergence of psychosis in a minority of users, but not in others. Results: A functional polymorphism in the catechol-O-methyltransferase (COMT) gene moderated the influence of adolescent cannabis use on developing adult psychosis. Carriers of the COMT valine allele were most likely to exhibit psychotic symptoms and to develop schizophreniform disorder if they used cannabis. Cannabis use had no such adverse influence on individuals with two copies of the methionine allele. Conclusions: These findings provide evidence of a gene environment interaction and suggest that a role of some susceptibility genes is to influence vulnerability to environmental pathogens.
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Stanton, W.R., Flay, B.R., Colder, C.R., Mehta, P. | 2004
Identifying and predicting adolescent smokers' developmental trajectories

Nicotine & Tobacco Research, 2004, 6(6), 843-852.
Our ref: RO499

Show abstract » Very few studies have defined trajectories of smoking. In the present study, we modeled growth in adolescent smoking and empirically identified prototypical trajectories. We conceptualized escalation of smoking as a growth process and modeled rates of change and heterogeneity of these patterns using latent growth mixture modeling. The analysis identified six trajectories with low ambiguity about group membership (early rapid escalators, late rapid escalators, late moderate escalators, late slow escalatorssmokers, stable puffers, and late slow escalatorspuffers). A trajectory of quitters was not identified. We also examined predictors of the smoking trajectories. The predictors were assessed across the adolescent years and included variables related to smoking and other substance use, as well as a range of variables related to sociodemographic factors and mental health. Observed change in the pattern of predictors across age has implications for the mechanism of effect of these variables in relation to smoking trajectories, including predictors that differentiated among daily smokers, variables that may determine the trajectory (e.g., friends smoking), and variables that may result from the trajectory (e.g., marijuana use, less attachment to friends).
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Hussong, A., Curran, P.J., Moffitt, T.E., Caspi, A., Carrig, M.M. | 2004
Substance abuse ensnares young adults in trajectories of antisocial behavior

Development and Psychopathology, 2004, 16(16), 1029-1046.
Our ref: RO471

Show abstract » We examined two hypotheses about the developmental relation between substance abuse and individual differences in desistance from antisocial behavior during young adulthood. The snares hypothesis posits that substance abuse should result in time-specific elevations in antisocial behavior relative to an individual's own developmental trajectory of antisocial behavior, whereas the launch hypothesis posits that substance abuse early in young adulthood slows an individual's overall pattern of crime desistance relative to the population norm during this developmental period. We conducted latent trajectory analyses to test these hypotheses using interview data about antisocial behaviors and substance abuse assessed at ages 18, 21, and 26 in men from the Dunedin Multidisciplinary Health and Development Study (N = 461). We found significant individual variability in initial levels and rates of change in antisocial behavior over time as well as support for both the snares hypothesis and the launch hypothesis as explanations for the developmental relation between substance abuse and crime desistance in young men.
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Arseneault, L. , Cannon, M. , Witton, J. , Murray, R. M. | 2004
Causal association between cannabis and psychosis: examination of the evidence

British Journal of Psychiatry, 2004, 184(184), 110-117.
www.ncbi.nlm.nih.gov/pubmed/14754822
Our ref: RO461

Show abstract » BACKGROUND: Controversy remains as to whether cannabis acts as a causal risk factor for schizophrenia or other functional psychotic illnesses. AIMS: To examine critically the evidence that cannabis causes psychosis using established criteria of causality. METHOD: We identified five studies that included a well-defined sample drawn from population-based registers or cohorts and used prospective measures of cannabis use and adult psychosis. RESULTS: On an individual level, cannabis use confers an overall twofold increase in the relative risk for later schizophrenia. At the population level, elimination of cannabis use would reduce the incidence of schizophrenia by approximately 8%, assuming a causal relationship. Cannabis use appears to be neither a sufficient nor a necessary cause for psychosis. It is a component cause, part of a complex constellation of factors leading to psychosis. CONCLUSIONS: Cases of psychotic disorder could be prevented by discouraging cannabis use among vulnerable youths. Research is needed to understand the mechanisms by which cannabis causes psychosis.
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Begg, D.J., Langley, J.D., Stephenson, S. | 2003
Identifying factors that predict persistent driving after drinking, unsafe driving after drinking, and driving after using cannabis among young adults

Accident Analysis and Prevention, 2003, 35(35), 669-675.
Our ref: RO436

Show abstract » The main aim of this study was to identify adolescent/young adulthood factors that predicted persistent driving after drinking, persistent unsafe driving after drinking, and persistent cannabis use and driving among young adults. It was a longitudinal study of a birth cohort (n=933, 474 males and 459 females) and was based on data collected at ages 15, 18, 21 and 26 years. At each of these ages members of the cohort attended the research unit for a personal interview by a trained interviewer, using a standardised questionnaire. For this study, the data for the outcome measures (persistent driving after drinking, persistent unsafe driving after drinking, and persistent driving after using cannabis) were obtained at ages 21 and 26 years. The main explanatory measures were collected at ages 15, 18, 21 years and included demographic factors (academic qualifications, employment, parenting); personality measures; mental health measures (substance use, cannabis dependence, alcohol dependence, depression); anti-social behaviour (juvenile arrest, aggressive behaviour, court convictions); early driving behaviour and experiences (car and motorcycle licences, traffic crashes). The analyses were conducted by gender. The results showed that females who persisted in driving after drinking (13%, n=61) were more likely than the others to have a motorcycle licence at 18. The males who persisted in driving after drinking (28%, n=135) were more likely than the other males to have some school academic qualifications and to be employed at age 26. Compared to the other males, those who persisted in unsafe driving after drinking (4%, n=17) were more likely to be aggressive at 18 and alcohol dependent at 21. Only six (1%) females persisted in unsafe driving after drinking so regression analyses were not conducted for this group. For persistent driving after using cannabis, the univariate analyses showed that females who persisted with this behaviour tended to have high substance use at 18, cannabis dependence at 21, police contact as a juvenile, and to be a parent at 21. For this group, because of the small numbers (3%, n=13) multivariate analyses were not appropriate. For the males who persisted in driving after using cannabis (14%, n=68) a wide range of variables were significant at the univariate stage. The multivariate analysis showed that the most important factors were dependence on cannabis at 21, at least one traffic conviction before 21, a non traffic conviction before 18, and low constraint at 18. Conclusion: These results show different characteristics were associated with persistence in each of these outcome behaviours. This indicates that different approaches would be required if intervention programmes were to be developed to target these behaviours.
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Arseneault, L., Moffitt, T.E., Caspi, A., Taylor, A. | 2002
The targets of violence committed by young offenders with alcohol dependence, marijuana dependence and schizophrenia-spectrum disorders: findings from a birth cohort

Criminal Behavior and Mental Health, 2002, 12(12), 155-168.
Our ref: RO441

Show abstract » Background: Estimates of who is most at risk from violence by people with mental illness rest mainly on identified patient samples. This study, without such selection bias, examined the targets of violence committed by young adults with as-yet untreated alcohol dependence, marijuana dependence, or schizophrenia-spectrum disorders, to determine the extent to which their victims were co-residents or non-household members. Methods: In a total birth cohort of 21-year-olds (n = 956), past-year prevalence of alcohol dependence, marijuana dependence and schizophrenia-spectrum disorders were diagnosed using standardized DSM-III-R interviews. None of the people with schizophrenia-spectrum disorder has been hospitalized in the past year. Past-year violence and victim targets were measured using self-reports. Results: Compared with controls, cohort members with substance dependence or schizophrenia-spectrum disorders had higher prevalence and frequency rates of assault against co-residents, against non-household members, and also robbery and gang fights. Out of 39, five individuals with schizophrenia-spectrum disorder committed violent street crimes. Persons with substance dependence had similar proportions of violence against co-resident and non-household members, but persons with schizophrenia-spectrum disorders tended to victimize co-residents more than others. Conclusions: At the age when they are most likely to contribute to the communitys violence burden, young untreated offenders with alcohol or marijuana dependence or with schizophrenia-spectrum disorders assault not only co-residents, but others as well, and commit violent street crimes. Families, schoolteachers and primary care physicians have an important potentially preventive role in early identification and treatment of the disorders.
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Arseneault, L., Cannon, M., Poulton, R., Murray, R. M., Caspi, A., Moffitt, T.E. | 2002
Cannabis use in adolescence and risk for adult psychosis: longitudinal prospective study

BMJ, 2002, 325(325), 1212-1213.
Our ref: RO427

Show abstract » The strongest evidence that cannabis use may be a risk factor for later psychosis comes from a Swedish cohort study which found that heavy cannabis use at age 18 increased the risk of later schizophrenia sixfold. This study could not establish whether adolescent cannabis use was a consequence of pre-existing psychotic symptoms rather than a cause. We present the first prospective longitudinal study of adolescent cannabis use as a risk factor for adult schizophreniform disorder, taking into account childhood psychotic symptoms antedating cannabis use.
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Taylor, D.R., Fergusson, D.M., Milne, B.J., Horwood, L.J., Moffitt, T.E., Sears, M.R., Poulton, R. | 2002
A longitudinal study of the effects of tobacco and cannabis exposure on lung function in young adults

Addiction, 2002, 97(97), 1055-1061.
Our ref: RO416

Show abstract » Aim: To assess the possible effects of tobacco and cannabis smoking on lung function in young adults between the ages of 18 and 26. Setting and participants: A group of over 900 young adults derived from a birth cohort of 1037 subjects born in Dunedin, New Zealand in 1972/73 were studied at age 18, 21 and 26 years. Measurements: Cannabis and tobacco smoking were documented at each age using a standardized interview. Lung function, as measured by the forced expiratory volume in one second/vital capacity (FEV1/VC) ratio, was obtained by simple spirometry. A fixed effects regression model was used to analyse the data to take account of confounding factors. Findings When the sample was stratified for cumulative use, there was evidence of a linear relationship between cannabis use and FEV1/VC (P<0.05). In the absence of adjusting for other variables, increasing cannabis use over time was associated with a decline in FEV1/VC with time; the mean FEV1/VC among subjects using cannabis on 900 or more occasions was 7.2%, 2.6% and 5.0% less than non-users at ages 18, 21 and 26, respectively. After controlling for potential confounding factors (age, tobacco smoking and weight) the negative effect of cumulative cannabis use on mean FEV1/VC was only marginally significant (P<0.09). Age (P<0.001), cigarette smoking (P<0.05) and weight (P<0.001) were all significant predictors of FEV1/VC. Cannabis use and daily cigarette smoking acted additively to influence FEV1/VC. Conclusions: Longitudinal observations over 8years in young adults revealed a dose-dependent relationship between cumulative cannabis consumption and decline in FEV1/VC. However, when confounders were accounted for the effect was reduced and was only marginally significant, but given the limited time frame over which observations were made, the trend suggests that continued cannabis smoking has the potential to result in clinically important impairment of lung function.
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Poulton, R., Moffitt, T.E., Harrington, H. L., Milne, B.J., Caspi, A. | 2001
Persistence and perceived consequences of cannabis use and dependence among young adults: implications for policy

New Zealand Medical Journal, 2001, 114(114), 544-547.
Our ref: NZ83

Show abstract » Aims. To document patterns of cannabis use and dependence from late-adolescence through to the midtwenties; to describe perceived consequences of cannabis use among young people; and to consider policy implications of these findings. Methods. This was a longitudinal study of the Dunedin Multidisciplinary Health and Development Study birth cohort with repeated measures of cannabis use at ages 18, 21 and 26 years. Results. Twelve month prevalence rates of cannabis use (just over 50%) and dependence (just under 10%) remained stable between age 21 and 26 years, contrary to an expected decline. Cannabis dependence, as distinct from occasional use, was associated with high rates of harder drug use, selling of drugs and drug conviction. Cumulatively, almost 3/4 of our cohort had tried cannabis by age 26. Young people thought the risk of getting caught using cannabis was trivial, and that using cannabis had few negative social consequences. Conclusions. The persistent high rates of cannabis use and dependence among young New Zealand adults raises important issues for policy makers. Current laws are not particularly effective in deterring use. Whereas occasional use does not appear to present a serious problem, cannabis dependence among users is a serious public health issue that warrants immediate action.
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Taylor, D.R., Poulton, R., Moffitt, T.E., Ramankutty, P., Sears, M.R. | 2000
The respiratory effects of cannabis dependence in young adults

Addiction, 2000, 95(95), 1669-1677.
Our ref: RO364

Show abstract » Aim. To evaluate the relationship between cannabis dependence and respiratory symptoms and lung function in young adults, while controlling for the effects of tobacco smoking. Setting and participants. Nine hundred and forty-three young adults from a birth cohort of 1037 subjects born in Dunedin, New Zealand in 1972/1973 were studied at age 21. Measurements. Standardized respiratory symptom questionnaires were administered. Spirometry and methacholine challenge tests were undertaken. Cannabis dependence was determined using DSM-III-R criteria. Descriptive analyses and comparisons between cannabis-dependent, tobacco-smoking and non-smoking groups were undertaken. Adjusted odds ratios for respiratory symptoms, lung function and airway hyper-responsiveness (PC20) were measured. Findings. Ninety-one subjects (9.7%) were cannabis-dependent and 264 (28.1%) were current tobacco smokers. After controlling for tobacco use, respiratory symptoms associated with cannabis dependence included: wheezing apart from colds, exercise-induced shortness of breath, nocturnal wakening with chest tightness and early morning sputum production. These were increased by 61%, 65%, 72% (all p < 0.05) and 144% (p < 0.01) respectively, compared to non-tobacco smokers. The frequency of respiratory symptoms in cannabis-dependent subjects was similar to tobacco smokers of 1-10 cigarettes/day. The proportion of cannabis-dependent study members with an FEV1/FVC ratio of < 80% was 36% compared to 20% for non-smokers (p = 0.04). These outcomes occurred independently of co-existing bronchial asthma. Conclusion. Significant respiratory symptoms and changes in spirometry occur in cannabis-dependent individuals at age 21 years, even although the cannabis smoking history is of relatively short duration.
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Arseneault, L., Caspi, A., Moffitt, T.E., Taylor, P.J., Silva, P.A. | 2000
Mental disorders and violence in a total birth cohort: Results from the Dunedin Study

Archives of General Psychiatry, 2000, 57(57), 979-986.
Our ref: RO358

Show abstract » Background: We report on mental disorders and violence for a birth cohort of young adults, regardless of their contact with the health or justice systems. Methods: We studied 961 young adults who constituted 94% of a total-city birth cohort in New Zealand, April 1, 1972, through March 31, 1973. Past-year prevalence of mental disorders was measured using standardized DSM III R interviews. Past-year violence was measured using self-reports of criminal offending and a search of official conviction records. We also tested whether substance use before the violent offence, adolescent excessive perceptions of threat, and a juvenile history of conduct disorder accounted for the link between mental disorders and violence. Results: Individuals meeting diagnostic criteria for alcohol dependence, marijuana dependence, and schizophrenia spectrum disorder were 1.9 (95% confidence interval [CI], 1.0-3.5), 3.8 (95% CI, 2.2-6.8), and 2.5 (95% CI, 1.1-5.7) times, respectively, more likely than control subjects to be violent. Persons with at least 1 of these 3 disorders constituted one fifth of the sample, but they accounted for half of the sample's violent crimes (10% of violence risk was uniquely attributable to schizophrenia-spectrum disorder). Among alcohol-dependent individuals, violence was best explained by substance use before the offence; among marijuana-dependent individuals, by a juvenile history of conduct disorder; and among individuals with schizophrenia-spectrum disorder, by excessive perceptions of threat and a history of conduct disorder. Conclusions: In the age group committing most violent incidents, individuals with mental disorders account for a considerable amount of violence in the community. Different mental disorders are linked to violence via different core explanations, suggesting multiple-targeted prevention strategies.
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McGee, R., Williams, S.M., Poulton, R., Moffitt, T.E. | 2000
A longitudinal study of cannabis use and mental health from adolescence to early adulthood

Addiction, 2000, 95(95), 491-503.
Our ref: RO349

Show abstract » AIMS: To examine the longitudinal association between cannabis use and mental health. DESIGN: Information concerning cannabis use and mental health from 15 to 21 years was available for a large sample of individuals as part of a longitudinal study from childhood to adulthood. PARTICIPANTS: Participants were enrolled in the Dunedin Multidisciplinary Health and Development Study, a research programme on the health, development and behaviour of a large group of New Zealanders born between 1 April 1972 and 31 March 1973. MEASUREMENTS: Cannabis use and identification of mental disorder was based upon self- report as part of a general assessment of mental health using a standard diagnostic interview. Daily smoking and alcohol use at age 15 were assessed by self-report. Indices of family socio-economic status, family climate and parent-child interaction were formed using information gathered from parent report and behavioural observations over early childhood. Childhood behaviour problems were assessed by parent and teacher report. Attachment to parents was assessed in adolescence. FINDINGS: Cross-sectional associations between cannabis use and mental disorder were significant at all three ages. Both outcome variables shared similar pathways of low socio-economic status and history of behaviour problems in childhood, and low parental attachment in adolescence. Mental disorder at age 15 led to a small but significantly elevated risk of cannabis use at age 18; by contrast, cannabis use at age 18 elevated the risk of mental disorder at age 21. The latter association reflected the extent to which cannabis dependence and other externalizing disorders at age 21 were predicted by earlier level of involvement with cannabis. CONCLUSIONS: The findings suggest that the primary causal direction leads from mental disorder to cannabis use among adolescents and the reverse in early adulthood. Both alcohol use and cigarette smoking had independent associations with later mental health disorder.
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Reeder, A.I., Alsop, J., Begg, D.J., Nada-Raja, S., McLaren, R.L. | 1998
A longitudinal investigation of psychological and social predictors of traffic convictions among young New Zealand drivers

Transportation Research Part F: Traffic Psychology and Behaviour, 1998, 1(1), 25-45.
Our ref: RO337

Show abstract » The study aimed to determine, irrespective of driver licence status, whether young drivers with traffic conviction records at age 21 years differed from those without, with respect to prior personal characteristics measured around the minimum age of licensure (presently 15 years in New Zealand). From a broad range of psychological and social factors, the strongest and most stable predictors were male gender, part time work, rural residence, marijuana use, estimated driving exposure during the follow up period, and early motorcycle riding. Experiences of riding as a passenger with young drivers or with an alcohol intoxicated adult driver were also significant predictors. Some road safety implications are considered.
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Newman, D.L., Moffitt, T.E., Caspi, A., Silva, P.A. | 1998
Comorbid mental disorders: Implications for clinical treatment and sample selection

Journal of Abnormal Psychology, 1998, 107(107), 305-311.
Our ref: RO314

Show abstract » Disorders from the Diagnostic and Statistical Manual of Mental Disorders (3rd ed., rev.; American Psychiatric Association, 1987) were assessed in a birth cohort of 961 young adults. Comorbid cases exceeded single-disordered cases in chronic history of mental illness, use of treatments, physical health problems, functional interference in daily life, and impaired adaptation across domains such as work, education, health, and social-support networks. Single-disorder cases were also more impaired than nondisordered cases, but comorbid cases were the most severely impaired. Our findings suggest that (a) samples that underrepresent comorbidity (pure single-disorder cases or student samples) will underestimate effect sizes for relations between a disorder and its correlates, whereas samples that overrepresent comorbidity (clinical or adjudicated samples) will overestimate effect sizes, (b) comorbidity is accompanied by complications that challenge treatment planning, compliance, and coordination of service delivery, and (c) comorbidity is associated with physical, educational, and economic problems that make it a broad societal concern.
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Poulton, R., Brooke, M., Moffitt,T.E., Stanton,W.R., Silva, P.A. | 1997
Prevalence and correlates of cannabis use and dependence among young New Zealanders

New Zealand Medical Journal, 1997, 110(110), 68-70.
Our ref: NZ71

Show abstract » Aims. To determine change in patterns of cannabis use in New Zealand in an unselected birth cohort and investigate the relationship between level of cannabis use, violent behaviour and employment history. Method. Prospective longitudinal design using members of the Dunedin Multidisciplinary Health and Development Study at ages 15, 18 and 21 years. Results. Rates of cannabis use increased from 15% (n = 144) at age 15 years to more than half of the sample seen at age 21 years (n = 497; 52.4%). DSM-III-R defined cannabis dependence assessed at age 18 and 21 years increased from 6.6% (n = 61) to 9.6% (n = 91). Males were more likely to use and be dependent on cannabis than females. Early use substantially increased the risk for the development of cannabis dependence in young adulthood. Cross-sectional analysis at age 21 found levels of cannabis use and dependence to be higher among the unemployed and those with a history of violent behaviour. Conclusions. Prevalence rates of cannabis use in young New Zealanders were found to be higher than previously reported. A history of unemployment or of violent behaviour was associated with more frequent cannabis use at age 21. Males were more likely than females to use cannabis frequently and to meet DSM-III-R criteria for dependence at age 21. It is suggested that drug education campaigns should specifically target young males.
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Caspi, A., Begg, D.J., Dickson, N., Langley, J.D., Moffitt, T.E., McGee, R., Silva, P.A. | 1995
Identification of personality types at risk for poor health and injury in late adolescence

Criminal Behavior and Mental Health, 1995, 5(5), 330-350.
Our ref: RO270

Show abstract » In an unselected general birth cohort of 862 18-year-olds, we sought to identify the personality characteristics associated with involvement in each of five different health-risk behaviours (unprotected sexual intercourse with multiple partners, dangerous driving habits, violent crime, alcohol dependence and marijuana dependence) as well as the personality characteristics associated with a syndrome of multiple health-risk behaviours. A unique configuration of traits differentiated youth involved in any given single health-risk behaviour from youth who were not. These youth were more impulsive, aggressive, alienated and tended to experience negative emotions in response to daily hassles. A different unique configuration of traits differentiated youth involved in a syndrome of multiple health-risk behaviours from youth involved in a single or in no health-risk behaviours. These youth were distinguished by a rejection of social norms, danger-seeking, impulsivity, a very low threshhold for negative emotional responses such as anger, irritability und nervous tension, and by little need or capacity for connection to other people. In planning health campaigns, health professionals need to consider the unique psychological make-up of persons most at risk for health-risk behaviours and design programmes that will appeal to them.
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Feehan, M., McGee, R., Nada-Raja, S., Williams, S.M. | 1994
DSM-III-R disorders in New Zealand 18-year-olds

Australian and New Zealand Journal of Psychiatry, 1994, 28(28), 87-99.
Our ref: RO237

Show abstract » The one-year prevalence and correlates of selected DSM-III disorders were determined in a sample of 930 18-year-olds. Using both diagnostic and impairment criteria 340 Individuals (36.6%) were considered to have disorder. The most prevalent disorders were major depressive episode (16.7%), alcohol dependence (10.4%) and social phobia (11.1%). There was a high degree of co-morbidity among disorders; 46% of those with disorder had two or more. The prevalence of disorders was greater for females with the exception of conduct disorder and alcohol or marijuana dependence. A variety of characteristics were associated with disorder including poor social competence, disadvantage and self-rated health status. A third of those with disorder had their problems recognised by a significant-other. The results are presented within the context of a perceived need for research in the area of adolescent and early adult mental health in order to minimise the toll of mental disorder in later life.
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McGee, R., Feehan, M. | 1993
Cannabis use among New Zealand Adolescents [Letter]

New Zealand Medical Journal, 1993, 106(106), 345.
Our ref: NZ67

Show abstract » This letter describes results from the Study on cannabis use among sample members at age 15 and 18 in support of the findings of Fergusson et al on cannabis use in a sample of adolescents in Christchurch, New Zealand.
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Henry, B., Feehan, M., McGee, R., Stanton, W.R., Moffitt, T.E., Silva, P.A. | 1993
The importance of conduct problems and depressive symptoms in predicting adolescent substance use

Journal of Abnormal Child Psychology, 1993, 21(21), 469-480.
Our ref: RO213

Show abstract » The current study assessed the relative importance of conduct problems and depressive symptoms, measured at two ages (11 and 15), for predicting substance use at age 15 in an unselected birth cohort of New Zealand adolescents. Among males, when the relative predictive utility of both conduct problems and depressive symptoms was assessed, only pre-adolescent depressive symptoms were found to predict multiple drug use 4 years later. No predictive relation was found between early symptomatology and later substance use among females. The strongest association between predictors and substance use emerged between age 15 multiple drug use and concurrent conduct problems for both males and females. Finally, both conduct problems and depressive symptoms at age 15 were also found to be associated with concurrent ''self-medication'' among females.
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