Delyse Hutchinson

Cannabis use and educational achievement: Findings from three Australasian cohort studies

BACKGROUND The associations between age of onset of cannabis use and educational achievement were examined using data from three Australasian cohort studies involving over 6000 participants. The research aims were to compare findings across studies and obtain pooled estimates of association using meta-analytic methods. METHODS Data on age of onset of cannabis use (<15, 15-17, never before age 18) and three educational outcomes (high school completion, university enrolment, degree attainment) were common to all studies. Each study also assessed a broad range of confounding factors. RESULTS There were significant (p<.001) associations between age of onset of cannabis use and all outcomes such that rates of attainment were highest for those who had not used cannabis by age 18 and lowest for those who first used cannabis before age 15. These findings were evident for each study and for the pooled data, and persisted after control for confounding. There was no consistent trend for cannabis use to have greater effect on the academic achievement of males but there was a significant gender by age of onset interaction for university enrolment. This interaction suggested that cannabis use by males had a greater detrimental effect on university participation than for females. Pooled estimates suggested that early use of cannabis may contribute up to 17% of the rate of failure to obtain the educational milestones of high school completion, university enrolment and degree attainment. CONCLUSIONS Findings suggest the presence of a robust association between age of onset of cannabis use and subsequent educational achievement.

Cannabis and depression: An integrative data analysis of four Australasian cohorts☆

BACKGROUND This study presents an integrative data analysis of the association between frequency of cannabis use and severity of depressive symptoms using data from four Australasian cohort studies. The integrated data comprised observations on over 6900 individuals studied on up to seven occasions between adolescence and mature adulthood. METHODS Repeated measures data on frequency of cannabis use (not used/<monthly/≥monthly/≥weekly) and concurrently assessed depression scores were pooled over the four cohorts. Regression models were fitted to estimate the strength of association between cannabis use and depression. Fixed effects regression methods were used to control for confounding by non-observed fixed factors. RESULTS Increasing frequency of cannabis use was associated with increasing depressive symptoms (p<0.001). In the pooled data weekly users of cannabis had depression scores that were 0.32 (95%CI 0.27-0.37) SD higher than non-users. The association was reduced but remained significant (p<0.001) upon adjustment for confounding. After adjustment depression scores for weekly users were 0.24 (95%CI 0.18-0.30) SD higher than non-users. The adjusted associations were similar across cohorts. There was a weak age×cannabis use interaction (p<0.05) suggesting that the association was strongest in adolescence. Attempts to further test the direction of causality using SEM methods proved equivocal. CONCLUSIONS More frequent cannabis use was associated with modest increases in rates of depressive symptoms. This association was stronger in adolescence and declined thereafter. However, it was not possible from the available data to draw a definitive conclusion as to the likely direction of causality between cannabis use and depression.

Assessing evidence for a causal link between cannabis and psychosis: a review of cohort studies.

Over the past five years, the release of cohort studies assessing the link between cannabis and psychosis has increased attention on this relationship. Existing reviews generally conclude that these cohort studies show cannabis has a causal relationship to psychosis, or at least that one cannot be excluded. Few studies have evaluated the relative strengths and limitations of these methodologically heterogeneous cohort studies, and how their relative merits and weaknesses might influence the way the link between cannabis use and psychosis is interpreted. This paper reviews the methodological strengths and limitations of major cohort studies which have looked at the link between cannabis and psychosis, and considers research findings against criteria for causal inference. Cohort studies that assessed the link between cannabis and psychosis were identified through literature searches using relevant search terms and MEDline, PsycINFO and EMBASE. Reference lists of reviews and key studies were hand searched. Only prospective studies of general population cohorts were included. Findings were synthesised narratively. A total of 10 key studies from seven general population cohorts were identified by the search. Limitations were evident in the measurement of psychosis, consideration of the short-term effects of cannabis intoxication, control of potential confounders and the measurement of drug use during the follow-up period. Pre-existing vulnerability to psychosis emerged as an important factor that influences the link between cannabis use and psychosis. Whilst the criteria for causal association between cannabis and psychosis are supported by the studies reviewed, the contentious issue of whether cannabis use can cause serious psychotic disorders that would not otherwise have occurred cannot be answered from the existing data. Further methodologically robust cohort research is proposed and the implications of how evidence informs policy in the case of uncertainty is discussed.

Body Dissatisfaction and Eating Disturbances in Early Adolescence: A Structural Modeling Investigation Examining Negative Affect and Peer Factors.

This study tested five proposed models of the relationship of negative affect and peer factors in early adolescent body dissatisfaction, dieting, and bulimic behaviors. A large community sample of girls in early adolescence was assessed via questionnaire (X age = 12.3 years). Structural equation modeling (SEM) indicated that negative affect mediated the relationship between body dissatisfaction and bulimic behaviors. Body dissatisfaction also contributed independently to the concurrent prediction of bulimic behaviors. The proposed pathways from dieting to negative affect and dieting to bulimic behaviors were not supported. However, perceived peer influence, perceived weight-related teasing, and the self-reported eating behaviors of friendship clique members all contributed significantly to the concurrent prediction of individual eating pathology. These findings highlight the importance of negative affect and both perceived and actual peer attitudes and behaviors in early adolescent eating pathology.

Substance use, psychological distress and violence among pregnant and breastfeeding Australian women

Objective: To identify the population prevalence and demographic characteristics of pregnant and/or breastfeeding Australian women who use licit and illicit substances and their experience of psychological distress and violence.

Do maternal parenting practices predict problematic patterns of adolescent alcohol consumption

OBJECTIVE This study examines whether a mothers style of parenting at child age 5 years predicts problematic patterns of drinking in adolescence, after controlling for relevant individual, maternal and social risk factors. METHODS Data were used from the Mater-University Study of Pregnancy, an Australian longitudinal study of mothers and their children from pregnancy to when the children were 14 years of age. Logistic regression analyses examined whether maternal parenting practices at child age 5 predicted problematic drinking patterns in adolescence, after controlling for a range of confounding covariates. RESULTS Physical punishment at child age 5 did not predict adolescent alcohol problems at follow-up. Results indicated that low maternal control at child age 5 predicted adolescent occasional drinking patterns at age 14. More frequent maternal partner change coupled with lower levels of control was the strongest predictor of more problematic patterns of drinking by adolescents. CONCLUSIONS These findings highlight the importance of family structure and level of parental control in the development of problematic patterns of drinking in adolescence.

Illicit drug use before and during pregnancy at a tertiary maternity hospital 2000–2006

INTRODUCTION AND AIMS To study the prevalence of use of illicit drugs by women of reproductive age before and during pregnancy and the changes in rates of illicit drug use in pregnancy over recent years. DESIGN AND METHODS All pregnant women attending the public antenatal clinic over a 7 year period (2000-2006) were routinely interviewed about their use of illicit drugs by a midwife at the antenatal booking visit. MEASUREMENTS Records for 25,049 women, who self-reported previous and current use of cannabis, amphetamines, ecstasy and heroin, were included in the study. RESULTS Cannabis was the most common illicit drug used before and during pregnancy; 9.3% of women were engaged in regular use prior to pregnancy and 2.5% were users during pregnancy. A very low proportion of women reported use of amphetamines, ecstasy or heroin in pregnancy. There was an increase in ever regular use and any past use of cannabis, amphetamines and ecstasy over time. CONCLUSIONS The prevalence of illicit drug use by young women prior to becoming pregnant is of concern. While pregnancy appears to be a strong motivator for women to cease substance use, there is a need to study whether women resume drug use after their baby is born.

Adolescent substance use and educational attainment: An integrative data analysis comparing cannabis and alcohol from three Australasian cohorts

BACKGROUND The relative contributions of cannabis and alcohol use to educational outcomes are unclear. We examined the extent to which adolescent cannabis or alcohol use predicts educational attainment in emerging adulthood. METHODS Participant-level data were integrated from three longitudinal studies from Australia and New Zealand (Australian Temperament Project, Christchurch Health and Development Study, and Victorian Adolescent Health Cohort Study). The number of participants varied by analysis (N=2179-3678) and were assessed on multiple occasions between ages 13 and 25. We described the association between frequency of cannabis or alcohol use prior to age 17 and high school non-completion, university non-enrolment, and degree non-attainment by age 25. Two other measures of alcohol use in adolescence were also examined. RESULTS After covariate adjustment using a propensity score approach, adolescent cannabis use (weekly+) was associated with 1½ to two-fold increases in the odds of high school non-completion (OR=1.60, 95% CI=1.09-2.35), university non-enrolment (OR=1.51, 95% CI=1.06-2.13), and degree non-attainment (OR=1.96, 95% CI=1.36-2.81). In contrast, adjusted associations for all measures of adolescent alcohol use were inconsistent and weaker. Attributable risk estimates indicated adolescent cannabis use accounted for a greater proportion of the overall rate of non-progression with formal education than adolescent alcohol use. CONCLUSIONS Findings are important to the debate about the relative harms of cannabis and alcohol use. Adolescent cannabis use is a better marker of lower educational attainment than adolescent alcohol use and identifies an important target population for preventive intervention.

Cohort Profile: The Australian Parental Supply of Alcohol Longitudinal Study (APSALS)

The Australian Parental Supply of Alcohol Longitudinal Study (APSALS) was established in 2010 to investigate the short- and long-term associations between exposure to early parental alcohol provision, early adolescent alcohol initiation, subsequent alcohol use and alcohol-related harms, controlling for a wide range of parental, child, familial, peer and contextual covariates. The cohort commenced with 1927 parent-child dyads comprising Australian Grade 7 school students (mean age = 12.9 years, range = 10.8-15.7 years), and a parent/guardian. Baseline, 1- and 2-year follow-up data have been collected, with > 90% retention, and a 3-year follow-up is under way. The data collected include child, familial, parental and peer factors addressing demographics, alcohol use and supply, parenting practices, other substance use, adolescent behaviours and peer influences. The cohort is ideal for prospectively examining predictors of initiation and progression of alcohol use, which increases markedly through adolescence.

Prevalence and patterns of problematic alcohol use among Australian parents

Objective: Limited research data exists on the prevalence, and characteristics associated with parental alcohol use, particularly in Australia. This study aims to examine the drinking patterns of Australian parents, and to determine whether the drinking pattern differs by family type. The characteristics associated with regular parental alcohol use were also assessed.