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Investigating the relationships between cannabis and other drug use, mental health, early-life factors and life-course outcomes: integrative analyses of data from four Australasian cohort studies

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Tags:
Date Commenced:
2011
Project Supporters:

National Health & Medical Research Council - Project Grant|APP1009381

Drug Type:
Project Members: 
image - Richard Mattick
Honorary Professor
Ph 02 9385 0333
image - 1314150062 Hutchinson Delyse 12
Visiting Senior Lecturer
Ph 50148
image - 1314158526 Wendy Swift 013
Dr Wendy Swift
Senior Lecturer
image - Jcopeland Pb Award 1
Honorary Professor
Ph 02 9385 0231
image - 1314149357 Ed Silins 010
Dr Edmund Silins
Conjoint Lecturer
Project Main Description: 

This study was the first of its kind to use integrative data analyses – a highly innovative approach – to pool data from four large and long-running Australasian cohort studies to better understand the link between cannabis use and later-life outcomes. Dramatically improved knowledge of these relationships has created a clearer picture of the interventions required to reduce the harms associated with cannabis use.

Project Collaborators: External: 

Professor Steve Allsop
National Drug Research Institute, Curtin University

Carolyn Coffey
Murdoch Childrens Research Institute, University of Melbourne

Dr David Ferguson
Christchurch Health and Development Study, University of Otago

Professor Wayne Hall
School of Population Health, University of Queensland

Dr Mohammad Hayatbakhsh
School of Population Health, University of Queensland

A/Prof John Horwood
Christchurch Health and Development Study, University of Otago

Doctor Primrose Letcher
Royal Children’s Hospital, Deakin University

Professor Jake Najman
School of Population Health, University of Queensland

Dr Craig Olsson
Murdoch Childrens Research Institute , University of Melbourne

Professor George Patton
Murdoch Childrens Research Institute , University of Melbourne

Doctor Rachel Skinner
Children’s Hospital Westmead, University of Sydney

Elizabeth Spry
Murdoch Childrens Research Institute , University of Melbourne

Dr Robert Tait
Centre for Mental Health Research, Australian National University

Professor John Toumbourou
School of Psychology, Deakin University

Aims: 

This study had the broad aim of producing more comparable and robust findings about the linkages between cannabis use, mental health, other substance use and social development in young people. Specifically, the study aimed to:

  • develop integrative analyses across four large and long-running Australasian cohorts of the linkages between the use of cannabis and secondary school completion, university degree attainment, depression, self harm, other illicit drug use, welfare and dependence
  • obtain pooled estimates of the effect of cannabis use on other drug use, mental health and social development in young people to provide better estimates of the relationships between cannabis use and particular life-course outcomes
  • more fully utilise existing cohort data.
Design and Method: 

The study used an integrative data analyses framework. Data was harmonised from four long-running Australasian cohort studies which span early childhood, adolescence and young adulthood: The Australian Temperament Project (ATP), The Christchurch Health and Development Study (CHDS), The Mater Hospital and University of Queensland Study of Pregnancy (MUSP), and Victorian Adolescent Health Cohort Study(VAHCS). Combined, the studies involve over 12,000 young people.

Progress/Update: 

In 2013:

A consistent metric for the exposure variables and outcomes of interest were established across the cohort studies involved and data harmonised into a single dataset. Two papers completed and prepared for publication (see below). An additional paper commenced which investigated the genetic prediction of early onset cannabis use and young adult outcomes. Two additional papers outlined for possible future work: (1) Child behaviour problems in the prediction of age of cannabis onset; and, (2) Examining the course of cannabis dependence in young adulthood.

Output: 

In 2013:

Hutchinson, M., Silins, E., Mattick. R., Patton, G., Fergusson, D., Hayatbakhsh, M., Toumbourou, J., Olsson, C., Spry, E., Tait, R., Degenhardt, L., Swift, W., Butterworth, P., Horwood, LJ., andthe Cannabis Cohorts Research Consortium (CCRC). Cohort profile: The Cannabis Cohorts Research Consortium (CCRC) Combined and Harmonised Cohort.

Silins, E., Horwood, LJ., Patton, G., Fergusson, D., Olsson, C., Hutchinson, D., Spry, E., Toumbourou, J., Degenhardt, L., Swift, W., Coffey, C., Tait, R., Letcher, P., Copeland, J., Mattick, R., andthe Cannabis Cohorts Research Consortium (CCRC). Young adult sequelae of adolescent cannabis use: An integrative analysis across three Australasian Cohorts.

Study findings presented at the Australian Professional Society on Alcohol and other Drugs Conference (Brisbane, QLD), and at the NIDA International Forum and the College of Problems of Drug Dependence Annual Meeting (San Diego, CA): Silins, E., Olsson, C., Horwood, J., Hutchinson, D., Spry, E., Patton, G., Fergusson, D., Toumbourou, J.W., Mattick, R., & the Cannabis Cohort Research Consortium. Early onset cannabis use and young adult outcomes: An integrative data analysis of three Australasian cohorts.

Further NHMRC funding received to extend the study to investigate adolescent binge-drinking using data from multiple sources.

 

In 2012:

Published paper: Horwood, LJ., Fergusson, D., Coffey, C., Patton, G., Tait, R., Smart, D., Letcher, P., Silins, E., Hutchinson, D. (2012). Cannabis and depression: An integrative data analysis of four Australasian cohorts. Drug and Alcohol Dependence, 126 (3): 369-378.

Two papers were presented at the National Cannabis Conference, 20th September 2012, Brisbane:

(1) Silins, E., Patton, G., Horwood, L. J.,  Fergusson, D., Letcher, P., Coffey, C., Toumbourou, J.,  Hutchinson, D., Degenhardt, L., Swift, W., Hayatbakhsh, M., Mattick, R., Olsson, C., Allsop, S., Copeland, J., Hall, W., Najman, J., Rodgers, B., Skinner, R., Slade, T., Tait, R. Early onset cannabis use and young adult outcomes: A prognostic study across three Australasian cohorts; and,

(2) Olsson, C., Horwood, L. J., Silins, E., Hutchinson, D., Patton, G., Toumbourou, J., Fergusson, D., Mattick, R., Degenhardt, L., Hayatbakhsh, M., Swift, W., Allsop, S., Coffey, C., Copeland, J.,  Hall, W., Najman, J., O’Connor, M., Rodgers, B., Skinner, R., Slade, T., Tait, R. Genetic prediction of early onset cannabis use and young adult outcomes: A consortium based approach to well powered studies of genetic risk.

Benefits: 

This study produced comparable analyses and better estimates of the relationships between early cannabis use and adverse life-course outcomes. The study extends previous research on the link between adolescent cannabis use and problems later in life by integrating data from multiple sources and providing control for a broader range of covariates than possible in traditional meta-analyses. The findings provide stronger evidence of the potential harms of adolescent cannabis use across a number of domains. The prevention or delay of cannabis use in adolescence may have broad health and social benefits. The findings suggest that efforts to reform cannabis legislation should be carefully evaluated to ensure they reduce adolescent cannabis use and prevent potentially adverse developmental effects.

Drug Type: 
Project Status: 
Completed
Year Completed: 
2013