Cannabis and depression: an integrative data analysis of four Australasian cohorts

Horwood, L. John, Fergusson, David M., Coffey, Carolyn, Patton, George C., Tait, Robert, Smart, Diana, Letcher, Primrose, Silins, Edmund and Hutchinson, Delyse M. 2012, Cannabis and depression: an integrative data analysis of four Australasian cohorts, Drug and alcohol dependence, vol. 126, no. 3, pp. 369-378, doi: 10.1016/j.drugalcdep.2012.06.002.

Attached Files
Name Description MIMEType Size Downloads

Title Cannabis and depression: an integrative data analysis of four Australasian cohorts
Author(s) Horwood, L. John
Fergusson, David M.
Coffey, Carolyn
Patton, George C.
Tait, Robert
Smart, Diana
Letcher, Primrose
Silins, Edmund
Hutchinson, Delyse M.ORCID iD for Hutchinson, Delyse M.
Journal name Drug and alcohol dependence
Volume number 126
Issue number 3
Start page 369
End page 378
Total pages 10
Publisher Elsevier
Place of publication Shannon, Ireland
Publication date 2012-12-01
ISSN 0376-8716
Keyword(s) cannabis
longitudinal study
integrative data analysis
Summary 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.
Language eng
DOI 10.1016/j.drugalcdep.2012.06.002
Field of Research 170199 Psychology not elsewhere classified
11 Medical And Health Sciences
17 Psychology And Cognitive Sciences
Socio Economic Objective 970117 Expanding Knowledge in Psychology and Cognitive Sciences
HERDC Research category C1.1 Refereed article in a scholarly journal
ERA Research output type C Journal article
Copyright notice ©2012, Elsevier
Persistent URL

Document type: Journal Article
Collections: Faculty of Health
School of Psychology
Connect to link resolver
Unless expressly stated otherwise, the copyright for items in DRO is owned by the author, with all rights reserved.

Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 78 times in TR Web of Science
Scopus Citation Count Cited 89 times in Scopus
Google Scholar Search Google Scholar
Access Statistics: 308 Abstract Views, 1 File Downloads  -  Detailed Statistics
Created: Mon, 28 Nov 2016, 14:24:35 EST

Every reasonable effort has been made to ensure that permission has been obtained for items included in DRO. If you believe that your rights have been infringed by this repository, please contact