Research article
The association between delusional-like experiences, and tobacco, alcohol or cannabis use: a nationwide population-based survey
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* Corresponding author: John J McGrath John_mcgrath@qcmhr.uq.edu.au
1 Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Wacol, QLD 4076, Australia
2 Metro North Mental Health, Royal Brisbane and Women's Hospital, Brisbane, QLD, Australia
3 The University of Queensland Centre for Clinical Research, Brisbane, QLD, Australia
4 Department of Psychiatry, University of Queensland, St Lucia QLD, Australia
5 Princess Alexandra Hospital, Woolloongabba, QLD 4102 Australia
6 National Drug & Alcohol Research Centre, University of New South Wales, NSW, Australia
7 Queensland Brain Institute, University of Queensland, St Lucia, QLD, Australia
BMC Psychiatry 2011, 11:202 doi:10.1186/1471-244X-11-202
Published: 28 December 2011Abstract
Background
Previous population-based studies have found that delusional-like experiences (DLE) are prevalent in the community, and are associated with a wide range of mental health disorders including substance use. The aim of the study was to explore the association between DLE and three commonly used substances - tobacco, alcohol and cannabis.
Methods
Subjects were drawn from the Australian National Survey of Mental Health and Wellbeing 2007. The Composite International Diagnostic Interview was used to identify DLE, common psychiatric disorders, and substance use. We examined the relationship between the variables of interest using logistic regression, adjusting for potential confounding factors.
Results
Of 8 773 participants, 8.4% (n = 776) subjects endorsed one or more DLE. With respect to tobacco use, compared to nonusers, DLE were more common in those who (a) had daily use, (b) commenced usage aged 15 years or less, and (c) those who smoked heavily (23 or more cigarettes per day). Participants with cannabis use disorders were more likely to endorse DLE; this association was most prominent in those with an onset of 16 years or younger. In contrast, the pattern of association between DLE versus alcohol use or dependence was less consistent, however those with early onset alcohol use disorders were more likely to endorse DLE probe items.
Conclusions
While cannabis use disorders have been previously linked with DLE, our findings linking alcohol and tobacco use and DLE suggest that the influence of these substances on psychosis-related outcomes warrants closer scrutiny in longitudinal prospective studies.