The role of cannabis dependence as a risk factor for methamphetamine psychosis

NDARC Staff

Rebecca McKetin and Maree Teesson

Aims

To determine whether cannabis use increases the risk of psychotic symptoms among methamphetamine users.

Progress

This study determined that heavy cannabis use is associated with an increased likelihood of psychotic symptoms among methamphetamine treatment entrants, but that this relationship is largely attributable to factors that co-occur with heavy cannabis use (i.e., heavier methamphetamine use, younger age of initiation into drug use, and comorbid psychiatric disorders). After adjusting for these confounds, no significant relationship was found between level of cannabis use and current psychotic symptoms.

Output

The following NDARC Technical Report has been published:

Hetherington K, McKetin R. (2008). The contribution of cannabis use to psychotic symptoms among methamphetamine treatment entrants. National Drug and Alcohol Research Centre Technical Report No. 294. Sydney, National Drug and Alcohol Research Centre.

The following presentation was given:

McKetin R, Wyzenbeek M, Lubman D, Dawe S, Ali R. (2007). The relationship between cannabis use and the prevalence of psychotic symptoms among dependent methamphetamine users. World Psychiatric Association Congress. November 28 – December 1, 2007. Melbourne, Australia.

Funding

Australian Government Department of Health and Ageing