Cannabis potency and contamination: a review of the literature

McLaren, Jennifer; Swift, Wendy; Dillon, Paul; Allsop, Steve

doi:10.1111/j.1360-0443.2008.02230.x

Cited by 185 publications

(133 citation statements)

References 43 publications

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“…Taken together, it is plausible that long-term changes in cannabis potency could influence cannabis-related harms (including changes in cannabis admissions to drug treatment). Although the potential health impacts of increasing cannabis potency have been widely acknowledged (McLaren et al 2008;Di Forti et al 2015;Freeman & Winstock, 2015;ElSohly et al 2016;EMCDDA, 2016;UNODC, 2016) we are unaware of any previous attempts to empirically test associations between changes in cannabis potency and population markers of cannabis harms.…”

Section: Introductionmentioning

confidence: 99%

Changes in cannabis potency and first-time admissions to drug treatment: a 16-year study in the Netherlands

et al. 2018

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Background. The number of people entering specialist drug treatment for cannabis problems has increased considerably in recent years. The reasons for this are unclear, but rising cannabis potency could be a contributing factor. Methods. Cannabis potency data were obtained from an ongoing monitoring programme in the Netherlands. We analysed concentrations of δ-9-tetrahydrocannabinol (THC) from the most popular variety of domestic herbal cannabis sold in each retail outlet (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015). Mixed effects linear regression models examined time-dependent associations between THC and first-time cannabis admissions to specialist drug treatment. Candidate time lags were 0-10 years, based on normative European drug treatment data. After adjusting for age, sex and non-cannabis drug treatment admissions, these positive associations were attenuated but remained statistically significant at lags of 5-7 years and were again strongest at 5 years, b = 0.082 (0.052-0.111), p < 0.0001. Conclusions. In this 16-year observational study, we found positive time-dependent associations between changes in cannabis potency and first-time cannabis admissions to drug treatment. These associations are biologically plausible, but their strength after adjustment suggests that other factors are also important.

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Section: Introductionmentioning

confidence: 99%

Changes in cannabis potency and first-time admissions to drug treatment: a 16-year study in the Netherlands

et al. 2018

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“…The cannabis C THC levels obtained indicate that the cannabis samples used cover a realistic range, based on national and international work [40][41][42][49][50][51][52][53]. It has often been noted in international studies that over time, there has been an increase in the C THC of cannabis.…”

Section: Discussionmentioning

confidence: 99%

Chemical and physical variations of cannabis smoke from a variety of cannabis samples in New Zealand

Sheehan

Hamnett

Beasley

et al. 2018

Forensic Sciences Research

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Studies have compared the chemical properties of tobacco smoke to those of cannabis smoke, with the objective of identifying the chemical attributes responsible for the mutagenicity and carcinogenicity of cannabis smoke. Comparative studies have included small sample sizes and produced conflicting results. The aim of this study was to assess the major chemical and physical variations of cannabis smoke across a range of cannabis samples of different potencies and origins, sourced from the illegal market in New Zealand. Twelve cannabis samples were studied ranging from 1.0% to 13.4% delta-9-tetrahydrocannabinol (D 9 THC) content. A smoking machine was used to smoke "joints" (cannabis cigarettes) and the chemical/physical properties of the smoke assessed. The chemical constituents of the smoke extracts were analysed by gas chromatography/mass spectrometry. A range of different chemical constituents (in addition to D 9 THC) were identified and their concentrations estimated. Terpenoids were identified as the major variable in cannabis smoke, showing a 40-fold range in total terpenoid content. Analysis of the total particulate matter showed that significantly different levels of particulate matter were produced between the different cannabis samples, ranging from 14.6 to 66.3 mg/g of cannabis smoked. The D 9 THC delivery efficiency during smoking was also investigated and produced consistent results showing a mean and median of 12.6% and 10.8%, respectively, of the theoretically available D 9 THC (ranging from 7.2% to 28.0%).

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“…The average THC content in confiscated cannabis in 1990 was around 3.7 percent for marijuana and 7.5 percent for sinsemilla, which is higher potency marijuana from a specially tended female plant. Compared to these numbers, the contents changed towards the more potent form, with averaging 9.6 percent for marijuana and 16 percent for sinsemilla [11]. Also newer forms of marijuana are available with higher contents of THC that contain THC-rich hash oil.…”

Section: Natural Formmentioning

confidence: 99%