Hostname: page-component-586b7cd67f-2plfb Total loading time: 0 Render date: 2024-11-27T20:34:22.687Z Has data issue: false hasContentIssue false
  • English
  • Français

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

Published online by Cambridge University Press:  31 January 2018

Tom P. Freeman ,
Peggy van der Pol ,
Wil Kuijpers ,
Jeroen Wisselink ,
Ravi K. Das ,
Sander Rigter ,
Margriet van Laar ,
Paul Griffiths ,
Wendy Swift  and
Raymond Niesink
...Show all authors
Tom P. Freeman*
Affiliation:
National Addiction Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK Clinical Psychopharmacology Unit, University College London, London, UK
Peggy van der Pol
Affiliation:
Trimbos Institute, Netherlands Institute of Mental Health and Addiction, Utrecht, the Netherlands
Wil Kuijpers
Affiliation:
Stichting Informatievoorziening Zorg, National Alcohol and Drugs Information System, Houten, the Netherlands
Jeroen Wisselink
Affiliation:
Stichting Informatievoorziening Zorg, National Alcohol and Drugs Information System, Houten, the Netherlands
Ravi K. Das
Affiliation:
Clinical Psychopharmacology Unit, University College London, London, UK
Sander Rigter
Affiliation:
Trimbos Institute, Netherlands Institute of Mental Health and Addiction, Utrecht, the Netherlands
Margriet van Laar
Affiliation:
Trimbos Institute, Netherlands Institute of Mental Health and Addiction, Utrecht, the Netherlands
Paul Griffiths
Affiliation:
European Monitoring Centre for Drugs and Drug Addiction, Portugal
Wendy Swift
Affiliation:
National Drug and Alcohol Research Centre, UNSW Australia, Sydney, NSW, Australia
Raymond Niesink
Affiliation:
Trimbos Institute, Netherlands Institute of Mental Health and Addiction, Utrecht, the Netherlands
Michael T. Lynskey
Affiliation:
National Addiction Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
*
Author for correspondence: Tom P. Freeman, E-mail: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

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 (2000–2015). 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.

Results

THC increased from a mean (95% CI) of 8.62 (7.97–9.27) to 20.38 (19.09–21.67) from 2000 to 2004 and then decreased to 15.31 (14.24–16.38) in 2015. First-time cannabis admissions (per 100 000 inhabitants) rose from 7.08 to 26.36 from 2000 to 2010, and then decreased to 19.82 in 2015. THC was positively associated with treatment entry at lags of 0–9 years, with the strongest association at 5 years, b = 0.370 (0.317–0.424), p < 0.0001. 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.

Keywords

addictionmental healthpsychosisdrug treatmentcannabisδ-9-tetrahydrocannabinolpotency
Type
Original Articles
Information
Psychological Medicine , Volume 48 , Issue 14 , October 2018 , pp. 2346 - 2352
Copyright
Copyright © Cambridge University Press 2018 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Behrendt, S, Wittchen, H-U, Höfler, M, Lieb, R and Beesdo, K (2009) Transitions from first substance use to substance use disorders in adolescence: is early onset associated with a rapid escalation? Drug and Alcohol Dependence 99, 68–78.Google Scholar
Brunt, TM, van Laar, M, Niesink, RJ and van den Brink, W (2010) The relationship of quality and price of the psychostimulants cocaine and amphetamine with health care outcomes. Drug and Alcohol Dependence 111, 21–29.Google Scholar
Cascini, F, Aiello, C and Di Tanna, G (2012) Increasing delta-9-tetrahydrocannabinol (Δ−9-THC) content in herbal cannabis over time: systematic review and meta-analysis. Current Drug Abuse Reviews 5, 32–40.Google Scholar
Chan, GC, Hall, W, Freeman, TP, Ferris, J, Kelly, AB and Winstock, A (2017) User characteristics and effect profile of Butane Hash Oil: an extremely high-potency cannabis concentrate. Drug and Alcohol Dependence 178, 32–38.Google Scholar
Colizzi, M and Bhattacharyya, S (2017) Does cannabis composition matter? Differential effects of delta-9-tetrahydrocannabinol and cannabidiol on human cognition. Current Addiction Reports 4, 62–74.Google Scholar
Courtney, KE, Mejia, MH and Jacobus, J (2017) Longitudinal studies on the etiology of cannabis use disorder: a review. Current Addiction Reports 4, 43–52.Google Scholar
Curran, HV, Freeman, TP, Mokrysz, C, Lewis, DA, Morgan, CJ and Parsons, LH (2016) Keep off the grass? Cannabis, cognition and addiction. Nature Reviews Neuroscience 17, 293–306.Google Scholar
Di Forti, M, Marconi, A, Carra, E, Fraietta, S, Trotta, A, Bonomo, M et al. (2015) Proportion of patients in south London with first-episode psychosis attributable to use of high potency cannabis: a case-control study. The Lancet Psychiatry 2, 233–238.Google Scholar
D'Souza, DC, Ranganathan, M, Braley, G, Gueorguieva, R, Zimolo, Z, Cooper, T et al. (2008) Blunted psychotomimetic and amnestic effects of Δ−9-tetrahydrocannabinol in frequent users of cannabis. Neuropsychopharmacology 33, 2505–2516.Google Scholar
ElSohly, MA, Mehmedic, Z, Foster, S, Gon, C, Chandra, S and Church, JC (2016) Changes in cannabis potency over the last 2 decades (1995–2014): analysis of current data in the United States. Biological Psychiatry 79, 613–619.Google Scholar
EMCDDA (2014) Report to the EMCDDA by the Reitox National Focal Point. The Netherlands Drug Situation 2014. Luxembourg: Publications Office of the European Union.Google Scholar
EMCDDA (2016) European Drug Report: Trends and Developments. Luxembourg: Publications Office of the European Union.Google Scholar
Englund, A, Freeman, TP, Murray, RM and McGuire, P (2017) Can we make cannabis safer? The Lancet Psychiatry 4, 643–648.Google Scholar
Freeman, T and Winstock, A (2015) Examining the profile of high-potency cannabis and its association with severity of cannabis dependence. Psychological Medicine 45, 3181–3189.Google Scholar
Freeman, TP, Morgan, CJA, Hindocha, C, Schafer, GL, Das, RK and Curran, HV (2014) Just say ‘know’: how do cannabinoid concentrations influence users’ estimates of cannabis potency and the amount they roll in joints? Addiction 109, 1686–1694.Google Scholar
Freeman, TP and Swift, W (2016) Cannabis potency: the need for global monitoring. Addiction 111, 376–377.Google Scholar
McLaren, J, Swift, W, Dillon, P and Allsop, S (2008) Cannabis potency and contamination: a review of the literature. Addiction 103, 1100–1109.Google Scholar
Meier, MH (2017) Associations between butane hash oil use and cannabis-related problems. Drug and Alcohol Dependence 179, 25–31.Google Scholar
Mokrysz, C, Freeman, T, Korkki, S, Griffiths, K and Curran, H (2016) Are adolescents more vulnerable to the harmful effects of cannabis than adults? A placebo-controlled study in human males. Translational Psychiatry 6, e961.Google Scholar
Monaghan, M, Hamilton, I, Lloyd, C and Paton, K (2016) Cannabis matters? Treatment responses to increasing cannabis presentations in addiction services in England. Drugs: Education, Prevention and Policy 23, 54–61.Google Scholar
Monshouwer, K, Van Laar, M and Vollebergh, WA (2011) Buying cannabis in ‘coffee shops’. Drug and Alcohol Review 30, 148–156.Google Scholar
Montanari, L, Guarita, B, Mounteney, J, Zipfel, N and Simon, R (2017) Cannabis use among people entering drug treatment in Europe: a growing phenomenon? European Addiction Research 23, 113.Google Scholar
NDTMS (2014) Adult Drug Statistics from the National Drug Treatment Monitoring System (NDTMS).Google Scholar
Nguyen, H and Reuter, P (2012) How risky is marijuana possession? Considering the role of age, race, and gender. Crime & Delinquency 58, 879–910.Google Scholar
Niesink, RJ, Rigter, S, Koeter, MW and Brunt, TM (2015) Potency trends of Δ9-tetrahydrocannabinol, cannabidiol and cannabinol in cannabis in the Netherlands: 2005–15. Addiction 110, 1941–1950.Google Scholar
Pijlman, F, Rigter, S, Hoek, J, Goldschmidt, H and Niesink, R (2005) Strong increase in total delta-THC in cannabis preparations sold in Dutch coffee shops. Addiction Biology 10, 171–180.Google Scholar
Potter, DJ, Clark, P and Brown, MB (2008) Potency of Δ9–THC and other cannabinoids in cannabis in England in 2005: implications for psychoactivity and pharmacology. Journal of Forensic Sciences 53, 90–94.Google Scholar
Schoeler, T, Petros, N, Di Forti, M, Klamerus, E, Foglia, E, Ajnakina, O et al. (2016) Effects of continuation, frequency, and type of cannabis use on relapse in the first 2 years after onset of psychosis: an observational study. The Lancet Psychiatry 3, 947–953.Google Scholar
Schubart, CD, Sommer, IE, van Gastel, WA, Goetgebuer, RL, Kahn, RS and Boks, MP (2011) Cannabis with high cannabidiol content is associated with fewer psychotic experiences. Schizophrenia Research 130, 216–221.Google Scholar
Sevigny, EL (2013) Is today's marijuana more potent simply because it's fresher? Drug Testing and Analysis 5, 62–67.Google Scholar
Silins, E, Horwood, LJ, Patton, GC, Fergusson, DM, Olsson, CA, Hutchinson, DM et al. (2014) Young adult sequelae of adolescent cannabis use: an integrative analysis. The Lancet Psychiatry 1, 286–293.Google Scholar
Smart, R, Caulkins, JP, Kilmer, B, Davenport, S and Midgette, G (2017) Variation in cannabis potency and prices in a newly-legal market: evidence from 30 million cannabis sales in Washington state. Addiction 112, 2167–2177.Google Scholar
Swift, W, Wong, A, Li, KM, Arnold, JC and McGregor, IS (2013) Analysis of cannabis seizures in NSW, Australia: cannabis potency and cannabinoid profile. PLoS ONE 8, e70052.Google Scholar
UNODC (2016) United Nations Office on Drugs and Crime, World Drug Report 2016 (United Nations publication, Sales No. E.16.XI.7).Google Scholar
van der Pol, P, Liebregts, N, Brunt, T, Amsterdam, J, Graaf, R, Korf, DJ et al. (2014) Cross-sectional and prospective relation of cannabis potency, dosing and smoking behaviour with cannabis dependence: an ecological study. Addiction 109, 1101–1109.Google Scholar
van der Pol, P, Liebregts, N, de Graaf, R, Korf, DJ, van den Brink, W and van Laar, M (2013a) Predicting the transition from frequent cannabis use to cannabis dependence: a three-year prospective study. Drug and Alcohol Dependence 133, 352–359.Google Scholar
van der Pol, P, Liebregts, N, Graaf, R, Have, M, Korf, DJ, Brink, W et al. (2013b) Mental health differences between frequent cannabis users with and without dependence and the general population. Addiction 108, 1459–1469.Google Scholar
Van Laar, M, Van Der Pol, P and Niesink, R (2016) Limitations to the Dutch cannabis toleration policy: assumptions underlying the reclassification of cannabis above 15% THC. International Journal of Drug Policy 34, 58–64.Google Scholar
Wisselink, DJ, Kuijpers, WGT and Mol, A (2016) Key Figures Addiction Care 2015. Houten: Stichting Informatie Voorziening Zorg.Google Scholar
Wouters, M and Korf, DJ (2009) Access to licensed cannabis supply and the separation of markets policy in the Netherlands. Journal of Drug Issues 39, 627–651.Google Scholar
Supplementary material: PDF

Freeman et al. supplementary material

Figures S1-S7 and Table S1

Download Freeman et al. supplementary material(PDF)
PDF 348.7 KB