Psychopharmacology

, Volume 204, Issue 1, pp 85–94

Cognitive and psychomotor effects in males after smoking a combination of tobacco and cannabis containing up to 69 mg delta-9-tetrahydrocannabinol (THC)

  • Claudine C. Hunault
  • Tjeert T. Mensinga
  • Koen B. E. Böcker
  • C. Maarten A. Schipper
  • Maaike Kruidenier
  • Marianne E. C. Leenders
  • Irma de Vries
  • Jan Meulenbelt
Original Investigation

DOI: 10.1007/s00213-008-1440-0

Cite this article as:
Hunault, C.C., Mensinga, T.T., Böcker, K.B.E. et al. Psychopharmacology (2009) 204: 85. doi:10.1007/s00213-008-1440-0

Abstract

Rationale

Δ9-Tetrahydrocannabinol (THC) is the main active constituent of cannabis. In recent years, the average THC content of some cannabis cigarettes has increased up to approximately 60 mg per cigarette (20% THC cigarettes). Acute cognitive and psychomotor effects of THC among recreational users after smoking cannabis cigarettes containing such high doses are unknown.

Objectives

The objective of this study was to study the dose–effect relationship between the THC dose contained in cannabis cigarettes and cognitive and psychomotor effects for THC doses up to 69.4 mg (23%).

Materials and methods

This double-blind, placebo-controlled, randomised, four-way cross-over study included 24 non-daily male cannabis users (two to nine cannabis cigarettes per month). Participants smoked four cannabis cigarettes containing 0, 29.3, 49.1 and 69.4 mg THC on four exposure days.

Results

The THC dose in smoked cannabis was linearly associated with a slower response time in all tasks (simple reaction time, visuo-spatial selective attention, sustained attention, divided attention and short-term memory tasks) and motor control impairment in the motor control task. The number of errors increased significantly with increasing doses in the short-term memory and the sustained attention tasks. Some participants showed no impairment in motor control even at THC serum concentrations higher than 40 ng/mL. High feeling and drowsiness differed significantly between treatments.

Conclusions

Response time slowed down and motor control worsened, both linearly, with increasing THC doses. Consequently, cannabis with high THC concentrations may be a concern for public health and safety if cannabis smokers are unable to titrate to a high feeling corresponding to a desired plasma THC level.

Keywords

Cannabis THC Cognitive impairment Psychomotor impairment Acute High dose Cognitive functions 

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • Claudine C. Hunault
    • 1
    • 8
  • Tjeert T. Mensinga
    • 1
    • 2
  • Koen B. E. Böcker
    • 3
  • C. Maarten A. Schipper
    • 4
  • Maaike Kruidenier
    • 1
  • Marianne E. C. Leenders
    • 1
    • 5
  • Irma de Vries
    • 1
  • Jan Meulenbelt
    • 1
    • 6
    • 7
  1. 1.National Poisons Information CenterNational Institute for Public Health and the EnvironmentBilthovenThe Netherlands
  2. 2.Clinic for Treatment of Drug Addiction in NorthernGroningenThe Netherlands
  3. 3.Department of Psychopharmacology, Utrecht Institute of Pharmaceutical Studies, Rudolf Magnus Institute of Neuroscience & Helmholz InstituteUtrecht UniversityUtrechtThe Netherlands
  4. 4.Expertise Centre for Methodology and Information ServicesNational Institute for Public Health and the EnvironmentBilthovenThe Netherlands
  5. 5.Division of Perioperative and Emergency CareUniversity Medical Center UtrechtUtrechtThe Netherlands
  6. 6.Division of Intensive Care CenterUniversity Medical Center UtrechtUtrechtThe Netherlands
  7. 7.Institute for Risk Assessment SciencesUniversity UtrechtUtrechtThe Netherlands
  8. 8.National Institute for Public Health and the EnvironmentBilthovenThe Netherlands

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