Tags

Type your tag names separated by a space and hit enter

Cognition and motor control as a function of Delta9-THC concentration in serum and oral fluid: limits of impairment.
Drug Alcohol Depend. 2006 Nov 08; 85(2):114-22.DA

Abstract

Cannabis use has been associated with increased risk of becoming involved in traffic accidents; however, the relation between THC concentration and driver impairment is relatively obscure. The present study was designed to define performance impairment as a function of THC in serum and oral fluid in order to provide a scientific framework to the development of per se limits for driving under the influence of cannabis. Twenty recreational users of cannabis participated in a double-blind, placebo-controlled, three-way cross-over study. Subjects were administered single doses of 0, 250 and 500 microg/kg THC by smoking. Performance tests measuring skills related to driving were conducted at regular intervals between 15 min and 6h post smoking and included measures of perceptual-motor control (Critical tracking task), motor impulsivity (Stop signal task) and cognitive function (Tower of London). Blood and oral fluid were collected throughout testing. Results showed a strong and linear relation between THC in serum and oral fluid. Linear relations between magnitude of performance impairment and THC in oral fluid and serum, however, were low. A more promising way to define threshold levels of impairment was found by comparing the proportion of observations showing impairment or no impairment as a function of THC concentration. The proportion of observations showing impairment progressively increased as a function of serum THC in every task. Binomial tests showed an initial and significant shift toward impairment in the Critical tracking task for serum THC concentrations between 2 and 5 ng/ml. At concentrations between 5 and 10 ng/ml approximately 75-90% of the observations were indicative of significant impairment in every performance test. At THC concentrations >30 ng/ml the proportion of observations indicative of significant impairment increased to a full 100% in every performance tests. It is concluded that serum THC concentrations between 2 and 5 ng/ml establish the lower and upper range of a THC limit for impairment.

Authors+Show Affiliations

Experimental Psychopharmacology Unit, Department of Neurocognition, Faculty of Psychology, Maastricht University, 6200 MD Maastricht, The Netherlands. j.ramaekers@psychology.unimaas.nlNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Randomized Controlled Trial
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

16723194

Citation

Ramaekers, J G., et al. "Cognition and Motor Control as a Function of Delta9-THC Concentration in Serum and Oral Fluid: Limits of Impairment." Drug and Alcohol Dependence, vol. 85, no. 2, 2006, pp. 114-22.
Ramaekers JG, Moeller MR, van Ruitenbeek P, et al. Cognition and motor control as a function of Delta9-THC concentration in serum and oral fluid: limits of impairment. Drug Alcohol Depend. 2006;85(2):114-22.
Ramaekers, J. G., Moeller, M. R., van Ruitenbeek, P., Theunissen, E. L., Schneider, E., & Kauert, G. (2006). Cognition and motor control as a function of Delta9-THC concentration in serum and oral fluid: limits of impairment. Drug and Alcohol Dependence, 85(2), 114-22.
Ramaekers JG, et al. Cognition and Motor Control as a Function of Delta9-THC Concentration in Serum and Oral Fluid: Limits of Impairment. Drug Alcohol Depend. 2006 Nov 8;85(2):114-22. PubMed PMID: 16723194.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Cognition and motor control as a function of Delta9-THC concentration in serum and oral fluid: limits of impairment. AU - Ramaekers,J G, AU - Moeller,M R, AU - van Ruitenbeek,P, AU - Theunissen,E L, AU - Schneider,E, AU - Kauert,G, Y1 - 2006/05/24/ PY - 2005/12/14/received PY - 2006/03/22/revised PY - 2006/03/23/accepted PY - 2006/5/26/pubmed PY - 2007/2/23/medline PY - 2006/5/26/entrez SP - 114 EP - 22 JF - Drug and alcohol dependence JO - Drug Alcohol Depend VL - 85 IS - 2 N2 - Cannabis use has been associated with increased risk of becoming involved in traffic accidents; however, the relation between THC concentration and driver impairment is relatively obscure. The present study was designed to define performance impairment as a function of THC in serum and oral fluid in order to provide a scientific framework to the development of per se limits for driving under the influence of cannabis. Twenty recreational users of cannabis participated in a double-blind, placebo-controlled, three-way cross-over study. Subjects were administered single doses of 0, 250 and 500 microg/kg THC by smoking. Performance tests measuring skills related to driving were conducted at regular intervals between 15 min and 6h post smoking and included measures of perceptual-motor control (Critical tracking task), motor impulsivity (Stop signal task) and cognitive function (Tower of London). Blood and oral fluid were collected throughout testing. Results showed a strong and linear relation between THC in serum and oral fluid. Linear relations between magnitude of performance impairment and THC in oral fluid and serum, however, were low. A more promising way to define threshold levels of impairment was found by comparing the proportion of observations showing impairment or no impairment as a function of THC concentration. The proportion of observations showing impairment progressively increased as a function of serum THC in every task. Binomial tests showed an initial and significant shift toward impairment in the Critical tracking task for serum THC concentrations between 2 and 5 ng/ml. At concentrations between 5 and 10 ng/ml approximately 75-90% of the observations were indicative of significant impairment in every performance test. At THC concentrations >30 ng/ml the proportion of observations indicative of significant impairment increased to a full 100% in every performance tests. It is concluded that serum THC concentrations between 2 and 5 ng/ml establish the lower and upper range of a THC limit for impairment. SN - 0376-8716 UR - https://www.unboundmedicine.com/medline/citation/16723194/Cognition_and_motor_control_as_a_function_of_Delta9_THC_concentration_in_serum_and_oral_fluid:_limits_of_impairment_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0376-8716(06)00137-2 DB - PRIME DP - Unbound Medicine ER -