title: Cannabis and tolerance: acute drug impairment as a function of cannabis use history.
abstract: Cannabis use history as predictor of neurocognitive response to cannabis intoxication remains subject to scientific and policy debates. The present study assessed the influence of cannabis on neurocognition in cannabis users whose cannabis use history ranged from infrequent to daily use. Drug users (N = 122) received acute doses of cannabis (300 μg/kg THC), cocaine HCl (300 mg) and placebo. Cocaine served as active control for demonstrating neurocognitive test sensitivity. Executive function, impulse control, attention, psychomotor function and subjective intoxication were significantly worse after cannabis administration relative to placebo. Cocaine improved psychomotor function and attention, impaired impulse control and increased feelings of intoxication. Acute effects of cannabis and cocaine on neurocognitive performance were similar across cannabis users irrespective of their cannabis use history. Absence of tolerance implies that that frequent cannabis use and intoxication can be expected to interfere with neurocognitive performance in many daily environments such as school, work or traffic.
authors.affiliation: Dept Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands.
authors.forename: J G
authors.initials: JG
authors.lastname: Ramaekers
authors.affiliation: Dept Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands.
authors.forename: J H
authors.initials: JH
authors.lastname: van Wel
authors.affiliation: Dept of Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud university medical center, Nijmegen, The Netherlands.
authors.forename: D B
authors.initials: DB
authors.lastname: Spronk
authors.affiliation: Dept of Forensic Toxicology, Institute of Legal Medicine, Goethe University of Frankfurt, Frankfurt, Germany.
authors.forename: S W
authors.initials: SW
authors.lastname: Toennes
authors.affiliation: Dept Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands.
authors.forename: K P C
authors.initials: KP
authors.lastname: Kuypers
authors.affiliation: Dept Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands.
authors.forename: E L
authors.initials: EL
authors.lastname: Theunissen
authors.affiliation: Dept of Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud university medical center, Nijmegen, The Netherlands.|The Netherlands Forensic Psychiatric Centre Pompestichting, Nijmegen, The Netherlands.
authors.forename: R J
authors.initials: RJ
authors.lastname: Verkes
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D001288:Attention / Q000187:drug effects; D003042:Cocaine / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology; D019970:Cocaine-Related Disorders / Q000523:psychology; D003071:Cognition / Q000187:drug effects*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D013759:Dronabinol / Q000009:adverse effects* / Q000493:pharmacokinetics; D004361:Drug Tolerance; D055030:Drug Users / Q000523:psychology*; D056344:Executive Function / Q000187:drug effects; D005260:Female; D006184:Habits; D006801:Humans; D007175:Impulsive Behavior / Q000187:drug effects; D008297:Male; D002189:Marijuana Abuse / Q000523:psychology; D000073216:Mental Status and Dementia Tests; D009426:Netherlands; D011597:Psychomotor Performance / Q000187:drug effects*; D055815:Young Adult
chemical_list: D013759:Dronabinol; D003042:Cocaine