@article{ref1,
title="Cognitive and psychomotor effects in males after smoking a combination of tobacco and cannabis containing up to 69 mg delta-9-tetrahydrocannabinol (THC)",
journal="Psychopharmacology",
year="2009",
author="Hunault, Claudine and Mensinga, Tjeert and Böcker, Koen and Schipper, C. and Kruidenier, Maaike and Leenders, Marianne and Vries, Irma and Meulenbelt, Jan",
volume="204",
number="1",
pages="85-94",
abstract="RATIONALE:Delta(9)-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. TRIAL REGISTRATION:ClinicalTrials.gov NCT00225407.<p /><p>Language: en</p>",
language="en",
issn="0033-3158",
doi="10.1007/s00213-008-1440-0",
url="http://dx.doi.org/10.1007/s00213-008-1440-0"
}