Cannabis with high δ9-THC contents affects perception and visual selective attention acutely: an event-related potential study.
OBJECTIVE
Cannabis intake has been reported to affect cognitive functions such as selective attention. This study addressed the effects of exposure to cannabis with up to 69.4mg Delta(9)-tetrahydrocannabinol (THC) on Event-Related Potentials (ERPs) recorded during a visual selective attention task.


METHODS
Twenty-four participants smoked cannabis cigarettes with four doses of THC on four test days in a randomized, double blind, placebo-controlled, crossover study. Two hours after THC exposure the participants performed a visual selective attention task and concomitant ERPs were recorded.


RESULTS
Accuracy decreased linearly and reaction times increased linearly with THC dose. However, performance measures and most of the ERP components related specifically to selective attention did not show significant dose effects. Only in relatively light cannabis users the Occipital Selection Negativity decreased linearly with dose. Furthermore, ERP components reflecting perceptual processing, as well as the P300 component, decreased in amplitude after THC exposure. Only the former effect showed a linear dose-response relation.


CONCLUSIONS
The decrements in performance and ERP amplitudes induced by exposure to cannabis with high THC content resulted from a non-selective decrease in attentional or processing resources.


CONCLUSIONS
Performance requiring attentional resources, such as vehicle control, may be compromised several hours after smoking cannabis cigarettes containing high doses of THC, as presently available in Europe and Northern America.
Böcker
K B E
KB
Dept. Psychopharmacology, Utrecht Institute of Pharmaceutical Studies & Rudolf Magnus Institute of Neuroscience, Utrecht University, The Netherlands. K.B.E.Bocker@uu.nl
Gerritsen
J
J
Hunault
C C
CC
Kruidenier
M
M
Mensinga
Tj T
TT
Kenemans
J L
JL
D000293:Adolescent; D000328:Adult; D001288:Attention / Q000187:drug effects* / Q000502:physiology; D002188:Cannabis / Q000737:chemistry; D018592:Cross-Over Studies; D004311:Double-Blind Method; D013759:Dronabinol / Q000008:administration & dosage / Q000737:chemistry*; D005074:Evoked Potentials, Visual / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D008297:Male; D008385:Marijuana Smoking / Q000009:adverse effects* / Q000503:physiopathology; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance / Q000187:drug effects* / Q000502:physiology; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D013997:Time Factors; D014796:Visual Perception / Q000187:drug effects* / Q000502:physiology; D055815:Young Adult
D013759:Dronabinol