Differential impairments of selective attention due to frequency and duration of cannabis use.
The evidence for long-term cognitive impairments associated with chronic use of cannabis has been inconclusive. We report the results of a brain event-related potential (ERP) study of selective attention in long-term cannabis users in the unintoxicated state. Two ERP measures known to reflect distinct components of attention were found to be affected differentially by duration and frequency of cannabis use. The ability to focus attention and filter out irrelevant information, measured by frontal processing negativity to irrelevant stimuli, was impaired progressively with the number of years of use but was unrelated to frequency of use. The speed of information processing, measured by the latency of parietal P300, was delayed significantly with increasing frequency of use but was unaffected by duration of use. The results suggest that a chronic buildup of cannabinoids produces both short- and long-term cognitive impairments.
Solowij
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National Drug and Alcohol Research Centre, University of New South Wales, Sydney, Australia.
Michie
P T
PT
Fox
A M
AM
D000293:Adolescent; D000328:Adult; D000428:Alcohol Drinking / Q000009:adverse effects; D001143:Arousal / Q000187:drug effects*; D001288:Attention / Q000187:drug effects*; D003265:Contingent Negative Variation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004569:Electroencephalography / Q000187:drug effects*; D005072:Evoked Potentials, Auditory / Q000187:drug effects*; D005260:Female; D005625:Frontal Lobe / Q000187:drug effects; D007839:Functional Laterality / Q000187:drug effects; D006801:Humans; D008297:Male; D002189:Marijuana Abuse / Q000523:psychology*; D008385:Marijuana Smoking / Q000009:adverse effects* / Q000523:psychology; D010897:Pitch Discrimination / Q000187:drug effects; D011930:Reaction Time / Q000187:drug effects