DIFFERENTIAL IMPAIRMENTS OF SELECTIVE ATTENTION DUE TO FREQUENCY AND DURATION OF CANNABIS USE

The evidence for long-term cognitive impairments associated with chron ic use of cannabis has been inconclusive, We report the results of a b rain event-related potential (ERP) study of selective attention in lon g-term cannabis users in the unintoxicated state. Two ERP measures kno wn to reflect distinct components of attention were found to be affect ed differentially by duration and frequency of cannabis use, The abili ty refocus attention and filter out irrelevant information, measured b y frontal processing negativity to irrelevant stimuli, was impaired pr ogressively with the number of years of use but was unrelated to frequ ency of use. The speed of information processing, measured by the late ncy of parietal P300, was delayed significantly with increasing freque ncy of use but was unaffected by duration of use, The results suggest that a chronic buildup of cannabinoids produces both short- and long-t erm cognitive impairments.