RESULTS Although causality is unclear , heavy and dependent cannabis use is consistently associated with a high prevalence of comorbid psychiatric disorders and learning and memory impairments that seem to recover after a period of abstinence .
Evidence regarding other cognitive domains and neurological consequences including cerebrovascular events is limited and inconsistent .
Abstinence after treatment is only achieved in a minority of cases ; treatment targeted at reduction in use appears have some success .
Potential moderators of the impact of CUD on the brain include age of onset , heaviness of use , CUD severity , the ratio of ∆9-tetrahydrocannabinol to cannabidiol , and severity of comorbid disorders .
Current evidence of long-term effects of daily cannabis use and cannabis use disorder on brain-related outcomes is suggestive rather than conclusive but use is associated with psychiatric morbidity and with cognitive impairments that recover after a period of abstinence
AIMS To summarize and evaluate our knowledge of the relationship between heavy cannabis use , Cannabis Use Disorder ( CUD ) , and the brain .
A study investigating the acute dose— response effects of 13 mg and 17 mg Δ 9- tetrahydrocannabinol on cognitive—motor skills, subjective and autonomic measures in regular users of marijuana
Heavy use of marijuana is cl aim ed to damage critical skills related to short-term memory , visual scanning and attention . Motor skills and driving safety may be compromised by the acute effects of marijuana . The aim of this study was to investigate the acute effects of 13 mg and 17 mg Δ 9-tetrahydrocannabinol ( THC ) on skills important for coordinated movement and driving and on subjective and autonomic measures in regular users of marijuana . Fourteen regular users of marijuana were enrolled . Each subject was tested on two separate days . On each test day , subjects smoked two low-nicotine cigarettes , one with and the other without THC . Seventeen mg THC was included in the cigarette on one test day and 13 mg on the other day . The sequence of cigarette types was unknown to the subject . During smoking , heart rate and blood pressure were monitored , and the subjects performed a virtual reality maze task requiring attention and motor coordination , followed by 3 other cognitive tasks ( Wisconsin Card Sorting Test ( WCST ) , a “ gambling ” task and estimation of time and distance from an approaching car ) . After smoking a cigarette with 17 mg THC , regular marijuana users hit the walls more often on the virtual maze task than after smoking cigarettes without THC ; this effect was not seen in patients after they smoked cigarettes with 13 mg THC . Performance in the WCST was affected with 17 mg THC and to a lesser extent with the use of 13 mg THC . Decision making in the gambling task was affected after smoking cigarettes with 17 mg THC , but not with 13 m THC . Smoking cigarettes with 13 and 17 mg THC increased subjective ratings of pleasure and satisfaction , drug “ effect ” and drug “ high ” . These findings imply that smoking of 17 mg THC results in impairment of cognitive — motor skills that could be important for coordinated movemen and driving , whereas the lower dose of 13 mg THC appears to cause less impairment of such skills in regular users of marijuana
RESULTS Although causality is unclear , heavy and dependent cannabis use is consistently associated with a high prevalence of comorbid psychiatric disorders and learning and memory impairments that seem to recover after a period of abstinence .
Evidence regarding other cognitive domains and neurological consequences including cerebrovascular events is limited and inconsistent .
Abstinence after treatment is only achieved in a minority of cases ; treatment targeted at reduction in use appears have some success .
Potential moderators of the impact of CUD on the brain include age of onset , heaviness of use , CUD severity , the ratio of ∆9-tetrahydrocannabinol to cannabidiol , and severity of comorbid disorders .
Current evidence of long-term effects of daily cannabis use and cannabis use disorder on brain-related outcomes is suggestive rather than conclusive but use is associated with psychiatric morbidity and with cognitive impairments that recover after a period of abstinence
AIMS To summarize and evaluate our knowledge of the relationship between heavy cannabis use , Cannabis Use Disorder ( CUD ) , and the brain .