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 .
Cannabidiol Attenuates the Appetitive Effects of Δ9-Tetrahydrocannabinol in Humans Smoking Their Chosen Cannabis
Worldwide cannabis dependence is increasing , as is the concentration of Δ9-tetrahydrocannabinol ( THC ) in street cannabis . At the same time , the concentration of the second most abundant cannabinoid in street cannabis ,  cannabidiol  ( CBD ) , is decreasing . These two cannabinoids have opposing effects both pharmacologically and behaviorally when administered in the laboratory . No research has yet examined how the ratio of these constituents impacts on the appetitive/reinforcing effects of cannabis in humans . A total of 94 cannabis users were tested 7 days apart , once while non-intoxicated and once while acutely under the influence of their own chosen smoked cannabis on dependence-related measures . Using an unprecedented methodology , a sample of cannabis ( as well as saliva ) was collected from each user and analyzed for levels of cannabinoids . On the basis of CBD : THC ratios in the cannabis , individuals from the top and bottom tertiles were directly compared on indices of the reinforcing effects of drugs , explicit liking , and implicit attentional bias to drug stimuli . When intoxicated , smokers of high CBD : THC strains showed reduced attentional bias to drug and food stimuli compared with smokers of low CBD : THC . Those smoking higher CBD : THC strains also showed lower self-rated liking of cannabis stimuli on both test days . Our findings suggest that CBD has potential as a treatment for cannabis dependence . The acute modulation of the incentive salience of drug cues by CBD may possibly generalize to a treatment for other addictive disorders
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 .