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 .
Cue-induced striatal activity in frequent cannabis users independently predicts cannabis problem severity three years later
Cannabis is the most frequently used illicit drug worldwide , but little is known about the mechanisms underlying continued cannabis use . Cue-reactivity ( the physical , psychological , behavioural and neural reaction to substance-related cues ) might be related to continued cannabis use . In this 3-year prospect i ve neuroimaging study we investigated whether cannabis cue-induced brain activity predicted continued cannabis use and associated problem severity 3 years later . In addition , baseline brain activations were compared between dependent and non-dependent cannabis users at follow-up . Analyses were focussed on brain areas known to be important in cannabis cue-reactivity : anterior cingulate cortex , orbitofrontal cortex , ventral tegmental area , amygdala and striatum . At baseline , 31 treatment-naive frequent cannabis users performed a  cue-reactivity functional magnetic resonance imaging task . Of these participants , 23 completed the 3-year follow-up . None of the cue-induced region of interest activations predicted the amount of cannabis use at follow-up . However , cue-induced activation in the left striatum ( putamen ) significantly and independently predicted problem severity at follow-up ( p < 0.001 ) as assessed with the Cannabis Use Disorder Identification Test . Also , clinical ly dependent cannabis users at follow-up showed higher baseline activation at trend level in the left striatum compared with non-dependent users . This indicates that neural cue-reactivity in the dorsal striatum is an independent predictor of cannabis use-related problems . Given the relatively small sample size , these results are preliminary and should be replicated in larger sample s of cannabis users
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 .