Cannabis use disorders in schizophrenia: Effects on cognition and symptoms Cannabis use and cannabis use disorders and their relationship to mental disorders: a 10-year prospective-longitudinal community study in adolescents. Adolescent cannabis use, change in neurocognitive function, and high-school graduation: A longitudinal study from early adolescence to young adulthood. The relevance of age at first alcohol and nicotine use for initiation of cannabis use and progression to cannabis use disorders. Cannabis abuse and the course of recent onset schizophrenic disorders The impact of substance use on brain structure in people at high risk of developing schizophrenia. Spatial working memory in heavy cannabis users: a functional magnetic resonance imaging study Cannabis Abstinence During Treatment and One-Year Follow-Up: Relationship to Neural Activity in Men Subjective Cannabis Effects as Part of a Developing Disorder in Adolescents and Emerging Adults Cue-induced striatal activity in frequent cannabis users independently predicts cannabis problem severity three years later Persistent cannabis users show neuropsychological decline from childhood to midlife Abnormal brain activity in prefrontal brain regions in abstinent marijuana users Age‐varying effects of cannabis use frequency and disorder on symptoms of psychosis, depression and anxiety in adolescents and adults Cognitive and Mental Health Predictors of Withdrawal Severity During an Active Attempt to Cut Down Cannabis Use A randomized placebo-controlled trial of N-acetylcysteine for cannabis use disorder in adults. Real-world memory and executive processes in cannabis users and non-users Cognitive Functioning of Adolescent and Young Adult Cannabis Users in the Philadelphia Neurodevelopmental Cohort
OBJECTIVE Despite the controversy surrounding the possible causal link between cannabis use and the onset of schizophrenia ( SZ ) , data seeking to eluci date the effect of cannabis use disorders ( CUDs ) on the clinical presentation of SZ have produced mixed results . Although several studies have suggested that CUD in patients with SZ may be associated with variation in cognitive function , clinical presentation and course of illness , the effects have been inconsistent . METHODS We retrospectively ascertained a large cohort ( N=455 ) of SZ patients with either no history of a CUD ( CUD- ; N=280 ) or a history of CUD ( CUD+ ; N=175 ) . The groups were initially compared on key demographic variables including sex , race , age , age at onset of SZ , parental socioeconomic status , premorbid IQ , education level and global assessment of functioning . Covarying for any observed differences in demographic variables , we then compared groups on lifetime measures of psychotic symptoms as well as a brief battery of neurocognitive tests . RESULTS Compared to the CUD- group the CUD+ group demonstrated significantly better performance on measures of processing speed ( Trail Making Tests A and B ) , verbal fluency ( animal naming ) and verbal learning and memory ( California Verbal Learning Test ) . Moreover , the CUD+ group had better GAF scores than the CUD group . CONCLUSIONS Collectively , these findings suggest that SZ patients with comorbid CUD may represent a higher functioning subgroup of SZ . Future prospect i ve studies are needed to eluci date the nature of this relationship BACKGROUND Whereas the role of externalizing disorders is relatively well established in predicting the onset of cannabis use ( CU ) or cannabis use disorder ( CUD ) , the status of anxiety and mood disorders in predicting CU and CUD remains controversial . OBJECTIVE ( 1 ) To examine cross-sectional and prospect i ve associations of CU and CUD with a range of mental disorders and whether anxiety and mood disorders are associated with CU/CUD after adjusting for externalizing disorders . METHODS N=1395 community subjects aged 14 - 17 at baseline were followed-up at three waves prospect ively over 10 years . Substance use , substance disorders and mental disorders were assessed using the DSM-IV/M-CIDI . RESULTS ( 1 ) The baseline prevalence rates where 19.3 % at t(0 ) for CU and 2.6 % for CUD . Cumulative incidence rates at t(3 ) were 54.3 % for CU and 13.7 % for CUD . ( 2 ) In cross-sectional and prospect i ve analyses other substance use disorders , mood and anxiety disorders were associated with CU and CUD . ( 3 ) Associations of panic-anxiety with CU and of depressive and bipolar disorders with CU and CUD were significant after controlling for externalizing disorders . CONCLUSION A range of psychopathological conditions , including depressive , bipolar and less consistently anxiety disorders as well as the degree of their comorbidity are significantly associated with incident CU and progression to CUD , even when controlling for externalising disorders . A better underst and ing of this complex interplay may result in better aetiological models and intervention strategies The main objective of this prospect i ve longitudinal study was to investigate bidirectional associations between adolescent cannabis use ( CU ) and  neurocognitive performance in a community sample of 294 young men from ages 13 to 20 years . The results showed that in early adolescence , and prior to initiation to CU , poor short-term and working memory , but high verbal IQ , were associated with earlier age of onset of CU . In turn , age of CU onset and CU frequency across adolescence were associated with ( a ) specific neurocognitive decline in verbal IQ and executive function tasks tapping trial and error learning and reward processing by early adulthood and ( b ) lower rates of high-school graduation . The association between CU onset and change in neurocognitive function , however , was found to be accounted for by CU frequency . Whereas the link between CU frequency across adolescence and change in verbal IQ was explained ( mediated ) by high school graduation , the link between CU frequency and tasks tapping trial and error learning were independent from high school graduation , concurrent cannabis and other substance use , adolescent alcohol use , and externalizing behaviors . Findings support prevention efforts aim ed at delaying onset and reducing frequency of CU BACKGROUND A younger age at onset of use of a specific substance is a well-documented risk-factor for a substance use disorder ( SUD ) related to that specific substance . However , the cross-substance relationship between a younger age at onset of alcohol use ( AU ) and nicotine use ( NU ) and the risk of cannabis use disorders ( CUD ) in adolescence and early adulthood remains unclear . AIMS To identify the sequence of and latency between initial AU/NU and initial cannabis use ( CU ) . To investigate whether younger age at AU- and NU-onset is associated with any and earlier CU-onset and a higher risk of transition from first CU to CUD , taking into account externalizing disorders ( ED ) and parental substance use disorders as putative influential factors . METHODS Prospect ive-longitudinal community study with N=3021 subjects ( baseline age 14 - 24 ) and up to four assessment waves over up to ten years with additional direct parental and family history information .  Substance use and CUD were assessed with the DSM-IV/M-CIDI . RESULTS Most subjects with CU reported AU ( 99 % ) and NU ( 94 % ) . Among users of both substances , 93 % reported AU prior to CU ( 87 % for NU ) . After adjustment for ED and parental substance use disorders younger age at AU-onset was associated with any CU . Younger age at NU-onset was associated with earlier CU initiation . Younger age at AU- and NU-onset was not associated with a higher risk of CUD . CONCLUSIONS The cross-substance relevance of younger age at first AU and NU for the risk of CUD is limited to early CU involvement OBJECTIVE We sought to examine the relation between cannabis abuse and the symptomatic course of recent-onset schizophrenia and related disorders . DESIGN A prospect i ve cohort study over a year using monthly Brief Psychiatric Rating Scale assessment s. PARTICIPANTS  Cannabis-abusing patients ( n = 24 ) were compared with nonabusers ( n = 69 ) . Eleven patients were mild and 13 were heavy cannabis-abusing patients . RESULTS Significantly more and earlier psychotic relapses occurred in the cannabis-abusing group ( P = .03 ) . This association became stronger when mild and heavy cannabis abuse were distinguished ( P = .002 ) . No confounding effect of other variables , eg , other street drugs , was found . In all but one patient , cannabis abuse preceded the onset of the first psychotic symptoms for at least 1 year . CONCLUSIONS Cannabis abuse and particularly heavy abuse can be considered a stressor eliciting relapse in patients with schizophrenia and related disorders and possibly a premorbid precipitant Ventricular enlargement and reduced prefrontal volume are consistent findings in schizophrenia . Both are present in first episode subjects and may be detectable before the onset of clinical disorder . Substance misuse is more common in people with schizophrenia and is associated with similar brain abnormalities . We employ a prospect i ve cohort study with nested case control comparison design to investigate the association between substance misuse , brain abnormality , and subsequent schizophrenia . Substance misuse history , imaging data , and clinical information were collected on 147 subjects at high risk of schizophrenia and 36 controls . Regions exhibiting a significant relationship between level of use of alcohol , cannabis or tobacco , and structure volume were identified . Multivariate regression then eluci date d the relationship between level of substance use and structure volumes while accounting for correlations between these variables and correcting for potential confounders . Finally , we established whether substance misuse was associated with later risk of schizophrenia . Increased ventricular volume was associated with alcohol and cannabis use in a dose-dependent manner . Alcohol consumption was associated with reduced frontal lobe volume . Multiple regression analyses found both alcohol and cannabis were significant predictors of these abnormalities when simultaneously entered into the statistical model . Alcohol and cannabis misuse were associated with an increased subsequent risk of schizophrenia . We provide prospect i ve evidence that use of cannabis or alcohol by people at high genetic risk of schizophrenia is associated with brain abnormalities and later risk of psychosis . A family history of schizophrenia may render the brain particularly sensitive to the risk-modifying effects of these substances Rationale Many neuropsychological studies have documented deficits in working memory among recent heavy cannabis users . However , little is known about the effects of cannabis on brain activity . Objective We assessed brain function among recent heavy cannabis users while they performed a working memory task . Methods Functional magnetic resonance imaging was used to examine brain activity in 12 long-term heavy cannabis users , 6–36 h after last use , and in 10 control subjects while they performed a spatial working memory task .  Regional brain activation was analyzed and compared using statistical parametric mapping techniques . Results Compared with controls , cannabis users exhibited increased activation of brain regions typically used for spatial working memory tasks ( such as prefrontal cortex and anterior cingulate ) . Users also recruited additional regions not typically used for spatial working memory ( such as regions in the basal ganglia ) . These findings remained essentially unchanged when re-analyzed using subjects ’ ages as a covariate . Brain activation showed little or no significant correlation with subjects ’ years of education , verbal IQ , lifetime episodes of cannabis use , or urinary cannabinoid levels at the time of scanning . Conclusions Recent cannabis users displayed greater and more widespread brain activation than normal subjects when attempting to perform a spatial working memory task . This observation suggests that recent cannabis users may experience subtle neurophysiological deficits , and that they compensate for these deficits by “ working harder”—calling upon additional brain regions to meet the dem and s of the task Cannabis is among the most frequently abused substances in the United States . Cognitive control is a contributory factor in the maintenance of substance-use disorders and may relate to treatment response . Therefore , we assessed whether cognitive-control-related neural activity before treatment differs between treatment-seeking cannabis-dependent and healthy individuals and relates to cannabis-abstinence measures during treatment and 1-year follow-up . Cannabis-dependent males ( N=20 ) completed a functional magnetic resonance imaging ( fMRI ) cognitive-control ( Stroop ) task before a 12-week r and omized controlled trial of cognitive – behavioral therapy and /or contingency management .  A healthy-comparison group ( N=20 ) also completed the fMRI task . Cannabis use was assessed by urine toxicology and self-report during treatment , and by self-report across a 1-year follow-up period ( N=18 ) . The cannabis-dependent group displayed diminished Stroop-related neural activity relative to the healthy-comparison group in multiple regions , including those strongly implicated in cognitive-control and addiction-related processes ( eg , dorsolateral prefrontal cortex and ventral striatum ) . The groups did not differ significantly in response times ( cannabis-dependent , N=12 ; healthy-comparison , N=14 ) . Within the cannabis-dependent group , greater Stroop-related activity in regions including the dorsal anterior cingulate cortex was associated with less cannabis use during treatment . Greater activity in regions including the ventral striatum was associated with less cannabis use during 1-year posttreatment follow-up . These data suggest that lower cognitive-control-related neural activity in classic ‘ control ’ regions ( eg , dorsolateral prefrontal cortex and dorsal anterior cingulate ) and classic ‘ salience/reward/learning ’ regions ( eg , ventral striatum ) differentiates cannabis-dependent individuals from healthy individuals and relates to less abstinence within-treatment and during long-term follow-up . Clinical ly , results suggest that treatment development efforts that focus on enhancing cognitive control in addition to abstinence may improve treatment outcomes in cannabis dependence In light of exp and ing legalization of cannabis and swelling debate about the potential risks , particularly for younger users , underst and ing acute cannabis effects among adolescents and emerging adults is more important than ever . Contemporary models of addiction development identify subjective drug responses as central to the developmental unfolding of drug use disorders . Despite this , surprisingly little is known about cannabis ’s acute subjective effects in human youths . This research utilized ecological momentary assessment ( EMA ) in the natural environment to identify the typical situational context of cannabis use among 85 frequent cannabis users , ages 15–24 years ( M = 19.8 , SD = 2.0 ; 48.2 % female ) . Study aims were to ( a ) characterize momentary changes in several subjective states ( i.e. , stimulation , sedation , tension , craving , and high ) when not using , just before cannabis use , and after use , and ( b ) evaluate whether cannabis responses varied with cannabis use disorder ( CUD ) severity or across the transition from adolescence to emerging adulthood in a correlational manner . Use of cannabis produced measurable reductions in craving and tension , as well as increases in stimulation , sedation , and “ high . ” Participants with more CUD symptoms reported greater relief of craving and increased stimulatory response and high following use . In contrast , emerging adults reported diminished stimulatory response and high following use , relative to adolescents . Results highlight the utility of EMA for characterizing cannabis response as this behavior unfolds in daily life , during a key developmental timeframe in the pathogenesis of cannabis-use pathology 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 Recent reports show that fewer adolescents believe that regular cannabis use is harmful to health . Concomitantly , adolescents are initiating cannabis use at younger ages , and more adolescents are using cannabis on a daily basis . The purpose of the present study was to test the association between persistent cannabis use and neuropsychological decline and determine whether decline is concentrated among adolescent-onset cannabis users . Participants were members of the Dunedin Study , a prospect i ve study of a birth cohort of 1,037 individuals followed from birth ( 1972/1973 ) to age 38 y.  Cannabis use was ascertained in interviews at ages 18 , 21 , 26 , 32 , and 38 y.  Neuropsychological testing  was conducted at age 13 y , before initiation of cannabis use , and again at age 38 y , after a pattern of persistent cannabis use had developed . Persistent cannabis use was associated with neuropsychological decline broadly across domains of functioning , even after controlling for years of education . Informants also reported noticing more cognitive problems for persistent cannabis users . Impairment was concentrated among adolescent-onset cannabis users , with more persistent use associated with greater decline . Further , cessation of cannabis use did not fully restore neuropsychological functioning among adolescent-onset cannabis users . Findings are suggestive of a neurotoxic effect of cannabis on the adolescent brain and highlight the importance of prevention and policy efforts targeting adolescents We used PET (15)O and a modified version of the Stroop task to determine if 25-day abstinent heavy marijuana ( MJ ) users have persistent deficits in executive cognitive functioning ( ECF ) and brain activity . Performance on a modified version of the Stroop task and brain activity was compared between 25-day abstinent , heavy marijuana users ( n = 11 ) , and a matched comparison group ( n = 11 ) . The 25-day abstinent marijuana users showed no deficits in performance on the modified version of the Stroop task when compared to the comparison group . Despite the lack of performance differences , the marijuana users showed hypoactivity in the left perigenual anterior cingulate cortex ( ACC ) and the left lateral prefrontal cortex ( LPFC ) and hyperactivity in the hippocampus bilaterally , when compared to the comparison group . These results suggest that marijuana users display persistent metabolic alterations in brain regions responsible for ECF . It may be that marijuana users recruit an alternative neural network as a compensatory mechanism during performance on a modified version of the Stroop task . These differences in brain activity may be a common denominator in the evolution of maladaptive behaviors such as substance abuse and other neuropsychiatric disorders Abstract Aims We tested the age‐varying associations of  cannabis use ( CU ) frequency and disorder ( CUD ) with  psychotic , depressive and anxiety symptoms in adolescent and adult sample s. Moderating effects of early onset ( ≤ 15 years ) and sex were tested . Design Time‐varying effect models were used to assess the significance of concurrent associations between CU and CUD  and symptoms of psychosis , depression and anxiety at each age . Setting and Participants Adolescent data ( V‐HYS ; n = 662 ) were collected from a r and omly recruited sample of adolescents in Victoria , British Columbia , Canada during a 10‐year period ( 2003–13 ) . Adult cross‐sectional data ( NESARC‐III ; n = 36 309 ) were collected from a representative sample from the United States ( 2012–13 ) .  Measurements Mental health symptoms were assessed using self‐report measures of diagnostic symptoms . CU was based on frequency of past‐year use . Past‐year CUD was based on DSM‐5 criteria . Findings For youth in the V‐HYS , CU was associated with psychotic symptoms following age 22 [ b = 0.13 , 95 % confidence interval ( CI ) = 0.002 , 0.25 ] , with depressive symptoms from ages 16–19 and following age 25 ( b = 0.17 , 95 % CI = 0.003 , 0.34 ) , but not with anxiety symptoms . CUD was associated with psychotic symptoms following age 23 ( b = 0.51 , 95 % CI = 0.01 , 1.01 ) , depressive symptoms at ages 19–20 and following age 25 ( b = 0.71 , 95 % CI = 0.001 , 1.42 ) and anxiety symptoms ages 26–27 only . For adults in the NESARC‐III , CU was associated with mental health symptoms at most ages [ e.g. psychotic symptoms ; age 18 ( b = 0.22 , 95 % CI = 0.10 , 0.33 ) to age 65 ( b = 0.36 , 95 % CI = 0.16 , 0.56 ) ] . CUD was associated with all mental health symptoms across most ages [ e.g. depressive symptoms ; age 18 ( b = 0.96 , 95 % CI = 0.19 , 1.73 ) to age 61 ( b = 1.11 , 95 % CI = 0.01 , 2.21 ) ] . Interactions with sex show stronger associations for females than males in young adulthood [ e.g. V‐HYS  : CUD × sex interaction on psychotic symptoms significant after age 26 ( b = 1.12 , 95 % CI = 0.02 , 2.21 ) ] . Findings were not moderated by early‐onset CU . Conclusions Significant associations between cannabis use ( CU ) frequency and disorder ( CUD ) and psychotic and depressive symptoms in late adolescence and young adulthood extend across adulthood , and include anxiety A milestone in cannabis research is the establishment of a clinical ly relevant cannabis withdrawal syndrome , yet little is known about the underlying mechanisms . We investigated the predictive role of mental health and cognitive factors in withdrawal severity during an active attempt to cut down , relative to uninterrupted cannabis use . Ninety heavy cannabis users were r and omly assigned to an experimental or control group . The experimental group was asked to cut down substance use for 1 week . Past week substance use , substance use-related problems , depressive symptoms , cravings , and cognitive control were assessed at baseline . Past week substance use and withdrawal severity were assessed at follow-up . The experimental group reduced their cannabis use more and experienced more withdrawal than the control group . Hierarchical regression analysis per predictor indicated that cannabis use-related problems , depressive symptoms , and cannabis craving , but not cognitive control , predicted stronger withdrawal . Craving uniquely predicted withdrawal in the experimental group . A combined hierarchical regression indicated that only depressive symptoms and cannabis use-related problems uniquely predicted withdrawal across groups . These results suggest that depressive symptoms and cannabis use-related problems are generally indicative of cannabis withdrawal severity , whereas craving specifically predicts cannabis withdrawal during an active attempt to cut-down cannabis use BACKGROUND Cannabis use disorder ( CUD ) is a prevalent and impairing condition , and established psychosocial treatments convey limited efficacy . In light of recent findings supporting the efficacy of N-acetylcysteine ( NAC ) for CUD in adolescents , the objective of this trial was to evaluate its efficacy in adults . METHODS In a 12-week double-blind r and omized placebo-controlled trial , treatment-seeking adults ages 18 - 50 with CUD ( N=302 ) , enrolled across six National Drug Abuse Treatment Clinical Trials Network-affiliated clinical sites , were r and omized in a 1:1 ratio to a 12-week course of NAC 1200 mg ( n=153 ) or placebo ( n=149 ) twice daily . All participants received contingency management ( CM ) and medical management . The primary efficacy measure was the odds of negative urine cannabinoid tests during treatment , compared between NAC and placebo participants . RESULTS There was not statistically significant evidence that the NAC and placebo groups differed in cannabis abstinence ( odds ratio=1.00 , 95 % confidence interval 0.63 - 1.59 , p=0.984 ) . Overall , 22.3 % of urine cannabinoid tests in the NAC group were negative , compared with 22.4 % in the placebo group . Many participants were medication non-adherent ; exploratory analysis within medication-adherent subgroups revealed no significant differential abstinence outcomes by treatment group . CONCLUSIONS In contrast with prior findings in adolescents , there is no evidence that NAC 1200 mg twice daily plus CM is differentially efficacious for CUD in adults when compared to placebo plus CM . This discrepant finding between adolescents and adults with CUD may have been influenced by differences in development , cannabis use profiles , responses to embedded behavioral treatment , medication adherence , and other factors The relationships between executive processes , associative learning and different aspects of real world memory functioning were explored in a sample of cannabis users and nonusers . Measures of executive component processes , associative learning , everyday memory , prospect i ve memory , and cognitive failures were administered . Relative to nonusers , cannabis users were found to be impaired in several aspects of real world memory functioning . No other group differences were apparent . The absence of cannabis related deficits in those executive component processes and aspects of learning that are believed to support real world memory processes is surprising given that cannabis related deficits were obtained in real world memory . The present results are discussed within the context of neuroimaging evidence which suggests that cannabis users may exhibit different patterns of neural activation when performing executive tasks while not always exhibiting deficits on these tasks Cannabis use in youth is rising and has been linked to deficits in cognitive functioning . However , cognitive findings have primarily been based on small sample s of users seeking treatment , and few studies have evaluated cognition in occasional cannabis users . Here , we examined 4,568 adolescents and young adults ( ages 14–21 years ) drawn from the Philadelphia Neurodevelopmental Cohort , a prospect i ve , population -based study . Participants were classified as cannabis Non-Users ( n = 3,401 ) , Occasional Users ( twice per week or less ; n = 940 ) , or Frequent Users ( > 3 times per week ; n = 227 ) . Mixed-model analyses examined main effects of cannabis use and interactions between age and cannabis use on cognitive functioning . There was a significant interaction between cannabis group and age such that adolescent ( but not young adult ) Frequent Users performed worse than Non-Users on measures of executive control ( p = .002 ) . Earlier age of cannabis use was associated with worse performance in executive control in Occasional Users ( p = .04 ) . Unexpectedly , Occasional Users exhibited better executive control , memory , and social cognition than Non-Users ( ps < .05 ) . Although mild executive control deficits in adolescent frequent users and a relation between early cannabis initiation and cognitive performance are partially consistent with prior research , cognitive deficits were not found in other hypothesized domains in this community-based sample . Moreover , occasional cannabis users displayed equivalent or even slightly better executive control , social – cognitive , and memory abilities compared with nonusers , suggesting complex relationships between cannabis use and cognition in youth . Longitudinal studies with community sample s are needed to identify variables affecting risk and resilience to cognitive deficits associated with cannabis
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 .