The results show that , in particular , frequent cannabis use , especially daily use , and the consumption of high-potency cannabis are associated with a higher risk of developing psychosis .
Moreover , several genotypes moderate the impact of cannabis use on psychosis risk , particularly those involved in the dopamine function , such as AKT1 .
Finally , cannabis use is associated with an earlier psychosis onset and increased risk of transition in individuals at a clinical high risk of psychosis .
These findings indicate that changing cannabis use behavior could be a harm reduction strategy employed to lower the risk of developing psychosis .
Increasing evidence indicates a relationship between  cannabis use and psychosis risk .
Specific factors , such as determinants of cannabis use or the genetic profile of cannabis users , appear to moderate this association .
The present systematic review presents a detailed and up-to- date literature overview on factors that influence the relationship between cannabis use and psychosis risk .
Cannabis use disorders in schizophrenia: Effects on cognition and symptoms
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
The results show that , in particular , frequent cannabis use , especially daily use , and the consumption of high-potency cannabis are associated with a higher risk of developing psychosis .
Moreover , several genotypes moderate the impact of cannabis use on psychosis risk , particularly those involved in the dopamine function , such as AKT1 .
Finally , cannabis use is associated with an earlier psychosis onset and increased risk of transition in individuals at a clinical high risk of psychosis .
These findings indicate that changing cannabis use behavior could be a harm reduction strategy employed to lower the risk of developing psychosis .
Increasing evidence indicates a relationship between  cannabis use and psychosis risk .
Specific factors , such as determinants of cannabis use or the genetic profile of cannabis users , appear to moderate this association .
The present systematic review presents a detailed and up-to- date literature overview on factors that influence the relationship between cannabis use and psychosis risk .