Did you read the conclusions?
“ CONCLUSION
We have examined the neurobiological changes due to cannabis to see if these changes are similar to those seen in schizophrenic patients the findings show strange similarities; however, none of these studies have been able to establish a possible long-term longitudinal course for these changes. These mere similarities cannot establish a ‘cause-effect’ relationship, since a number of people with similar changes do not develop schizophrenia. Therefore, the ‘transition-to-psychosis’ due to cannabis, despite it being a strong risk factor, remains uncertain based upon neurobiological changes. It appears that multiple other factors might be involved in these processes which are beyond neurobiological factors. Major advances have been made in understanding the underpinning of marijuana dependence and the role of the CNS cannabinoid system, which is a major area for targeting medications to treat marijuana withdrawal and dependence, as well as other addictions is of now, it is clear that some of the similarities in neurobiology of cannabis and schizophrenia may indicate a mechanism for development of psychosis but its trajectories are undetermined.”
So your definitive statement is absolute BS.
I can show you 100 psychos walking around outside my office building who can show you otherwise.
I can’t see that your text discounts anything. Heavy cannabis use is certainly risky behavior by any measure. “...a strong risk factor.” jmo, though it seems obvious to the objective observer.