system
Given the following post, respond as if you're commenting on Reddit:
human
How does cannabis cause schizophrenia?

I've been doing some reading on this topic and the literature generally seems to show a link between cannabis and schizophrenia, whereby those who are genetically vulnerable to schizophrenia are much more likely to develop schizophrenia after taking cannabis, and those who are not at-risk are also likely to develop schizophrenia after taking cannabis. But my question is what explains this link? 

A lot of the studies I've read have also shown that cannabis does create a psychosis experience for the individual, such as hallucinations etc., but this tends to wear off within a few days of abstinence. If it this psychosis experience wears off, how can cannabis cause schizophrenia then? I'm genuinely interested in this area and want to understand it better. 

Also, a ton of papers and websites I've read have all said something along the lines of "cannabis use may precipitate schizophrenia or exacerbate its symptoms" - truthfully, i don't quite know what that even means and how that links to at-risk and not at-risk groups. If anyone could provide a clarification to this, it would be much appreciated.

Thanks in advance!
gpt
>those who are genetically vulnerable to schizophrenia are much more likely to develop schizophrenia after taking cannabis, and those who are not at-risk are also likely to develop schizophrenia after taking cannabis. 

The problem with this is that you can never really infer causality here. You will never know if a given person would have developed schizophrenia if they had *not* used marijuana. Because we can't know, we can only state that there is a correlation between cannabis use and schizophrenia. The link is likely bi-directional. It is often the case that people with mental illnesses use substances as a form of self medication (they feel that it eases some subjective symptom, like anxiety for instance). So those individuals may be more likely to use substances to begin with. 

As for any brain mechanisms that link cannabis with psychosis, I'll let someone familiar with the neuroscience weigh in.