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Maybe that's why they don't have that issue! Humans naturally produce their own cannabinoids but some don't produce enough.
When they were considering legalizing recreational cannabis in California a while back one of the fellows who had worked to get medical cannabis legal wrote a piece about how all cannabis use is in fact medicinal and therefore he was going to vote against legalization, nothing to do of course with the fact that he was personally profiting from and dependent on the medical paradigm. He made a pretty good argument though, people who smoke pot "recreationally" or in social settings are doing so to ease social anxiety and social anxiety is a recognized psychiatric condition.

I forgot a "don't":

Many ppl don't have this issue and they don't ingest cannabis ;)

Smoking or taking substances that get you high is also escapism as a stress reliever ;)

he might say that nonspecific "stress" is a "general anxiety" and if it is so bad that you need to take a substance to relieve it then technically that does qualify as a Generalized Anxiety Disorder and then it's medical use.