Interesting question. For me, it reduces anxiety when I have a challenging deadline and I have OCD thoughts that prevent me from making progress. It did increase my anxiety in some ways- I always had to worry that somebody would find out and it would have consequences. That anxiety is now gone because it's legalized.

It actually can do both. It depends on the specifics of the person and the strain. In particular, I think Indica strains are supposed to be less likely to create or exacerbate anxiety.

Honestly, the science is still incomplete. We do know that there is quite a bit of genetic variation that comes into play with regards to how THC affects the user though.