I think it varies from person to person.
My doc recommended mj for anxiety/mood/pain (this was after he almost killed me from withdrawing benzos too rapidly and would not help with my chronic headaches after I had a craniotomy).
In any case, it did not help at all for me, but I hear it does help some people.
Just be careful. The designer strains today (as opposed to the natural strains of a long time ago) tend to be be much, much stronger.
I had trouble with a 50:50 ratio of CBD:mj (just about coughed my lungs out), so I tried a 1:9 ratio of CBD:MJ after I was told it was more smooth on the lungs - big mistake!
Two hits and I was hallucinating - it was pretty nasty. I knew what was happening though and was able to wait it out - it did resolve.
Also if you go the edible or tincture route, the time to onset of effect is longer when compared with inhaled mj, which takes effect almost immediately.
Many have made the mistake of taking an edible or tincture and because the time to onset of effect is longer, they figure it isn't working, so they take more. Also a big mistake.
Personally, I won't touch the stuff now. But again, that is me and my weird metabolism.
Many anecdotal reports from people say that it does help.
Oh and Indica is said to be more calming and Sativa more energizing. For me, it was Indica they recommended.
<3
On edit: Also, be careful, I have heard rare reports of mj causing psychosis in younger people who use it - course that could be hype or it could have been caused by something else. If you do decide to try it, just go slow at first. : )