Strangely enough, marijuana can also cause anxiety during a come down from a high because of the anxiolytic effects of the high. The high relaxes you but as you come down you can experience anxiety that "rebounds" even stronger than it was before. But like the cognitive effects, this should return to normal if you don't blaze after a while.
At my university (UCR), there is one professor who is allowed to work with marijuana. He is the only one and it's very strictly monitored. As more professors are allowed to study it, we should find out more info on it as time comes.
This study shows just how complicated it all is:
"cannabinoids have other targets than CB receptors"
Not even the signalling mechanisms of cannabinoids are understood. If we don't know what it's signalling and setting off in the brain how can we even know what the effects are?
Anyways, I guess what I'm trying to say is that the academic portion of this thread is exhausted. We just don't know what it does! So, just keep to the vaporizers and edibles to save your lungs (can't workout if you can't breathe) and keep on toking! If you smoke everyday, try taking a day or two off every month to keep your tolerance down, save money, and give your brain a break.
edit: if anyone else has some academic info please post it up--otherwise, on to personal experiences!