THC is naturally occuring the body at a small amount - it is the reason we have the CB1 and CB2 receptor sites, and that is what THC binds to. THC and cannaboids that are active are not harmful to the body, but the smoke can cause lung problems and the *smoke* can cause cancer. Ediable cannabis bypasses both these things.
Your short term memory... well, I've written up a 2 page response to another poster about that in the past. Short version is binding sites are located in and around the hippocampus, which is where your short term memory is. Smoking can... um... im going to dumb this down for you... Getting high essentially makes your short term memory shot because it is busy being high and not processing cystaline data or fluid memory. It's not permanent damage. If you stop smoking for a few months your memory should return to as good as new. You haven't "lost" your smarts and common knowledge, you've clouded it in a haze of high. If you're on drugs, that's not a hard connection to draw even without being a neurologist or psychiatrist.
Use the search engine as this is extensively covered in tons of other threads.
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