There can be a mental addiction for some people. Meaning, they feel they need it.
There is not a physical addiction to cannabis like there is tobacco, alcohol, caffeine, and most drugs whether prescribed or OTC.
As an athlete, you can either smoke a bowl after working out (which most body builders do as well) or you can go drink. Drinking causes you to be hung over the next day, and takes about 3 days to get back to 100% after a hard night of drinking. As for cannabis, you can smoke your brains out, pass out, and be fine the next day. You might hack some %^&* up if you smoked blunts, but thats not the cannabis, thats the stuff from the blunt wrap.
NO ONE IN THE HISTORY OF THE WORLD HAS EVER OVERDOSED ON CANNABIS!