YEs marijuana can hurt you it can never be good for you . If somebody is hurt or upset, they can over dose it and go ina point of no return. There have been people who have lost themselves and committed suicide because of Pot. They have lost families and they can never hurt themselves enough so its very dangerous
You cannot overdose on Marijuana. However, marijuana can impair your motor skills in a way alcohol does, therefore there should be much heavier punishment to those who use it and operate a motor vehicle or perform a daily job while being high on marijuana. Marijuana use seems to be more common than ever before, and that is certainly negative.
Marijuana is a plant that is famous for containing the substance THC. Chemically, THC is only able to saturate the users' blood to such a level, that ingesting any more THC would become "useless". Thus, pot is literally unable to kill someone by taking too much of it. This is also the reason why there is not a single instance of medical overdose of marijuana.
A grown adult can not overdose on marijuana. The reason behind this is because you need to ingest 40,000 times the amount needed to intoxicate you. That is just not possible. On the other hand small children have almost died because of accidental ingestion, but their bodies are much smaller. Essentially no research has been done to prove the unbiased side of this, but I don't believe anyone is going to try and ingest a lethal dose of THC.