Any kind of addiction is bad for a person's mental state. Recovering from a high can cause a lot of emotional and mood problems. To stay healthy, it's important to stay away from all drugs, including marijuana. Addiction is a serious condition, and recoveryis a long and drawn out process.
Marijuana has already been proven to not cause any kind of side effect to the person that uses them. I mean, yes they do act more relaxed and care free when they use them but that is nothing as extreme and worrying as a disorder or depression. I mean marijuana is even being use medicinally which has proven to help people in the situation where they need it.