How can I explain to a teeneager that Medical marijuana is OK for patients w/prescriptions but not for them??

Cancer patients and other patients find relief using medical Marijuana. It may be OK for them but I still dont want my young at heart teenagers using it...they think its a double standard and dont win it...any ideas on how to construct them understand?? supposedly the pot is supposed to straightforwardness the nausea and the pain associated next to the cancer treatment. I smoked pot a lot for almost 25 years. I presently have a especially hard time remembering things. I will seize into my car and drive to the store forgetting why I go in the first place. My sense of smell is gone and I own a poor taste as economically. So if your teenager requirements to grow up a dummy that can't taste, smell or remember it is ok. Not to mention it lead to other drugs for me I am a recovering addict and alcoholic because of my choice to smoke a touch pot. And oh yes it is against the law and will cost a pouring fine not to mention jail time. Good luck.
Because patients are surrounded by severe pain and they are smoking because they own to not because they want to