I hope you're right about ending the drug war.
Are you sure about this: "There is nothing wrong mentally or physically with them."
Prior to the industrial era, I've been unable to find historical information about "rebellious teens". Whether they existed or not is not the main point. The modern teenage years are times of gargantuan stress. Not only puberty, dating, and those kinds of physical things, but all the work (labor) required without monetary payment, the 'high stakes' testing, yada yada, the pressure to get college degree so they can qualify to work as a burger flipper (in this job market). My point is it's possible that the MM your 18 year old kids' friends are using is a "self medication" to help them cope with the extreme mental stress our civilization forces upon them today.
Additionally, you do not know that there is nothing physically wrong with them. It merely "seems" that way to you, based upon appearances. Remember, medical records are supposed to be private. When folks reveal they have an illness, predators come out of nowhere to take advantage. Putting on the appearance of health, when the opposite is the actual case, seems to be quite normal and natural.