The officer was an idiot. Don't believe anything he said and consider filing a complaint.

It is urgent that you get in touch with his pdoc and a plan in place before he turns 18. Once May 1st gets here, everyone's hands are tied. I hope pdoc is responsive. Let him know about the adderall. Perhaps he will want to hold off treating the ADHD or switch to something with less abuse potential. I also think some drugs can be monitored in the blood stream. Pdoc might decide that he will no longer be rx'ing adderall unless blood tests show he is taking a mood stabilizer.

Would pdoc do a joint meeting with you and your son?

This is not a parenting issue. Don't blame yourself.

Good luck,
EJ