Paulita   Thank you for your question and welcome to ADHDCentral.com.   Unfortunately, once your son turns 18, he is legally responsible for any treatment as well as is responsible for his actions (or his inactions). I know this is difficult, but you must decide what you are going to allow in your house and what you will not accept. I know (first hand) what a difficult decision is and how much this situation hurts you everyday. Please know that you are not alone.   I am providing you with some links to some additional information:   When Children with ADD Become Adults   Substance Abuse in Teens With ADHD   Tough Love   When Teens With ADHD Are Defiant   Adult Children with ADD Living at Home   I hope this helps.   Eileen