This is an extremely difficult situation. He is 23, so he is no longer a minor. He refuses to address or admit he has a problem, and he is engaging in a very unhealthy behavior that could have severe consequences, not only for him, but for you as well. This will not be an easy situation to deal with because it is nearly impossible to help people who don't want help.
The first thing I would like to do is refer you to an organization called Al-Anon. Al-Anon is a group that works with families who have alcoholics or other addicts in their family. It is not for the people who are addicted, it is for the people who are close to the addicts. Here is there website, please check them out and consider giving them a call.
The second thing that we recommend is that if he lives in your house you make the consequences of finding marijuana in the house or him coming home high very clear, and then follow through with the consequences you set. It may be in your best interest to call the police if you find marijuana in the home because if you get caught with it there, you're the one who will be in trouble. It is your home and you are responsible for anything that is there. You can set what the consequences are for these situations, but make sure that you follow through with them. You can also give him regular drug tests. They have these available at most drug stores and you can make consequences for if he tests positive. You could also say that if he doesn't quit he will not be welcome to stay unless he agrees to get treatment. It may be wise to call a treatment facility in your area and talk with them as well and see if they have ideas about what these consequences may be as they will have extensive knowedge in these areas.
Other than that, continue to let your son know you are worried about him. Tell him your concerns and why they are your concerns. Let him know you will not stand by and watch your own son take these risks and chances with his well being. Also refer him to the website below, which may be able to assist him on this journey.
So, given that your son is 23 he is an adult and as such is responsible for his own behavior. If he still lives at home you might have some leverage, but if he doesn't live at home then I don't think there is much you can do other than make sure he knows your views on marijuana use. Many young adults experiment with marijuana but what you describe sounds more serious. If your son is using marijuana to avoid dealing with other issues (economic, relationship?), maybe you can help with them.
Jeanne H. Brockmyer, Ph. D. education.com expert clinical psychologist
It makes me sad how uninformed the public is on marijuana. This so called drug isn't even remotely bad for you. I'm not going to get in an argument about how marijuana is physically addicting or how it kills its users, because the truth is it doesn't! I know I'm going to get negative responses to this answer because this site is filled with so called "experts" who in reality are extremely uneducated on this subject. The only logical reasoning to anti marijuana critics is that some marijuana users eventually move on to using much harder and dangerous drugs such as heroin, cocaine, and meth. I do not deny this fact, but it is NO more of a gateway drug than alcohol and tobacco, which are both legal. Bottom line is marijuana has never killed anybody and never will. Your son is completely fine. Here are a few links describing why marijuana is illegal and one showing how aspirin is more dangerous than marijuana.
ok. the fact that you have "conversations" and stated he uses on a regular basis, leads me to believe he still lives at home and/or in close proximity to you. One writer, readabook, I think is right about marijuana not being any more of a gateway to harder drugs than legal stuff like booze, painkillers,etc. The main problem I see here is two fold, you don't like it - and it's going on in your living "area" so to speak, but I'd like to know what else is your son into? Is he a grad student somewhere, have a decent job that he goes to on time or is he a "bum" because if he's a irresponsible bum and disrespectful of your wishes on top of that, I'd put him out-with the quick-ness! However, if he's other wise responsible pays his way and saving to move out or in grad school or what ever, I'd let him know it bothers me, keep it confined to his own personal area and keep saving to hurry up and move out. Now, I speak this way because I too have a 23 y.o. and she's a college grad and working and saving to get independent but she has "ways" I don't approve of. She knows how I feel and I don't beat her over the head with it either because at the end of the day I want to always have a "pleasant" relationship with her rather than her feeling she can't talk to me and I believe that as she matures; I will eventually love her back to a place where she will no longer give space to those types of "behaviors" or "habits".