If he was 1 when you adopted him, then he may well have suffered severe developmental issues in early childhood. Babies need the right kind of contact with a carer (ideally the parent), or they develop attachment disorder. Their brains often don't 'wire up' correclty, leading to often severe MH issues.
I speak from expereince, having a very troubled granddaughter in my family who was removed from her birth mother at a year old after severe neglect. Adopted children often suffer with MH problems because the mechanisms of attachment are not still well-understood. Your DS is doing more or less exaclty what my DGD did.
Support is scandalously lacking. At his age, he may well reject counselling or therapy, but good therapy can help. Throwing him out isn't the answer. What happened to him in early childhood is not his fault. It isn't yours either, though it sounds as though you were not properly informed about the issues involved in taking this damaged child on. With my DGD, who is now 21, it was all in the small print in the sheaves of adoption papers, but nothing was highlighted.
My nephew and his wife adopted seven years ago, and they were a lot more clued up about what to expect and how to try and work around the damage. Their DG seems to be doing well, so far. Therapeutic parenting is the system recommended to them. This may be too late for your DS, but try and get help from the experts.
This is very tough. I have a lot of sympathy. My DGD ran away at 16, first to an abusinve man, then to her birth family. She has done the whole drugs, sex, drink thing. A lot of the time she lived away from home by her own choice which gave us a break.
We maintained contact, made sure she knew we were there for her and we loved her. She is stabilising a bit now, and things are improving, but the damage is for life. She will always make unwise, impulsive choices, will probably always be prone to sabotage her own life when it is getting better - the damage done in those crucual twelve months can't easily be repaired, especially if you weren't given the advice, help and support you needed when your DS was a baby.
Don't throw him out. Get advice, make a fuss if it isn't offered quickly, make sure he knows you love him, keep the communication channels open.