I'm a mom of a highly volatile, very intelligent and charming and sick young man. I am divorced and he is my only adopted son and I am heart broken, scared, and at a loss of what to do ,both for him, and myself.
It is too bad you didnt get the medicals on the birth parents.
Drugs and alcohol taken while a developing fetus is in utero WILL cause various damage to the brain and very often behavioral problems. If his DNA also i cludes mental illness or addiction, these are hereditary.
We adopted three kids and had the history of the birth family and medicals. One son was born with coke in his system and he has no behavior problems but he does have autism, probably caused by prenatal drug ingestion.
Your son was born with a harder deck of cards if he was exposed to substances in the womb. Son is not at fault for that either. Please dont take the blame for this and try to be good to yourself. Therapy may really help you.
Light and love!