I want to find out if my 26 year son could have some kind of mental illness or if its due to drinking but I am not sure where to start. I think he has a drinking problem. He has periods where he is very interactive with our family, very involved, happy, positive, focused, honest, upfront, shares, he has goals and dreams and he seems happy. But there are times when he is very withdrawn, quite, angry, lies, secretively, negative, no goals or dreams and seems very depressed.