I loved your post and will read it to one of the adolescents I work with who has a bit of a problem with substance abuse. Great attitude.
I've been through it all. Ex-drug user, ex-alcoholic, former psychotherapy guinea pig, took doctor prescribed anti-depressents etc. Was also an atheist. Attempted suicide once, seriously, and engaged in near suicidal behavior for years. Suffered from severe depression, uncontrollable anger, you name it.
Now? I'm a different person altogether. How? God cured me. If it can happen to me, it can happen to anyone - if they want Him badly enough, and are willing to go through the work. A person has to want to see themselves as they are - covered with warts - and be willing to accept that God loves me anyway. And then try without ever giving up, to become the person we really are, in gratitude. God will help every step of the way, it doesn't matter how deep in misery and sin we are to begin with.